// TODO UITextbox features - mouse input, multi-line, clipboard, undo, IME support, number dragging.
// TODO New elements - list view, menu bar.
// TODO Keyboard navigation - menus, dialogs, tables.
// TODO Easier to use fonts; GDI font support.
// TODO Formalize the notion of size-stability? See _UIExpandPaneButtonInvoke.

#include <stdint.h>
#include <stddef.h>
#include <stdbool.h>
#include <stdarg.h>

#ifdef UI_LINUX
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/Xatom.h>
#include <X11/cursorfont.h>

#include <xmmintrin.h>
#endif

#define _UI_TO_STRING_1(x) #x
#define _UI_TO_STRING_2(x) _UI_TO_STRING_1(x)

#ifdef UI_WINDOWS
#undef _UNICODE
#undef UNICODE
#include <windows.h>

#define UI_ASSERT(x) do { if (!(x)) { ui.assertionFailure = true; \
	MessageBox(0, "Assertion failure on line " _UI_TO_STRING_2(__LINE__), 0, 0); \
	ExitProcess(1); } } while (0)
#define UI_CALLOC(x) HeapAlloc(ui.heap, HEAP_ZERO_MEMORY, (x))
#define UI_FREE(x) HeapFree(ui.heap, 0, (x))
#define UI_MALLOC(x) HeapAlloc(ui.heap, 0, (x))
#define UI_REALLOC _UIHeapReAlloc
#define UI_CLOCK GetTickCount
#define UI_CLOCKS_PER_SECOND (1000)
#define UI_CLOCK_T DWORD
#endif

#if defined(UI_LINUX)
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <time.h>
#include <math.h>

#define UI_ASSERT assert
#define UI_CALLOC(x) calloc(1, (x))
#define UI_FREE free
#define UI_MALLOC malloc
#define UI_REALLOC realloc
#define UI_CLOCK clock
#define UI_CLOCKS_PER_SECOND CLOCKS_PER_SEC
#define UI_CLOCK_T clock_t
#endif

#if defined(UI_ESSENCE)
#include <essence.h>

#define UI_ASSERT EsAssert
#define UI_CALLOC(x) EsHeapAllocate((x), true)
#define UI_FREE EsHeapFree
#define UI_MALLOC(x) EsHeapAllocate((x), false)
#define UI_REALLOC(x, y) EsHeapReallocate((x), (y), false)
#define UI_CLOCK EsTimeStampMs
#define UI_CLOCKS_PER_SECOND 1000
#define UI_CLOCK_T uint64_t

// Callback to allow the application to process messages.
void _UIMessageProcess(EsMessage *message);
#endif

#ifdef UI_DEBUG
#include <stdio.h>
#endif

#ifdef UI_FREETYPE
#include <ft2build.h>
#include FT_FREETYPE_H
#include <freetype/ftbitmap.h>
#endif

#define UI_SIZE_BUTTON_MINIMUM_WIDTH (100)
#define UI_SIZE_BUTTON_PADDING (16)
#define UI_SIZE_BUTTON_HEIGHT (27)
#define UI_SIZE_BUTTON_CHECKED_AREA (4)

#define UI_SIZE_CHECKBOX_BOX (14)
#define UI_SIZE_CHECKBOX_GAP (8)

#define UI_SIZE_MENU_ITEM_HEIGHT (24)
#define UI_SIZE_MENU_ITEM_MINIMUM_WIDTH (160)
#define UI_SIZE_MENU_ITEM_MARGIN (9)

#define UI_SIZE_GAUGE_WIDTH (200)
#define UI_SIZE_GAUGE_HEIGHT (22)

#define UI_SIZE_SLIDER_WIDTH (200)
#define UI_SIZE_SLIDER_HEIGHT (25)
#define UI_SIZE_SLIDER_THUMB (15)
#define UI_SIZE_SLIDER_TRACK (5)

#define UI_SIZE_TEXTBOX_MARGIN (3)
#define UI_SIZE_TEXTBOX_WIDTH (200)
#define UI_SIZE_TEXTBOX_HEIGHT (27)

#define UI_SIZE_TAB_PANE_SPACE_TOP (2)
#define UI_SIZE_TAB_PANE_SPACE_LEFT (4)

#define UI_SIZE_SPLITTER (8)

#define UI_SIZE_SCROLL_BAR (16)
#define UI_SIZE_SCROLL_MINIMUM_THUMB (20)

#define UI_SIZE_CODE_MARGIN (ui.activeFont->glyphWidth * 5)
#define UI_SIZE_CODE_MARGIN_GAP (ui.activeFont->glyphWidth * 1)

#define UI_SIZE_TABLE_HEADER (26)
#define UI_SIZE_TABLE_COLUMN_GAP (20)
#define UI_SIZE_TABLE_ROW (20)

#define UI_SIZE_PANE_MEDIUM_BORDER (5)
#define UI_SIZE_PANE_MEDIUM_GAP (5)
#define UI_SIZE_PANE_SMALL_BORDER (3)
#define UI_SIZE_PANE_SMALL_GAP (3)

#define UI_SIZE_MDI_CHILD_BORDER (6)
#define UI_SIZE_MDI_CHILD_TITLE (30)
#define UI_SIZE_MDI_CHILD_CORNER (12)
#define UI_SIZE_MDI_CHILD_MINIMUM_WIDTH (100)
#define UI_SIZE_MDI_CHILD_MINIMUM_HEIGHT (50)
#define UI_SIZE_MDI_CASCADE (30)

#define UI_UPDATE_HOVERED (1)
#define UI_UPDATE_PRESSED (2)
#define UI_UPDATE_FOCUSED (3)

typedef enum UIMessage {
	UI_MSG_PAINT, // dp = pointer to UIPainter
	UI_MSG_LAYOUT,
	UI_MSG_DESTROY,
	UI_MSG_UPDATE, // di = UI_UPDATE_... constant
	UI_MSG_ANIMATE,
	UI_MSG_SCROLLED,
	UI_MSG_GET_WIDTH, // di = height (if known); return width
	UI_MSG_GET_HEIGHT, // di = width (if known); return height
	UI_MSG_FIND_BY_POINT, // dp = pointer to UIFindByPoint; return 1 if handled
	UI_MSG_CLIENT_PARENT, // dp = pointer to UIElement *, set it to the parent for client elements

	UI_MSG_INPUT_EVENTS_START, // not sent to disabled elements
	UI_MSG_LEFT_DOWN,
	UI_MSG_LEFT_UP,
	UI_MSG_MIDDLE_DOWN,
	UI_MSG_MIDDLE_UP,
	UI_MSG_RIGHT_DOWN,
	UI_MSG_RIGHT_UP,
	UI_MSG_KEY_TYPED, // dp = pointer to UIKeyTyped; return 1 if handled
	UI_MSG_MOUSE_MOVE,
	UI_MSG_MOUSE_DRAG,
	UI_MSG_MOUSE_WHEEL, // di = delta; return 1 if handled
	UI_MSG_CLICKED,
	UI_MSG_GET_CURSOR, // return cursor code
	UI_MSG_PRESSED_DESCENDENT, // dp = pointer to child that is/contains pressed element
	UI_MSG_INPUT_EVENTS_END,

	UI_MSG_VALUE_CHANGED, // sent to notify that the element's value has changed
	UI_MSG_TABLE_GET_ITEM, // dp = pointer to UITableGetItem; return string length
	UI_MSG_CODE_GET_MARGIN_COLOR, // di = line index (starts at 1); return color
	UI_MSG_CODE_DECORATE_LINE, // dp = pointer to UICodeDecorateLine
	UI_MSG_WINDOW_CLOSE, // return 1 to prevent default (process exit for UIWindow; close for UIMDIChild)
	UI_MSG_TAB_SELECTED, // sent to the tab that was selected (not the tab pane itself)
	UI_MSG_WINDOW_DROP_FILES, // di = count, dp = char ** of paths
	UI_MSG_WINDOW_ACTIVATE,

	UI_MSG_USER,
} UIMessage;

#ifdef UI_ESSENCE
#define UIRectangle EsRectangle
#else
typedef struct UIRectangle {
	int l, r, t, b;
} UIRectangle;
#endif

typedef struct UITheme {
	uint32_t panel1, panel2, selected, border;
	uint32_t text, textDisabled, textSelected;
	uint32_t buttonNormal, buttonHovered, buttonPressed, buttonDisabled;
	uint32_t textboxNormal, textboxFocused;
	uint32_t codeFocused, codeBackground, codeDefault, codeComment, codeString, codeNumber, codeOperator, codePreprocessor;
} UITheme;

typedef struct UIPainter {
	UIRectangle clip;
	uint32_t *bits;
	int width, height;
#ifdef UI_DEBUG
	int fillCount;
#endif
} UIPainter;

typedef struct UIFont {
	int glyphWidth, glyphHeight;

#ifdef UI_FREETYPE
	bool isFreeType;
	FT_Face font;
	FT_Bitmap glyphs[128];
	bool glyphsRendered[128];
	int glyphOffsetsX[128], glyphOffsetsY[128];
#endif
} UIFont;

typedef struct UIShortcut {
	intptr_t code;
	bool ctrl, shift, alt;
	void (*invoke)(void *cp);
	void *cp;
} UIShortcut;

typedef struct UIStringSelection {
	int carets[2];
	uint32_t colorText, colorBackground;
} UIStringSelection;

typedef struct UIKeyTyped {
	char *text;
	int textBytes;
	intptr_t code;
} UIKeyTyped;

typedef struct UITableGetItem {
	char *buffer;
	size_t bufferBytes;
	int index, column;
	bool isSelected;
} UITableGetItem;

typedef struct UICodeDecorateLine {
	UIRectangle bounds;
	int index; // Starting at 1!
	int x, y; // Position where additional text can be drawn.
	UIPainter *painter;
} UICodeDecorateLine;

typedef struct UIFindByPoint {
	int x, y;
	struct UIElement *result;
} UIFindByPoint;

#define UI_RECT_1(x) ((UIRectangle) { (x), (x), (x), (x) })
#define UI_RECT_1I(x) ((UIRectangle) { (x), -(x), (x), -(x) })
#define UI_RECT_2(x, y) ((UIRectangle) { (x), (x), (y), (y) })
#define UI_RECT_2I(x, y) ((UIRectangle) { (x), -(x), (y), -(y) })
#define UI_RECT_2S(x, y) ((UIRectangle) { 0, (x), 0, (y) })
#define UI_RECT_4(x, y, z, w) ((UIRectangle) { (x), (y), (z), (w) })
#define UI_RECT_WIDTH(_r) ((_r).r - (_r).l)
#define UI_RECT_HEIGHT(_r) ((_r).b - (_r).t)
#define UI_RECT_TOTAL_H(_r) ((_r).r + (_r).l)
#define UI_RECT_TOTAL_V(_r) ((_r).b + (_r).t)
#define UI_RECT_SIZE(_r) UI_RECT_WIDTH(_r), UI_RECT_HEIGHT(_r)
#define UI_RECT_TOP_LEFT(_r) (_r).l, (_r).t
#define UI_RECT_BOTTOM_LEFT(_r) (_r).l, (_r).b
#define UI_RECT_BOTTOM_RIGHT(_r) (_r).r, (_r).b
#define UI_RECT_ALL(_r) (_r).l, (_r).r, (_r).t, (_r).b
#define UI_RECT_VALID(_r) (UI_RECT_WIDTH(_r) > 0 && UI_RECT_HEIGHT(_r) > 0)

#define UI_COLOR_ALPHA_F(x) ((((x) >> 24) & 0xFF) / 255.0f)
#define UI_COLOR_RED_F(x) ((((x) >> 16) & 0xFF) / 255.0f)
#define UI_COLOR_GREEN_F(x) ((((x) >> 8) & 0xFF) / 255.0f)
#define UI_COLOR_BLUE_F(x) ((((x) >> 0) & 0xFF) / 255.0f)
#define UI_COLOR_ALPHA(x) ((((x) >> 24) & 0xFF))
#define UI_COLOR_RED(x) ((((x) >> 16) & 0xFF))
#define UI_COLOR_GREEN(x) ((((x) >> 8) & 0xFF))
#define UI_COLOR_BLUE(x) ((((x) >> 0) & 0xFF))
#define UI_COLOR_FROM_FLOAT(r, g, b) (((uint32_t) ((r) * 255.0f) << 16) | ((uint32_t) ((g) * 255.0f) << 8) | ((uint32_t) ((b) * 255.0f) << 0))
#define UI_COLOR_FROM_RGBA_F(r, g, b, a) (((uint32_t) ((r) * 255.0f) << 16) | ((uint32_t) ((g) * 255.0f) << 8) \
		| ((uint32_t) ((b) * 255.0f) << 0) | ((uint32_t) ((a) * 255.0f) << 24))

#define UI_SWAP(s, a, b) do { s t = (a); (a) = (b); (b) = t; } while (0)

#define UI_CURSOR_ARROW (0)
#define UI_CURSOR_TEXT (1)
#define UI_CURSOR_SPLIT_V (2)
#define UI_CURSOR_SPLIT_H (3)
#define UI_CURSOR_FLIPPED_ARROW (4)
#define UI_CURSOR_CROSS_HAIR (5)
#define UI_CURSOR_HAND (6)
#define UI_CURSOR_RESIZE_UP (7)
#define UI_CURSOR_RESIZE_LEFT (8)
#define UI_CURSOR_RESIZE_UP_RIGHT (9)
#define UI_CURSOR_RESIZE_UP_LEFT (10)
#define UI_CURSOR_RESIZE_DOWN (11)
#define UI_CURSOR_RESIZE_RIGHT (12)
#define UI_CURSOR_RESIZE_DOWN_RIGHT (13)
#define UI_CURSOR_RESIZE_DOWN_LEFT (14)
#define UI_CURSOR_COUNT (15)

#define UI_ALIGN_LEFT (1)
#define UI_ALIGN_RIGHT (2)
#define UI_ALIGN_CENTER (3)

extern const int UI_KEYCODE_A;
extern const int UI_KEYCODE_BACKSPACE;
extern const int UI_KEYCODE_DELETE;
extern const int UI_KEYCODE_DOWN;
extern const int UI_KEYCODE_END;
extern const int UI_KEYCODE_ENTER;
extern const int UI_KEYCODE_ESCAPE;
extern const int UI_KEYCODE_F1;
extern const int UI_KEYCODE_HOME;
extern const int UI_KEYCODE_LEFT;
extern const int UI_KEYCODE_RIGHT;
extern const int UI_KEYCODE_SPACE;
extern const int UI_KEYCODE_TAB;
extern const int UI_KEYCODE_UP;
extern const int UI_KEYCODE_0;

#define UI_KEYCODE_LETTER(x) (UI_KEYCODE_A + (x) - 'A')
#define UI_KEYCODE_DIGIT(x) (UI_KEYCODE_0 + (x) - '0')
#define UI_KEYCODE_FKEY(x) (UI_KEYCODE_F1 + (x) - 1)

typedef struct UIElement {
#define UI_ELEMENT_V_FILL (1 << 16)
#define UI_ELEMENT_H_FILL (1 << 17)
#define UI_ELEMENT_WINDOW (1 << 18)
#define UI_ELEMENT_PARENT_PUSH (1 << 19)
#define UI_ELEMENT_TAB_STOP (1 << 20)
#define UI_ELEMENT_NON_CLIENT (1 << 21) // Don't destroy in UIElementDestroyDescendents, like scroll bars.
#define UI_ELEMENT_DISABLED (1 << 22) // Don't receive input events.

#define UI_ELEMENT_HIDE (1 << 29)
#define UI_ELEMENT_DESTROY (1 << 30)
#define UI_ELEMENT_DESTROY_DESCENDENT (1 << 31)

	uint32_t flags; // First 16 bits are element specific.

	struct UIElement *parent;
	struct UIElement *next;
	struct UIElement *children;
	struct UIWindow *window;

	UIRectangle bounds, clip;
	
	void *cp; // Context pointer (for user).

	int (*messageClass)(struct UIElement *element, UIMessage message, int di /* data integer */, void *dp /* data pointer */);
	int (*messageUser)(struct UIElement *element, UIMessage message, int di, void *dp);

#ifdef UI_DEBUG
	const char *cClassName;
	int id;
#endif
} UIElement;

#define UI_SHORTCUT(code, ctrl, shift, alt, invoke, cp) ((UIShortcut) { (code), (ctrl), (shift), (alt), (invoke), (cp) })

typedef struct UIWindow {
#define UI_WINDOW_MENU (1 << 0)
#define UI_WINDOW_INSPECTOR (1 << 1)
#define UI_WINDOW_CENTER_IN_OWNER (1 << 2)
#define UI_WINDOW_MAXIMIZE (1 << 3)

	UIElement e;

	UIElement *dialog;

	UIShortcut *shortcuts;
	size_t shortcutCount, shortcutAllocated;

	float scale;

	uint32_t *bits;
	int width, height;
	struct UIWindow *next;

	UIElement *hovered, *pressed, *focused, *dialogOldFocus;
	int pressedButton;

	int cursorX, cursorY;
	int cursorStyle;

	// Set when a textbox is modified. 
	// Useful for tracking whether changes to the loaded document have been saved.
	bool textboxModifiedFlag; 

	bool ctrl, shift, alt;

	UIRectangle updateRegion;

#ifdef UI_DEBUG
	float lastFullFillCount;
#endif

#ifdef UI_LINUX
	Window window;
	XImage *image;
	XIC xic;
	unsigned ctrlCode, shiftCode, altCode;
	Window dragSource;
#endif

#ifdef UI_WINDOWS
	HWND hwnd;
	bool trackingLeave;
#endif

#ifdef UI_ESSENCE
	EsWindow *window;
	EsElement *canvas;
	int cursor;
#endif
} UIWindow;

typedef struct UIPanel {
#define UI_PANEL_HORIZONTAL (1 << 0)
#define UI_PANEL_GRAY (1 << 2)
#define UI_PANEL_WHITE (1 << 3)
#define UI_PANEL_EXPAND (1 << 4)
#define UI_PANEL_MEDIUM_SPACING (1 << 5)
#define UI_PANEL_SMALL_SPACING (1 << 6)
#define UI_PANEL_SCROLL (1 << 7)
#define UI_PANEL_BORDER (1 << 8)
	UIElement e;
	struct UIScrollBar *scrollBar;
	UIRectangle border;
	int gap;
} UIPanel;

typedef struct UIButton {
#define UI_BUTTON_SMALL (1 << 0)
#define UI_BUTTON_MENU_ITEM (1 << 1)
#define UI_BUTTON_CAN_FOCUS (1 << 2)
#define UI_BUTTON_DROP_DOWN (1 << 3)
#define UI_BUTTON_CHECKED (1 << 15)
	UIElement e;
	char *label;
	ptrdiff_t labelBytes;
	void (*invoke)(void *cp);
} UIButton;

typedef struct UICheckbox {
#define UI_CHECKBOX_ALLOW_INDETERMINATE (1 << 0)
	UIElement e;
#define UI_CHECK_UNCHECKED (0)
#define UI_CHECK_CHECKED (1)
#define UI_CHECK_INDETERMINATE (2)
	uint8_t check;
	char *label;
	ptrdiff_t labelBytes;
	void (*invoke)(void *cp);
} UICheckbox;

typedef struct UILabel {
	UIElement e;
	char *label;
	ptrdiff_t labelBytes;
} UILabel;

typedef struct UISpacer {
#define UI_SPACER_LINE (1 << 0)
	UIElement e;
	int width, height;
} UISpacer;

typedef struct UISplitPane {
#define UI_SPLIT_PANE_VERTICAL (1 << 0)
	UIElement e;
	float weight;
} UISplitPane;

typedef struct UITabPane {
	UIElement e;
	char *tabs;
	int active;
} UITabPane;

typedef struct UIScrollBar {
#define UI_SCROLL_BAR_HORIZONTAL (1 << 0)
	UIElement e;
	int64_t maximum, page;
	int64_t dragOffset;
	double position;
	uint64_t lastAnimateTime;
	bool inDrag, horizontal;
} UIScrollBar;

typedef struct UICodeLine {
	int offset, bytes;
} UICodeLine;

typedef struct UICode {
#define UI_CODE_NO_MARGIN (1 << 0)
	UIElement e;
	UIScrollBar *vScroll;
	UICodeLine *lines;
	UIFont *font;
	int lineCount, focused;
	bool moveScrollToFocusNextLayout;
	char *content;
	size_t contentBytes;
	int tabSize;
} UICode;

typedef struct UIGauge {
	UIElement e;
	float position;
} UIGauge;

typedef struct UITable {
	UIElement e;
	UIScrollBar *vScroll;
	int itemCount;
	char *columns;
	int *columnWidths, columnCount, columnHighlight;
} UITable;

typedef struct UITextbox {
	UIElement e;
	char *string;
	ptrdiff_t bytes;
	int carets[2];
	int scroll;
	bool rejectNextKey;
} UITextbox;

#define UI_MENU_PLACE_ABOVE (1 << 0)
#define UI_MENU_NO_SCROLL (1 << 1)
#ifdef UI_ESSENCE
typedef EsMenu UIMenu;
#else
typedef struct UIMenu {
	UIElement e;
	int pointX, pointY;
	UIScrollBar *vScroll;
} UIMenu;
#endif

typedef struct UISlider {
	UIElement e;
	float position;
	int steps;
} UISlider;

typedef struct UIColorPicker {
#define UI_COLOR_PICKER_HAS_OPACITY (1 << 0)
	UIElement e;
	float hue, saturation, value, opacity;
} UIColorPicker;

typedef struct UIMDIClient {
#define UI_MDI_CLIENT_TRANSPARENT (1 << 0)
	UIElement e;
	struct UIMDIChild *active;
	int cascade;
} UIMDIClient;

typedef struct UIMDIChild {
#define UI_MDI_CHILD_CLOSE_BUTTON (1 << 0)
	UIElement e;
	UIRectangle bounds;
	char *title;
	ptrdiff_t titleBytes;
	int dragHitTest;
	UIRectangle dragOffset;
	struct UIMDIChild *previous;
} UIMDIChild;

typedef struct UIExpandPane {
	UIElement e;
	UIButton *button;
	UIPanel *panel;
	bool expanded;
} UIExpandPane;

typedef struct UIImageDisplay {
#define UI_IMAGE_DISPLAY_INTERACTIVE (1 << 0)
#define _UI_IMAGE_DISPLAY_ZOOM_FIT (1 << 1)

	UIElement e;
	uint32_t *bits;
	int width, height;
	float panX, panY, zoom;
	
	// Internals:
	int previousWidth, previousHeight;
	int previousPanPointX, previousPanPointY;
} UIImageDisplay;

void UIInitialise();
int UIMessageLoop();

UIElement *UIElementCreate(size_t bytes, UIElement *parent, uint32_t flags, 
	int (*messageClass)(UIElement *, UIMessage, int, void *), const char *cClassName);

UIButton *UIButtonCreate(UIElement *parent, uint32_t flags, const char *label, ptrdiff_t labelBytes);
UICheckbox *UICheckboxCreate(UIElement *parent, uint32_t flags, const char *label, ptrdiff_t labelBytes);
UIColorPicker *UIColorPickerCreate(UIElement *parent, uint32_t flags);
UIExpandPane *UIExpandPaneCreate(UIElement *parent, uint32_t flags, const char *label, ptrdiff_t labelBytes, uint32_t panelFlags);
UIGauge *UIGaugeCreate(UIElement *parent, uint32_t flags);
UIMDIClient *UIMDIClientCreate(UIElement *parent, uint32_t flags);
UIMDIChild *UIMDIChildCreate(UIElement *parent, uint32_t flags, UIRectangle initialBounds, const char *title, ptrdiff_t titleBytes);
UIPanel *UIPanelCreate(UIElement *parent, uint32_t flags);
UIScrollBar *UIScrollBarCreate(UIElement *parent, uint32_t flags);
UISlider *UISliderCreate(UIElement *parent, uint32_t flags);
UISpacer *UISpacerCreate(UIElement *parent, uint32_t flags, int width, int height);
UISplitPane *UISplitPaneCreate(UIElement *parent, uint32_t flags, float weight);
UITabPane *UITabPaneCreate(UIElement *parent, uint32_t flags, const char *tabs /* separate with \t, terminate with \0 */);

UILabel *UILabelCreate(UIElement *parent, uint32_t flags, const char *label, ptrdiff_t labelBytes);
void UILabelSetContent(UILabel *code, const char *content, ptrdiff_t byteCount);

UIImageDisplay *UIImageDisplayCreate(UIElement *parent, uint32_t flags, uint32_t *bits, size_t width, size_t height, size_t stride);
void UIImageDisplaySetContent(UIImageDisplay *display, uint32_t *bits, size_t width, size_t height, size_t stride);

UIWindow *UIWindowCreate(UIWindow *owner, uint32_t flags, const char *cTitle, int width, int height);
void UIWindowRegisterShortcut(UIWindow *window, UIShortcut shortcut);
void UIWindowPostMessage(UIWindow *window, UIMessage message, void *dp); // Thread-safe.
void UIWindowPack(UIWindow *window, int width); // Change the size of the window to best match its contents.

const char *UIDialogShow(UIWindow *window, uint32_t flags, const char *format, ...);

UIMenu *UIMenuCreate(UIElement *parent, uint32_t flags);
void UIMenuAddItem(UIMenu *menu, uint32_t flags, const char *label, ptrdiff_t labelBytes, void (*invoke)(void *cp), void *cp);
void UIMenuShow(UIMenu *menu);

UITextbox *UITextboxCreate(UIElement *parent, uint32_t flags);
void UITextboxReplace(UITextbox *textbox, const char *text, ptrdiff_t bytes, bool sendChangedMessage);
void UITextboxClear(UITextbox *textbox, bool sendChangedMessage);
void UITextboxMoveCaret(UITextbox *textbox, bool backward, bool word);

UITable *UITableCreate(UIElement *parent, uint32_t flags, const char *columns /* separate with \t, terminate with \0 */);
int UITableHitTest(UITable *table, int x, int y); // Returns item index. Returns -1 if not on an item.
int UITableHeaderHitTest(UITable *table, int x, int y); // Returns column index or -1.
bool UITableEnsureVisible(UITable *table, int index); // Returns false if the item was already visible.
void UITableResizeColumns(UITable *table);

UICode *UICodeCreate(UIElement *parent, uint32_t flags);
void UICodeFocusLine(UICode *code, int index); // Line numbers are 1-indexed!!
int UICodeHitTest(UICode *code, int x, int y); // Returns line number; negates if in margin. Returns 0 if not on a line.
void UICodeInsertContent(UICode *code, const char *content, ptrdiff_t byteCount, bool replace);

void UIDrawBlock(UIPainter *painter, UIRectangle rectangle, uint32_t color);
void UIDrawInvert(UIPainter *painter, UIRectangle rectangle);
bool UIDrawLine(UIPainter *painter, int x0, int y0, int x1, int y1, uint32_t color); // Returns false if the line was not visible.
void UIDrawGlyph(UIPainter *painter, int x, int y, int c, uint32_t color);
void UIDrawRectangle(UIPainter *painter, UIRectangle r, uint32_t mainColor, uint32_t borderColor, UIRectangle borderSize);
void UIDrawBorder(UIPainter *painter, UIRectangle r, uint32_t borderColor, UIRectangle borderSize);
void UIDrawString(UIPainter *painter, UIRectangle r, const char *string, ptrdiff_t bytes, uint32_t color, int align, UIStringSelection *selection);
int UIDrawStringHighlighted(UIPainter *painter, UIRectangle r, const char *string, ptrdiff_t bytes, int tabSize);

int UIMeasureStringWidth(const char *string, ptrdiff_t bytes);
int UIMeasureStringHeight();

uint64_t UIAnimateClock(); // In ms.

bool UIElementAnimate(UIElement *element, bool stop);
void UIElementDestroy(UIElement *element);
void UIElementDestroyDescendents(UIElement *element);
UIElement *UIElementFindByPoint(UIElement *element, int x, int y);
void UIElementFocus(UIElement *element);
UIRectangle UIElementScreenBounds(UIElement *element); // Returns bounds of element in same coordinate system as used by UIWindowCreate.
void UIElementRefresh(UIElement *element);
void UIElementRepaint(UIElement *element, UIRectangle *region);
void UIElementMove(UIElement *element, UIRectangle bounds, bool alwaysLayout);
int UIElementMessage(UIElement *element, UIMessage message, int di, void *dp);
void UIElementChangeParent(UIElement *element, UIElement *newParent, UIElement *insertBefore); // Set insertBefore to null to insert at the end.

UIElement *UIParentPush(UIElement *element);
UIElement *UIParentPop();

UIRectangle UIRectangleIntersection(UIRectangle a, UIRectangle b);
UIRectangle UIRectangleBounding(UIRectangle a, UIRectangle b);
UIRectangle UIRectangleAdd(UIRectangle a, UIRectangle b);
UIRectangle UIRectangleTranslate(UIRectangle a, UIRectangle b);
bool UIRectangleEquals(UIRectangle a, UIRectangle b);
bool UIRectangleContains(UIRectangle a, int x, int y);

bool UIColorToHSV(uint32_t rgb, float *hue, float *saturation, float *value);
void UIColorToRGB(float hue, float saturation, float value, uint32_t *rgb);

char *UIStringCopy(const char *in, ptrdiff_t inBytes);

UIFont *UIFontCreate(const char *cPath, uint32_t size);
UIFont *UIFontActivate(UIFont *font); // Returns the previously active font.

#ifdef UI_DEBUG
void UIInspectorLog(const char *cFormat, ...);
#endif

#ifdef UI_IMPLEMENTATION

struct {
	UIWindow *windows;
	UIElement *animating;
	UITheme theme;

	UIElement *parentStack[16];
	int parentStackCount;

	bool quit;
	const char *dialogResult;
	UIElement *dialogOldFocus;

	UIFont *activeFont;

#ifdef UI_DEBUG
	UIWindow *inspector;
	UITable *inspectorTable;
	UIWindow *inspectorTarget;
	UICode *inspectorLog;
#endif

#ifdef UI_LINUX
	Display *display;
	Visual *visual;
	XIM xim;
	Atom windowClosedID, primaryID, uriListID, plainTextID;
	Atom dndEnterID, dndPositionID, dndStatusID, dndActionCopyID, dndDropID, dndSelectionID, dndFinishedID, dndAwareID;
	Cursor cursors[UI_CURSOR_COUNT];
#endif

#ifdef UI_WINDOWS
	HCURSOR cursors[UI_CURSOR_COUNT];
	HANDLE heap;
	bool assertionFailure;
#endif

#ifdef UI_ESSENCE
	EsInstance *instance;

	void *menuData[256]; // HACK This limits the number of menu items to 128.
	uintptr_t menuIndex;
#endif

#ifdef UI_FREETYPE
	FT_Library ft;
#endif
} ui;

UITheme _uiThemeClassic = {
	.panel1 = 0xFFF0F0F0,
	.panel2 = 0xFFFFFFFF,
	.selected = 0xFF94BEFE,
	.border = 0xFF404040,

	.text = 0xFF000000,
	.textDisabled = 0xFF404040,
	.textSelected = 0xFF000000,

	.buttonNormal = 0xFFE0E0E0,
	.buttonHovered = 0xFFF0F0F0,
	.buttonPressed = 0xFFA0A0A0,
	.buttonDisabled = 0xFFF0F0F0,

	.textboxNormal = 0xFFF8F8F8,
	.textboxFocused = 0xFFFFFFFF,

	.codeFocused = 0xFFE0E0E0,
	.codeBackground = 0xFFFFFFFF,
	.codeDefault = 0xFF000000,
	.codeComment = 0xFFA11F20,
	.codeString = 0xFF037E01,
	.codeNumber = 0xFF213EF1,
	.codeOperator = 0xFF7F0480,
	.codePreprocessor = 0xFF545D70,
};

UITheme _uiThemeDark = {
	.panel1 = 0xFF252B31,
	.panel2 = 0xFF14181E,
	.selected = 0xFF94BEFE,
	.border = 0xFF000000,

	.text = 0xFFFFFFFF,
	.textDisabled = 0xFF787D81,
	.textSelected = 0xFF000000,

	.buttonNormal = 0xFF383D41,
	.buttonHovered = 0xFF4B5874,
	.buttonPressed = 0xFF0D0D0F,
	.buttonDisabled = 0xFF1B1F23,

	.textboxNormal = 0xFF31353C,
	.textboxFocused = 0xFF4D4D59,

	.codeFocused = 0xFF505055,
	.codeBackground = 0xFF212126,
	.codeDefault = 0xFFFFFFFF,
	.codeComment = 0xFFB4B4B4,
	.codeString = 0xFFF5DDD1,
	.codeNumber = 0xFFC3F5D3,
	.codeOperator = 0xFFF5D499,
	.codePreprocessor = 0xFFF5F3D1,
};

// Taken from https://commons.wikimedia.org/wiki/File:Codepage-437.png
// Public domain.

const uint64_t _uiFont[] = {
	0x0000000000000000UL, 0x0000000000000000UL, 0xBD8181A5817E0000UL, 0x000000007E818199UL, 0xC3FFFFDBFF7E0000UL, 0x000000007EFFFFE7UL, 0x7F7F7F3600000000UL, 0x00000000081C3E7FUL, 
	0x7F3E1C0800000000UL, 0x0000000000081C3EUL, 0xE7E73C3C18000000UL, 0x000000003C1818E7UL, 0xFFFF7E3C18000000UL, 0x000000003C18187EUL, 0x3C18000000000000UL, 0x000000000000183CUL, 
	0xC3E7FFFFFFFFFFFFUL, 0xFFFFFFFFFFFFE7C3UL, 0x42663C0000000000UL, 0x00000000003C6642UL, 0xBD99C3FFFFFFFFFFUL, 0xFFFFFFFFFFC399BDUL, 0x331E4C5870780000UL, 0x000000001E333333UL, 
	0x3C666666663C0000UL, 0x0000000018187E18UL, 0x0C0C0CFCCCFC0000UL, 0x00000000070F0E0CUL, 0xC6C6C6FEC6FE0000UL, 0x0000000367E7E6C6UL, 0xE73CDB1818000000UL, 0x000000001818DB3CUL, 
	0x1F7F1F0F07030100UL, 0x000000000103070FUL, 0x7C7F7C7870604000UL, 0x0000000040607078UL, 0x1818187E3C180000UL, 0x0000000000183C7EUL, 0x6666666666660000UL, 0x0000000066660066UL, 
	0xD8DEDBDBDBFE0000UL, 0x00000000D8D8D8D8UL, 0x6363361C06633E00UL, 0x0000003E63301C36UL, 0x0000000000000000UL, 0x000000007F7F7F7FUL, 0x1818187E3C180000UL, 0x000000007E183C7EUL, 
	0x1818187E3C180000UL, 0x0000000018181818UL, 0x1818181818180000UL, 0x00000000183C7E18UL, 0x7F30180000000000UL, 0x0000000000001830UL, 0x7F060C0000000000UL, 0x0000000000000C06UL, 
	0x0303000000000000UL, 0x0000000000007F03UL, 0xFF66240000000000UL, 0x0000000000002466UL, 0x3E1C1C0800000000UL, 0x00000000007F7F3EUL, 0x3E3E7F7F00000000UL, 0x0000000000081C1CUL, 
	0x0000000000000000UL, 0x0000000000000000UL, 0x18183C3C3C180000UL, 0x0000000018180018UL, 0x0000002466666600UL, 0x0000000000000000UL, 0x36367F3636000000UL, 0x0000000036367F36UL, 
	0x603E0343633E1818UL, 0x000018183E636160UL, 0x1830634300000000UL, 0x000000006163060CUL, 0x3B6E1C36361C0000UL, 0x000000006E333333UL, 0x000000060C0C0C00UL, 0x0000000000000000UL, 
	0x0C0C0C0C18300000UL, 0x0000000030180C0CUL, 0x30303030180C0000UL, 0x000000000C183030UL, 0xFF3C660000000000UL, 0x000000000000663CUL, 0x7E18180000000000UL, 0x0000000000001818UL, 
	0x0000000000000000UL, 0x0000000C18181800UL, 0x7F00000000000000UL, 0x0000000000000000UL, 0x0000000000000000UL, 0x0000000018180000UL, 0x1830604000000000UL, 0x000000000103060CUL, 
	0xDBDBC3C3663C0000UL, 0x000000003C66C3C3UL, 0x1818181E1C180000UL, 0x000000007E181818UL, 0x0C183060633E0000UL, 0x000000007F630306UL, 0x603C6060633E0000UL, 0x000000003E636060UL, 
	0x7F33363C38300000UL, 0x0000000078303030UL, 0x603F0303037F0000UL, 0x000000003E636060UL, 0x633F0303061C0000UL, 0x000000003E636363UL, 0x18306060637F0000UL, 0x000000000C0C0C0CUL, 
	0x633E6363633E0000UL, 0x000000003E636363UL, 0x607E6363633E0000UL, 0x000000001E306060UL, 0x0000181800000000UL, 0x0000000000181800UL, 0x0000181800000000UL, 0x000000000C181800UL, 
	0x060C183060000000UL, 0x000000006030180CUL, 0x00007E0000000000UL, 0x000000000000007EUL, 0x6030180C06000000UL, 0x00000000060C1830UL, 0x18183063633E0000UL, 0x0000000018180018UL, 
	0x7B7B63633E000000UL, 0x000000003E033B7BUL, 0x7F6363361C080000UL, 0x0000000063636363UL, 0x663E6666663F0000UL, 0x000000003F666666UL, 0x03030343663C0000UL, 0x000000003C664303UL, 
	0x66666666361F0000UL, 0x000000001F366666UL, 0x161E1646667F0000UL, 0x000000007F664606UL, 0x161E1646667F0000UL, 0x000000000F060606UL, 0x7B030343663C0000UL, 0x000000005C666363UL, 
	0x637F636363630000UL, 0x0000000063636363UL, 0x18181818183C0000UL, 0x000000003C181818UL, 0x3030303030780000UL, 0x000000001E333333UL, 0x1E1E366666670000UL, 0x0000000067666636UL, 
	0x06060606060F0000UL, 0x000000007F664606UL, 0xC3DBFFFFE7C30000UL, 0x00000000C3C3C3C3UL, 0x737B7F6F67630000UL, 0x0000000063636363UL, 0x63636363633E0000UL, 0x000000003E636363UL, 
	0x063E6666663F0000UL, 0x000000000F060606UL, 0x63636363633E0000UL, 0x000070303E7B6B63UL, 0x363E6666663F0000UL, 0x0000000067666666UL, 0x301C0663633E0000UL, 0x000000003E636360UL, 
	0x18181899DBFF0000UL, 0x000000003C181818UL, 0x6363636363630000UL, 0x000000003E636363UL, 0xC3C3C3C3C3C30000UL, 0x00000000183C66C3UL, 0xDBC3C3C3C3C30000UL, 0x000000006666FFDBUL, 
	0x18183C66C3C30000UL, 0x00000000C3C3663CUL, 0x183C66C3C3C30000UL, 0x000000003C181818UL, 0x0C183061C3FF0000UL, 0x00000000FFC38306UL, 0x0C0C0C0C0C3C0000UL, 0x000000003C0C0C0CUL, 
	0x1C0E070301000000UL, 0x0000000040607038UL, 0x30303030303C0000UL, 0x000000003C303030UL, 0x0000000063361C08UL, 0x0000000000000000UL, 0x0000000000000000UL, 0x0000FF0000000000UL, 
	0x0000000000180C0CUL, 0x0000000000000000UL, 0x3E301E0000000000UL, 0x000000006E333333UL, 0x66361E0606070000UL, 0x000000003E666666UL, 0x03633E0000000000UL, 0x000000003E630303UL, 
	0x33363C3030380000UL, 0x000000006E333333UL, 0x7F633E0000000000UL, 0x000000003E630303UL, 0x060F0626361C0000UL, 0x000000000F060606UL, 0x33336E0000000000UL, 0x001E33303E333333UL, 
	0x666E360606070000UL, 0x0000000067666666UL, 0x18181C0018180000UL, 0x000000003C181818UL, 0x6060700060600000UL, 0x003C666660606060UL, 0x1E36660606070000UL, 0x000000006766361EUL, 
	0x18181818181C0000UL, 0x000000003C181818UL, 0xDBFF670000000000UL, 0x00000000DBDBDBDBUL, 0x66663B0000000000UL, 0x0000000066666666UL, 0x63633E0000000000UL, 0x000000003E636363UL, 
	0x66663B0000000000UL, 0x000F06063E666666UL, 0x33336E0000000000UL, 0x007830303E333333UL, 0x666E3B0000000000UL, 0x000000000F060606UL, 0x06633E0000000000UL, 0x000000003E63301CUL, 
	0x0C0C3F0C0C080000UL, 0x00000000386C0C0CUL, 0x3333330000000000UL, 0x000000006E333333UL, 0xC3C3C30000000000UL, 0x00000000183C66C3UL, 0xC3C3C30000000000UL, 0x0000000066FFDBDBUL, 
	0x3C66C30000000000UL, 0x00000000C3663C18UL, 0x6363630000000000UL, 0x001F30607E636363UL, 0x18337F0000000000UL, 0x000000007F63060CUL, 0x180E181818700000UL, 0x0000000070181818UL, 
	0x1800181818180000UL, 0x0000000018181818UL, 0x18701818180E0000UL, 0x000000000E181818UL, 0x000000003B6E0000UL, 0x0000000000000000UL, 0x63361C0800000000UL, 0x00000000007F6363UL, 
};

void _UIWindowEndPaint(UIWindow *window, UIPainter *painter);
void _UIWindowSetCursor(UIWindow *window, int cursor);
void _UIWindowGetScreenPosition(UIWindow *window, int *x, int *y);
void _UIWindowSetPressed(UIWindow *window, UIElement *element, int button);
bool _UIMessageLoopSingle(int *result);
void _UIInspectorRefresh();
void _UIUpdate();

#ifdef UI_WINDOWS
void *_UIHeapReAlloc(void *pointer, size_t size);
#endif

UIRectangle UIRectangleIntersection(UIRectangle a, UIRectangle b) {
	if (a.l < b.l) a.l = b.l;
	if (a.t < b.t) a.t = b.t;
	if (a.r > b.r) a.r = b.r;
	if (a.b > b.b) a.b = b.b;
	return a;
}

UIRectangle UIRectangleBounding(UIRectangle a, UIRectangle b) {
	if (a.l > b.l) a.l = b.l;
	if (a.t > b.t) a.t = b.t;
	if (a.r < b.r) a.r = b.r;
	if (a.b < b.b) a.b = b.b;
	return a;
}

UIRectangle UIRectangleAdd(UIRectangle a, UIRectangle b) {
	a.l += b.l;
	a.t += b.t;
	a.r += b.r;
	a.b += b.b;
	return a;
}

UIRectangle UIRectangleTranslate(UIRectangle a, UIRectangle b) {
	a.l += b.l;
	a.t += b.t;
	a.r += b.l;
	a.b += b.t;
	return a;
}

bool UIRectangleEquals(UIRectangle a, UIRectangle b) {
	return a.l == b.l && a.r == b.r && a.t == b.t && a.b == b.b;
}

bool UIRectangleContains(UIRectangle a, int x, int y) {
	return a.l <= x && a.r > x && a.t <= y && a.b > y;
}

#include <xmmintrin.h>

typedef union _UIConvertFloatInteger {
	float f;
	uint32_t i;
} _UIConvertFloatInteger;

float _UIFloorFloat(float x) {
	_UIConvertFloatInteger convert = {x};
	uint32_t sign = convert.i & 0x80000000;
	int exponent = (int) ((convert.i >> 23) & 0xFF) - 0x7F;

	if (exponent >= 23) {
		// There aren't any bits representing a fractional part.
	} else if (exponent >= 0) {
		// Positive exponent.
		uint32_t mask = 0x7FFFFF >> exponent;
		if (!(mask & convert.i)) return x; // Already an integer.
		if (sign) convert.i += mask;
		convert.i &= ~mask; // Mask out the fractional bits.
	} else if (exponent < 0) {
		// Negative exponent.
		return sign ? -1.0 : 0.0;
	}

	return convert.f;
}

float _UISquareRootFloat(float x) {
	float result[4];
	_mm_storeu_ps(result, _mm_sqrt_ps(_mm_set_ps(0, 0, 0, x)));
	return result[0];
}

#define _F(x) (((_UIConvertFloatInteger) { .i = (x) }).f)

float _UIArcTanFloatI(float x) {
	float x2 = x * x;
	return x * (_F(0x3F7FFFF8) + x2 * (_F(0xBEAAA53C) + x2 * (_F(0x3E4BC990) + x2 * (_F(0xBE084A60) + x2 * _F(0x3D8864B0)))));
}

float _UISinFloatI(float x) {
	float x2 = x * x;
	return x * (_F(0x3F800000) + x2 * (_F(0xBE2AAAA0) + x2 * (_F(0x3C0882C0) + x2 * _F(0xB94C6000))));
}

float _UICosFloatI(float x) {
	float x2 = x * x;
	return _F(0x3F800000) + x2 * (_F(0xBEFFFFDA) + x2 * (_F(0x3D2A9F60) + x2 * _F(0xBAB22C00)));
}

#undef _F

float _UISinFloat(float x) {
	bool negate = false;
	if (x < 0) { x = -x; negate = true; }
	x -= 2 * 3.141592654f * _UIFloorFloat(x / (2 * 3.141592654f));
	if (x < 3.141592654f / 2) {}
	else if (x < 3.141592654f) { x = 3.141592654f - x; }
	else if (x < 3 * 3.141592654f / 2) { x = x - 3.141592654f; negate = !negate; }
	else { x = 3.141592654f * 2 - x; negate = !negate; }
	float y = x < 3.141592654f / 4 ? _UISinFloatI(x) : _UICosFloatI(3.141592654f / 2 - x);
	return negate ? -y : y;
}

float _UICosFloat(float x) {
	return _UISinFloat(3.141592654f / 2 - x);
}

float _UIArcTanFloat(float x) {
	bool negate = false, reciprocalTaken = false;
	if (x < 0) { x = -x; negate = true; }
	if (x > 1) { x = 1 / x; reciprocalTaken = true; }
	float y = x < 0.5f ? _UIArcTanFloatI(x) : (0.463647609f + _UIArcTanFloatI((2 * x - 1) / (2 + x)));
	if (reciprocalTaken) { y = 3.141592654f / 2 - y; }
	return negate ? -y : y;
}

float _UIArcTan2Float(float y, float x) {
	if (x == 0) return y > 0 ? 3.141592654f / 2 : -3.141592654f / 2;
	else if (x > 0) return _UIArcTanFloat(y / x);
	else if (y >= 0) return 3.141592654f + _UIArcTanFloat(y / x);
	else return -3.141592654f + _UIArcTanFloat(y / x);
}

float _UILinearMap(float value, float inFrom, float inTo, float outFrom, float outTo) {
	float inRange = inTo - inFrom, outRange = outTo - outFrom;
	float normalisedValue = (value - inFrom) / inRange;
	return normalisedValue * outRange + outFrom;
}

bool UIColorToHSV(uint32_t rgb, float *hue, float *saturation, float *value) {
	float r = UI_COLOR_RED_F(rgb);
	float g = UI_COLOR_GREEN_F(rgb);
	float b = UI_COLOR_BLUE_F(rgb);

	float maximum = (r > g && r > b) ? r : (g > b ? g : b),
	      minimum = (r < g && r < b) ? r : (g < b ? g : b),
	      difference = maximum - minimum;
	*value = maximum;

	if (!difference) {
		*saturation = 0;
		return false;
	} else {
		if (r == maximum) *hue = (g - b) / difference + 0;
		if (g == maximum) *hue = (b - r) / difference + 2;
		if (b == maximum) *hue = (r - g) / difference + 4;
		if (*hue < 0) *hue += 6;
		*saturation = difference / maximum;
		return true;
	}
}

void UIColorToRGB(float h, float s, float v, uint32_t *rgb) {
	float r, g, b;

	if (!s) {
		r = g = b = v;
	} else {
		int h0 = ((int) h) % 6;
		float f = h - _UIFloorFloat(h);
		float x = v * (1 - s), y = v * (1 - s * f), z = v * (1 - s * (1 - f));

		switch (h0) {
			case 0:  r = v, g = z, b = x; break;
			case 1:  r = y, g = v, b = x; break;
			case 2:  r = x, g = v, b = z; break;
			case 3:  r = x, g = y, b = v; break;
			case 4:  r = z, g = x, b = v; break;
			default: r = v, g = x, b = y; break;
		}
	}

	*rgb = UI_COLOR_FROM_FLOAT(r, g, b);
}

void UIElementRefresh(UIElement *element) {
	UIElementMessage(element, UI_MSG_LAYOUT, 0, 0);
	UIElementRepaint(element, NULL);
}

void UIElementRepaint(UIElement *element, UIRectangle *region) {
	if (!region) {
		region = &element->bounds;
	}

	UIRectangle r = UIRectangleIntersection(*region, element->clip);

	if (!UI_RECT_VALID(r)) {
		return;
	}

	if (UI_RECT_VALID(element->window->updateRegion)) {
		element->window->updateRegion = UIRectangleBounding(element->window->updateRegion, r);
	} else {
		element->window->updateRegion = r;
	}
}

bool UIElementAnimate(UIElement *element, bool stop) {
	if (stop) {
		if (ui.animating != element) {
			return false;
		}

		ui.animating = NULL;
	} else {
		if (ui.animating && ui.animating != element) {
			return false;
		}

		ui.animating = element;
	}

	return true;
}

uint64_t UIAnimateClock() {
	return (uint64_t) UI_CLOCK() * 1000 / UI_CLOCKS_PER_SECOND;
}

void _UIElementDestroyDescendents(UIElement *element, bool topLevel) {
	UIElement *child = element->children;

	while (child) {
		if (!topLevel || (~child->flags & UI_ELEMENT_NON_CLIENT)) {
			UIElementDestroy(child);
		}

		child = child->next;
	}

#ifdef UI_DEBUG
	_UIInspectorRefresh();
#endif
}

void UIElementDestroyDescendents(UIElement *element) {
	_UIElementDestroyDescendents(element, true);
}

void UIElementDestroy(UIElement *element) {
	if (element->flags & UI_ELEMENT_DESTROY) {
		return;
	}

	element->flags |= UI_ELEMENT_DESTROY | UI_ELEMENT_HIDE;

	UIElement *ancestor = element->parent;

	while (ancestor) {
		ancestor->flags |= UI_ELEMENT_DESTROY_DESCENDENT;
		ancestor = ancestor->parent;
	}

	_UIElementDestroyDescendents(element, false);
}

void UIDrawBlock(UIPainter *painter, UIRectangle rectangle, uint32_t color) {
	rectangle = UIRectangleIntersection(painter->clip, rectangle);

	if (!UI_RECT_VALID(rectangle)) {
		return;
	}

#ifdef UI_SSE2
	__m128i color4 = _mm_set_epi32(color, color, color, color);
#endif

	for (int line = rectangle.t; line < rectangle.b; line++) {
		uint32_t *bits = painter->bits + line * painter->width + rectangle.l;
		int count = UI_RECT_WIDTH(rectangle);

#ifdef UI_SSE2
		while (count >= 4) {
			_mm_storeu_si128((__m128i *) bits, color4);
			bits += 4;
			count -= 4;
		} 
#endif

		while (count--) {
			*bits++ = color;
		}
	}

#ifdef UI_DEBUG
	painter->fillCount += UI_RECT_WIDTH(rectangle) * UI_RECT_HEIGHT(rectangle);
#endif
}

bool UIDrawLine(UIPainter *painter, int x0, int y0, int x1, int y1, uint32_t color) {
	// Apply the clip.

	UIRectangle c = painter->clip;
	if (!UI_RECT_VALID(c)) return false;
	int dx = x1 - x0, dy = y1 - y0;
	const int p[4] = { -dx, dx, -dy, dy };
	const int q[4] = { x0 - c.l, c.r - 1 - x0, y0 - c.t, c.b - 1 - y0 };
	float t0 = 0.0f, t1 = 1.0f; // How far along the line the points end up.

	for (int i = 0; i < 4; i++) {
		if (!p[i] && q[i] < 0) return false;
		float r = (float) q[i] / p[i];
		if (p[i] < 0 && r > t1) return false;
		if (p[i] > 0 && r < t0) return false;
		if (p[i] < 0 && r > t0) t0 = r;
		if (p[i] > 0 && r < t1) t1 = r;
	}

	x1 = x0 + t1 * dx, y1 = y0 + t1 * dy;
	x0 += t0 * dx, y0 += t0 * dy;

	// Calculate the delta X and delta Y.

	if (y1 < y0) {
		int t;
		t = x0, x0 = x1, x1 = t;
		t = y0, y0 = y1, y1 = t;
	}

	dx = x1 - x0, dy = y1 - y0;
	int dxs = dx < 0 ? -1 : 1;
	if (dx < 0) dx = -dx;

	// Draw the line using Bresenham's line algorithm.

	uint32_t *bits = painter->bits + y0 * painter->width + x0;

	if (dy * dy < dx * dx) {
		int m = 2 * dy - dx;

		for (int i = 0; i < dx; i++, bits += dxs) {
			*bits = color;
			if (m > 0) bits += painter->width, m -= 2 * dx;
			m += 2 * dy;
		}
	} else {
		int m = 2 * dx - dy;

		for (int i = 0; i < dy; i++, bits += painter->width) {
			*bits = color;
			if (m > 0) bits += dxs, m -= 2 * dy;
			m += 2 * dx;
		}
	}

	return true;
}

void UIDrawInvert(UIPainter *painter, UIRectangle rectangle) {
	rectangle = UIRectangleIntersection(painter->clip, rectangle);

	if (!UI_RECT_VALID(rectangle)) {
		return;
	}

	for (int line = rectangle.t; line < rectangle.b; line++) {
		uint32_t *bits = painter->bits + line * painter->width + rectangle.l;
		int count = UI_RECT_WIDTH(rectangle);

		while (count--) {
			uint32_t in = *bits;
			*bits = in ^ 0xFFFFFF;
			bits++;
		}
	}
}

void UIDrawGlyph(UIPainter *painter, int x0, int y0, int c, uint32_t color) {
#ifdef UI_FREETYPE
	UIFont *font = ui.activeFont;

	if (font->isFreeType) {
		if (c < 0 || c > 127) c = '?';
		if (c == '\r') c = ' ';

		if (!font->glyphsRendered[c]) {
			FT_Load_Char(font->font, c == 24 ? 0x2191 : c == 25 ? 0x2193 : c == 26 ? 0x2192 : c == 27 ? 0x2190 : c, FT_LOAD_DEFAULT);
#ifdef UI_FREETYPE_SUBPIXEL
			FT_Render_Glyph(font->font->glyph, FT_RENDER_MODE_LCD);
#else
			FT_Render_Glyph(font->font->glyph, FT_RENDER_MODE_NORMAL);
#endif
			FT_Bitmap_Copy(ui.ft, &font->font->glyph->bitmap, &font->glyphs[c]);
			font->glyphOffsetsX[c] = font->font->glyph->bitmap_left;
			font->glyphOffsetsY[c] = font->font->size->metrics.ascender / 64 - font->font->glyph->bitmap_top;
			font->glyphsRendered[c] = true;
		}

		FT_Bitmap *bitmap = &font->glyphs[c];
		x0 += font->glyphOffsetsX[c], y0 += font->glyphOffsetsY[c];

		for (int y = 0; y < (int) bitmap->rows; y++) {
			if (y0 + y < painter->clip.t) continue;
			if (y0 + y >= painter->clip.b) break;

			int width = bitmap->width;
#ifdef UI_FREETYPE_SUBPIXEL
			width /= 3;
#endif

			for (int x = 0; x < width; x++) {
				if (x0 + x < painter->clip.l) continue;
				if (x0 + x >= painter->clip.r) break;

				uint32_t *destination = painter->bits + (x0 + x) + (y0 + y) * painter->width;
				uint32_t original = *destination;

#ifdef UI_FREETYPE_SUBPIXEL
				uint32_t ra = ((uint8_t *) bitmap->buffer)[x * 3 + y * bitmap->pitch + 0];
				uint32_t ga = ((uint8_t *) bitmap->buffer)[x * 3 + y * bitmap->pitch + 1];
				uint32_t ba = ((uint8_t *) bitmap->buffer)[x * 3 + y * bitmap->pitch + 2];
				ra += (ga - ra) / 2, ba += (ga - ba) / 2;
#else
				uint32_t ra = ((uint8_t *) bitmap->buffer)[x + y * bitmap->pitch];
				uint32_t ga = ra, ba = ra;
#endif
				uint32_t r2 = (255 - ra) * ((original & 0x000000FF) >> 0);
				uint32_t g2 = (255 - ga) * ((original & 0x0000FF00) >> 8);
				uint32_t b2 = (255 - ba) * ((original & 0x00FF0000) >> 16);
				uint32_t r1 = ra * ((color & 0x000000FF) >> 0);
				uint32_t g1 = ga * ((color & 0x0000FF00) >> 8);
				uint32_t b1 = ba * ((color & 0x00FF0000) >> 16);

				uint32_t result = 0xFF000000 | (0x00FF0000 & ((b1 + b2) << 8)) 
					| (0x0000FF00 & ((g1 + g2) << 0)) 
					| (0x000000FF & ((r1 + r2) >> 8));
				*destination = result;
			}
		}

		return;
	}
#endif

	if (c < 0 || c > 127) c = '?';

	UIRectangle rectangle = UIRectangleIntersection(painter->clip, UI_RECT_4(x0, x0 + 8, y0, y0 + 16));

	const uint8_t *data = (const uint8_t *) _uiFont + c * 16;

	for (int i = rectangle.t; i < rectangle.b; i++) {
		uint32_t *bits = painter->bits + i * painter->width + rectangle.l;
		uint8_t byte = data[i - y0];

		for (int j = rectangle.l; j < rectangle.r; j++) {
			if (byte & (1 << (j - x0))) {
				*bits = color;
			}

			bits++;
		}
	}
}

ptrdiff_t _UIStringLength(const char *cString) {
	if (!cString) return 0;
	ptrdiff_t length;
	for (length = 0; cString[length]; length++);
	return length;
}

char *UIStringCopy(const char *in, ptrdiff_t inBytes) {
	if (inBytes == -1) {
		inBytes = _UIStringLength(in);
	}

	char *buffer = (char *) UI_MALLOC(inBytes + 1);
	
	for (intptr_t i = 0; i < inBytes; i++) {
		buffer[i] = in[i];
	}
	
	buffer[inBytes] = 0;
	return buffer;
}

int UIMeasureStringWidth(const char *string, ptrdiff_t bytes) {
	if (bytes == -1) {
		bytes = _UIStringLength(string);
	}
	
	return bytes * ui.activeFont->glyphWidth;
}

int UIMeasureStringHeight() {
	return ui.activeFont->glyphHeight;
}

void UIDrawString(UIPainter *painter, UIRectangle r, const char *string, ptrdiff_t bytes, uint32_t color, int align, UIStringSelection *selection) {
	UIRectangle oldClip = painter->clip;
	painter->clip = UIRectangleIntersection(r, oldClip);

	if (!UI_RECT_VALID(painter->clip)) {
		painter->clip = oldClip;
		return;
	}

	if (bytes == -1) {
		bytes = _UIStringLength(string);
	}

	int width = UIMeasureStringWidth(string, bytes);
	int height = UIMeasureStringHeight();
	int x = align == UI_ALIGN_CENTER ? ((r.l + r.r - width) / 2) : align == UI_ALIGN_RIGHT ? (r.r - width) : r.l;
	int y = (r.t + r.b - height) / 2;
	int i = 0, j = 0;

	int selectFrom = -1, selectTo = -1;

	if (selection) {
		selectFrom = selection->carets[0];
		selectTo = selection->carets[1];
		
		if (selectFrom > selectTo) {
			UI_SWAP(int, selectFrom, selectTo);
		}
	}

	for (; j < bytes; j++) {
		char c = *string++;
		uint32_t colorText = color;

		if (j >= selectFrom && j < selectTo) {
			UIDrawBlock(painter, UI_RECT_4(x, x + ui.activeFont->glyphWidth, y, y + height), selection->colorBackground);
			colorText = selection->colorText;
		}

		if (c != '\t') {
			UIDrawGlyph(painter, x, y, c, colorText);
		}

		if (selection && selection->carets[0] == j) {
			UIDrawInvert(painter, UI_RECT_4(x, x + 1, y, y + height));
		}

		x += ui.activeFont->glyphWidth, i++;

		if (c == '\t') {
			while (i & 3) x += ui.activeFont->glyphWidth, i++;
		}
	}

	if (selection && selection->carets[0] == j) {
		UIDrawInvert(painter, UI_RECT_4(x, x + 1, y, y + height));
	}

	painter->clip = oldClip;
}

void UIDrawBorder(UIPainter *painter, UIRectangle r, uint32_t borderColor, UIRectangle borderSize) {
	UIDrawBlock(painter, UI_RECT_4(r.l, r.r, r.t, r.t + borderSize.t), borderColor);
	UIDrawBlock(painter, UI_RECT_4(r.l, r.l + borderSize.l, r.t + borderSize.t, r.b - borderSize.b), borderColor);
	UIDrawBlock(painter, UI_RECT_4(r.r - borderSize.r, r.r, r.t + borderSize.t, r.b - borderSize.b), borderColor);
	UIDrawBlock(painter, UI_RECT_4(r.l, r.r, r.b - borderSize.b, r.b), borderColor);
}

void UIDrawRectangle(UIPainter *painter, UIRectangle r, uint32_t mainColor, uint32_t borderColor, UIRectangle borderSize) {
	UIDrawBorder(painter, r, borderColor, borderSize);
	UIDrawBlock(painter, UI_RECT_4(r.l + borderSize.l, r.r - borderSize.r, r.t + borderSize.t, r.b - borderSize.b), mainColor);
}

void UIElementMove(UIElement *element, UIRectangle bounds, bool alwaysLayout) {
	UIRectangle oldClip = element->clip;
	element->clip = UIRectangleIntersection(element->parent->clip, bounds);

	if (!UIRectangleEquals(element->bounds, bounds) || !UIRectangleEquals(element->clip, oldClip) || alwaysLayout) {
		element->bounds = bounds;
		UIElementMessage(element, UI_MSG_LAYOUT, 0, 0);
	}
}

int UIElementMessage(UIElement *element, UIMessage message, int di, void *dp) {
	if (message != UI_MSG_DESTROY && (element->flags & UI_ELEMENT_DESTROY)) {
		return 0;
	}

	if (message >= UI_MSG_INPUT_EVENTS_START && message <= UI_MSG_INPUT_EVENTS_END && (element->flags & UI_ELEMENT_DISABLED)) {
		return 0;
	}

	if (element->messageUser) {
		int result = element->messageUser(element, message, di, dp);

		if (result) {
			return result;
		}
	}

	if (element->messageClass) {
		return element->messageClass(element, message, di, dp);
	} else {
		return 0;
	}
}

void UIElementChangeParent(UIElement *element, UIElement *newParent, UIElement *insertBefore) {
	UIElement **link = &element->parent->children;

	while (true) {
		if (*link == element) {
			*link = element->next;
			break;
		} else {
			link = &(*link)->next;
		}
	}

	link = &newParent->children;
	element->next = insertBefore;

	while (true) {
		if ((*link) == insertBefore) {
			*link = element;
			break;
		} else {
			link = &(*link)->next;
		}
	}

	element->parent = newParent;
	element->window = newParent->window;
}

UIElement *UIElementCreate(size_t bytes, UIElement *parent, uint32_t flags, int (*message)(UIElement *, UIMessage, int, void *), const char *cClassName) {
	UI_ASSERT(bytes >= sizeof(UIElement));
	UIElement *element = (UIElement *) UI_CALLOC(bytes);
	element->flags = flags;
	element->messageClass = message;

	if (!parent && (~flags & UI_ELEMENT_WINDOW)) {
		UI_ASSERT(ui.parentStackCount);
		parent = ui.parentStack[ui.parentStackCount - 1];
	}

	if ((~flags & UI_ELEMENT_NON_CLIENT) && parent) {
		UIElementMessage(parent, UI_MSG_CLIENT_PARENT, 0, &parent);
	}

	if (parent) {
		element->window = parent->window;
		element->parent = parent;

		if (parent->children) {
			UIElement *sibling = parent->children;

			while (sibling->next) {
				sibling = sibling->next;
			}

			sibling->next = element;
		} else {
			parent->children = element;
		}

		UI_ASSERT(~parent->flags & UI_ELEMENT_DESTROY);
	}

#ifdef UI_DEBUG
	element->cClassName = cClassName;
	static int id = 0;
	element->id = ++id;
	_UIInspectorRefresh();
#endif

	if (flags & UI_ELEMENT_PARENT_PUSH) {
		UIParentPush(element);
	}

	return element;
}

UIElement *UIParentPush(UIElement *element) {
	UI_ASSERT(ui.parentStackCount != sizeof(ui.parentStack) / sizeof(ui.parentStack[0]));
	ui.parentStack[ui.parentStackCount++] = element;
	return element;
}

UIElement *UIParentPop() {
	UI_ASSERT(ui.parentStackCount);
	ui.parentStackCount--;
	return ui.parentStack[ui.parentStackCount];
}

int _UIPanelMeasure(UIPanel *panel) {
	bool horizontal = panel->e.flags & UI_PANEL_HORIZONTAL;
	int size = 0;
	UIElement *child = panel->e.children;

	while (child) {
		if (~child->flags & UI_ELEMENT_HIDE) {
			if (horizontal) {
				int height = UIElementMessage(child, UI_MSG_GET_HEIGHT, 0, 0);

				if (height > size) {
					size = height;
				}
			} else {
				int width = UIElementMessage(child, UI_MSG_GET_WIDTH, 0, 0);

				if (width > size) {
					size = width;
				}
			}
		}

		child = child->next;
	}

	int border = 0;

	if (horizontal) {
		border = panel->border.t + panel->border.b;
	} else {
		border = panel->border.l + panel->border.r;
	}

	return size + border * panel->e.window->scale;
}

int _UIPanelLayout(UIPanel *panel, UIRectangle bounds, bool measure) {
	bool horizontal = panel->e.flags & UI_PANEL_HORIZONTAL;
	float scale = panel->e.window->scale;
	int position = (horizontal ? panel->border.l : panel->border.t) * scale;
	if (panel->scrollBar && !measure) position -= panel->scrollBar->position;
	int hSpace = UI_RECT_WIDTH(bounds) - UI_RECT_TOTAL_H(panel->border) * scale;
	int vSpace = UI_RECT_HEIGHT(bounds) - UI_RECT_TOTAL_V(panel->border) * scale;

	int available = horizontal ? hSpace : vSpace;
	int fill = 0, count = 0, perFill = 0;

	for (UIElement *child = panel->e.children; child; child = child->next) {
		if (child->flags & (UI_ELEMENT_HIDE | UI_ELEMENT_NON_CLIENT)) {
			continue;
		}

		count++;

		if (horizontal) {
			if (child->flags & UI_ELEMENT_H_FILL) {
				fill++;
			} else if (available > 0) {
				available -= UIElementMessage(child, UI_MSG_GET_WIDTH, vSpace, 0);
			}
		} else {
			if (child->flags & UI_ELEMENT_V_FILL) {
				fill++;
			} else if (available > 0) {
				available -= UIElementMessage(child, UI_MSG_GET_HEIGHT, hSpace, 0);
			}
		}
	}

	if (count) {
		available -= (count - 1) * (int) (panel->gap * scale);
	}

	if (available > 0 && fill) {
		perFill = available / fill;
	}

	bool expand = panel->e.flags & UI_PANEL_EXPAND;
	int scaledBorder2 = (horizontal ? panel->border.t : panel->border.l) * panel->e.window->scale;

	for (UIElement *child = panel->e.children; child; child = child->next) {
		if (child->flags & (UI_ELEMENT_HIDE | UI_ELEMENT_NON_CLIENT)) {
			continue;
		}

		if (horizontal) {
			int height = ((child->flags & UI_ELEMENT_V_FILL) || expand) ? vSpace : UIElementMessage(child, UI_MSG_GET_HEIGHT, 0, 0);
			int width = (child->flags & UI_ELEMENT_H_FILL) ? perFill : UIElementMessage(child, UI_MSG_GET_WIDTH, height, 0);
			UIRectangle relative = UI_RECT_4(position, position + width, 
					scaledBorder2 + (vSpace - height) / 2, 
					scaledBorder2 + (vSpace + height) / 2);
			if (!measure) UIElementMove(child, UIRectangleTranslate(relative, bounds), false);
			position += width + panel->gap * scale;
		} else {
			int width = ((child->flags & UI_ELEMENT_H_FILL) || expand) ? hSpace : UIElementMessage(child, UI_MSG_GET_WIDTH, 0, 0);
			int height = (child->flags & UI_ELEMENT_V_FILL) ? perFill : UIElementMessage(child, UI_MSG_GET_HEIGHT, width, 0);
			UIRectangle relative = UI_RECT_4(scaledBorder2 + (hSpace - width) / 2, 
					scaledBorder2 + (hSpace + width) / 2, position, position + height);
			if (!measure) UIElementMove(child, UIRectangleTranslate(relative, bounds), false);
			position += height + panel->gap * scale;
		}
	}

	return position - panel->gap * scale + (horizontal ? panel->border.r : panel->border.b) * scale;
}

int _UIPanelMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UIPanel *panel = (UIPanel *) element;
	bool horizontal = element->flags & UI_PANEL_HORIZONTAL;

	if (message == UI_MSG_LAYOUT) {
		int scrollBarWidth = panel->scrollBar ? (UI_SIZE_SCROLL_BAR * element->window->scale) : 0;
		UIRectangle bounds = element->bounds;
		bounds.r -= scrollBarWidth;

		if (panel->scrollBar) {
			UIRectangle scrollBarBounds = element->bounds;
			scrollBarBounds.l = scrollBarBounds.r - scrollBarWidth;
			panel->scrollBar->maximum = _UIPanelLayout(panel, bounds, true);
			panel->scrollBar->page = UI_RECT_HEIGHT(element->bounds);
			UIElementMove(&panel->scrollBar->e, scrollBarBounds, true);
		}

		_UIPanelLayout(panel, bounds, false);
	} else if (message == UI_MSG_GET_WIDTH) {
		if (horizontal) {
			return _UIPanelLayout(panel, UI_RECT_4(0, 0, 0, di), true);
		} else {
			return _UIPanelMeasure(panel);
		}
	} else if (message == UI_MSG_GET_HEIGHT) {
		if (horizontal) {
			return _UIPanelMeasure(panel);
		} else {
			int width = di && panel->scrollBar ? (di - UI_SIZE_SCROLL_BAR * element->window->scale) : di;
			return _UIPanelLayout(panel, UI_RECT_4(0, width, 0, 0), true);
		}
	} else if (message == UI_MSG_PAINT) {
		if (element->flags & UI_PANEL_GRAY) {
			UIDrawBlock((UIPainter *) dp, element->bounds, ui.theme.panel1);
		} else if (element->flags & UI_PANEL_WHITE) {
			UIDrawBlock((UIPainter *) dp, element->bounds, ui.theme.panel2);
		} 
		
		if (element->flags & UI_PANEL_BORDER) {
			UIDrawBorder((UIPainter *) dp, element->bounds, ui.theme.border, UI_RECT_1((int) element->window->scale));
		}
	} else if (message == UI_MSG_MOUSE_WHEEL && panel->scrollBar) {
		return UIElementMessage(&panel->scrollBar->e, message, di, dp);
	} else if (message == UI_MSG_SCROLLED) {
		UIElementRefresh(element);
	}

	return 0;
}

UIPanel *UIPanelCreate(UIElement *parent, uint32_t flags) {
	UIPanel *panel = (UIPanel *) UIElementCreate(sizeof(UIPanel), parent, flags, _UIPanelMessage, "Panel");

	if (flags & UI_PANEL_MEDIUM_SPACING) {
		panel->border = UI_RECT_1(UI_SIZE_PANE_MEDIUM_BORDER);
		panel->gap = UI_SIZE_PANE_MEDIUM_GAP;
	} else if (flags & UI_PANEL_SMALL_SPACING) {
		panel->border = UI_RECT_1(UI_SIZE_PANE_SMALL_BORDER);
		panel->gap = UI_SIZE_PANE_SMALL_GAP;
	}

	if (flags & UI_PANEL_SCROLL) {
		panel->scrollBar = UIScrollBarCreate(&panel->e, UI_ELEMENT_NON_CLIENT);
	}

	return panel;
}

void _UIButtonCalculateColors(UIElement *element, uint32_t *color, uint32_t *textColor) {
	bool disabled = element->flags & UI_ELEMENT_DISABLED;
	bool focused = element == element->window->focused;
	bool pressed = element == element->window->pressed;
	bool hovered = element == element->window->hovered;
	*color = disabled ? ui.theme.buttonDisabled
		: (pressed && hovered) ? ui.theme.buttonPressed 
		: (pressed || hovered) ? ui.theme.buttonHovered 
		: focused ? ui.theme.selected : ui.theme.buttonNormal;
	*textColor = disabled ? ui.theme.textDisabled 
		: *color == ui.theme.selected ? ui.theme.textSelected : ui.theme.text;
}


int _UIButtonMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UIButton *button = (UIButton *) element;
	bool isMenuItem = element->flags & UI_BUTTON_MENU_ITEM;
	bool isDropDown = element->flags & UI_BUTTON_DROP_DOWN;
	
	if (message == UI_MSG_GET_HEIGHT) {
		if (isMenuItem) {
			return UI_SIZE_MENU_ITEM_HEIGHT * element->window->scale;
		} else {
			return UI_SIZE_BUTTON_HEIGHT * element->window->scale;
		}
	} else if (message == UI_MSG_GET_WIDTH) {
		int labelSize = UIMeasureStringWidth(button->label, button->labelBytes);
		int paddedSize = labelSize + UI_SIZE_BUTTON_PADDING * element->window->scale;
		if (isDropDown) paddedSize += ui.activeFont->glyphWidth * 2;
		int minimumSize = ((element->flags & UI_BUTTON_SMALL) ? 0 
				: isMenuItem ? UI_SIZE_MENU_ITEM_MINIMUM_WIDTH 
				: UI_SIZE_BUTTON_MINIMUM_WIDTH) 
			* element->window->scale;
		return paddedSize > minimumSize ? paddedSize : minimumSize;
	} else if (message == UI_MSG_PAINT) {
		UIPainter *painter = (UIPainter *) dp;

		uint32_t color, textColor;
		_UIButtonCalculateColors(element, &color, &textColor);

		UIDrawRectangle(painter, element->bounds, color, ui.theme.border, UI_RECT_1(isMenuItem ? 0 : 1));

		if (element->flags & UI_BUTTON_CHECKED) {
			UIDrawBlock(painter, UIRectangleAdd(element->bounds, 
				UI_RECT_1I((int) (UI_SIZE_BUTTON_CHECKED_AREA * element->window->scale))), ui.theme.buttonPressed);
		}

		UIRectangle bounds = UIRectangleAdd(element->bounds, UI_RECT_2I((int) (UI_SIZE_MENU_ITEM_MARGIN * element->window->scale), 0));

		if (isMenuItem) {
			if (button->labelBytes == -1) {
				button->labelBytes = _UIStringLength(button->label);
			}

			int tab = 0;
			for (; tab < button->labelBytes && button->label[tab] != '\t'; tab++);

			UIDrawString(painter, bounds, button->label, tab, textColor, UI_ALIGN_LEFT, NULL);

			if (button->labelBytes > tab) {
				UIDrawString(painter, bounds, button->label + tab + 1, button->labelBytes - tab - 1, textColor, UI_ALIGN_RIGHT, NULL);
			}
		} else if (isDropDown) {
			UIDrawString(painter, bounds, button->label, button->labelBytes, textColor, UI_ALIGN_LEFT, NULL);
			UIDrawString(painter, bounds, "\x19", 1, textColor, UI_ALIGN_RIGHT, NULL);
		} else {
			UIDrawString(painter, element->bounds, button->label, button->labelBytes, textColor, UI_ALIGN_CENTER, NULL);
		}
	} else if (message == UI_MSG_UPDATE) {
		UIElementRepaint(element, NULL);
	} else if (message == UI_MSG_DESTROY) {
		UI_FREE(button->label);
	} else if (message == UI_MSG_LEFT_DOWN) {
		if (element->flags & UI_BUTTON_CAN_FOCUS) {
			UIElementFocus(element);
		}
	} else if (message == UI_MSG_KEY_TYPED) {
		UIKeyTyped *m = (UIKeyTyped *) dp;
		
		if (m->textBytes == 1 && m->text[0] == ' ') {
			UIElementMessage(element, UI_MSG_CLICKED, 0, 0);
			UIElementRepaint(element, NULL);
		}
	} else if (message == UI_MSG_CLICKED) {
		if (button->invoke) {
			button->invoke(element->cp);
		}
	}

	return 0;
}

UIButton *UIButtonCreate(UIElement *parent, uint32_t flags, const char *label, ptrdiff_t labelBytes) {
	UIButton *button = (UIButton *) UIElementCreate(sizeof(UIButton), parent, flags | UI_ELEMENT_TAB_STOP, _UIButtonMessage, "Button");
	button->label = UIStringCopy(label, (button->labelBytes = labelBytes));
	return button;
}

int _UICheckboxMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UICheckbox *box = (UICheckbox *) element;
	
	if (message == UI_MSG_GET_HEIGHT) {
		return UI_SIZE_BUTTON_HEIGHT * element->window->scale;
	} else if (message == UI_MSG_GET_WIDTH) {
		int labelSize = UIMeasureStringWidth(box->label, box->labelBytes);
		return (labelSize + UI_SIZE_CHECKBOX_BOX + UI_SIZE_CHECKBOX_GAP) * element->window->scale;
	} else if (message == UI_MSG_PAINT) {
		UIPainter *painter = (UIPainter *) dp;
		uint32_t color, textColor;
		_UIButtonCalculateColors(element, &color, &textColor);
		int midY = (element->bounds.t + element->bounds.b) / 2;
		UIRectangle boxBounds = UI_RECT_4(element->bounds.l, element->bounds.l + UI_SIZE_CHECKBOX_BOX, 
				midY - UI_SIZE_CHECKBOX_BOX / 2, midY + UI_SIZE_CHECKBOX_BOX / 2);
		UIDrawRectangle(painter, boxBounds, color, ui.theme.border, UI_RECT_1(1));
		UIDrawString(painter, UIRectangleAdd(boxBounds, UI_RECT_4(1, 0, 0, 0)), 
				box->check == UI_CHECK_CHECKED ? "*" : box->check == UI_CHECK_INDETERMINATE ? "-" : " ", -1, 
				textColor, UI_ALIGN_CENTER, NULL);
		UIDrawString(painter, UIRectangleAdd(element->bounds, UI_RECT_4(UI_SIZE_CHECKBOX_BOX + UI_SIZE_CHECKBOX_GAP, 0, 0, 0)), 
				box->label, box->labelBytes, textColor, UI_ALIGN_LEFT, NULL);
	} else if (message == UI_MSG_UPDATE) {
		UIElementRepaint(element, NULL);
	} else if (message == UI_MSG_DESTROY) {
		UI_FREE(box->label);
	} else if (message == UI_MSG_KEY_TYPED) {
		UIKeyTyped *m = (UIKeyTyped *) dp;
		
		if (m->textBytes == 1 && m->text[0] == ' ') {
			UIElementMessage(element, UI_MSG_CLICKED, 0, 0);
			UIElementRepaint(element, NULL);
		}
	} else if (message == UI_MSG_CLICKED) {
		box->check = (box->check + 1) % ((element->flags & UI_CHECKBOX_ALLOW_INDETERMINATE) ? 3 : 2);
		UIElementRepaint(element, NULL);
		if (box->invoke) box->invoke(element->cp);
	}

	return 0;
}

UICheckbox *UICheckboxCreate(UIElement *parent, uint32_t flags, const char *label, ptrdiff_t labelBytes) {
	UICheckbox *box = (UICheckbox *) UIElementCreate(sizeof(UICheckbox), parent, flags | UI_ELEMENT_TAB_STOP, _UICheckboxMessage, "Checkbox");
	box->label = UIStringCopy(label, (box->labelBytes = labelBytes));
	return box;
}

int _UILabelMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UILabel *label = (UILabel *) element;
	
	if (message == UI_MSG_GET_HEIGHT) {
		return UIMeasureStringHeight();
	} else if (message == UI_MSG_GET_WIDTH) {
		return UIMeasureStringWidth(label->label, label->labelBytes);
	} else if (message == UI_MSG_PAINT) {
		UIPainter *painter = (UIPainter *) dp;
		UIDrawString(painter, element->bounds, label->label, label->labelBytes, ui.theme.text, UI_ALIGN_LEFT, NULL);
	} else if (message == UI_MSG_DESTROY) {
		UI_FREE(label->label);
	}

	return 0;
}

void UILabelSetContent(UILabel *label, const char *string, ptrdiff_t stringBytes) {
	UI_FREE(label->label);
	label->label = UIStringCopy(string, (label->labelBytes = stringBytes));
}

UILabel *UILabelCreate(UIElement *parent, uint32_t flags, const char *string, ptrdiff_t stringBytes) {
	UILabel *label = (UILabel *) UIElementCreate(sizeof(UILabel), parent, flags, _UILabelMessage, "Label");
	label->label = UIStringCopy(string, (label->labelBytes = stringBytes));
	return label;
}

int _UISplitPaneMessage(UIElement *element, UIMessage message, int di, void *dp);

int _UISplitterMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UISplitPane *splitPane = (UISplitPane *) element->parent;
	bool vertical = splitPane->e.flags & UI_SPLIT_PANE_VERTICAL;

	if (message == UI_MSG_PAINT) {
		UIRectangle borders = vertical ? UI_RECT_2(0, 1) : UI_RECT_2(1, 0);
		UIDrawRectangle((UIPainter *) dp, element->bounds, ui.theme.buttonNormal, ui.theme.border, borders);
	} else if (message == UI_MSG_GET_CURSOR) {
		return vertical ? UI_CURSOR_SPLIT_V : UI_CURSOR_SPLIT_H;
	} else if (message == UI_MSG_MOUSE_DRAG) {
		int cursor = vertical ? element->window->cursorY : element->window->cursorX;
		int splitterSize = UI_SIZE_SPLITTER * element->window->scale;
		int space = (vertical ? UI_RECT_HEIGHT(splitPane->e.bounds) : UI_RECT_WIDTH(splitPane->e.bounds)) - splitterSize;
		float oldWeight = splitPane->weight;
		splitPane->weight = (float) (cursor - splitterSize / 2 - (vertical ? splitPane->e.bounds.t : splitPane->e.bounds.l)) / space;
		if (splitPane->weight < 0.05f) splitPane->weight = 0.05f;
		if (splitPane->weight > 0.95f) splitPane->weight = 0.95f;

		if (element->next->next->messageClass == _UISplitPaneMessage 
				&& (element->next->next->flags & UI_SPLIT_PANE_VERTICAL) == (splitPane->e.flags & UI_SPLIT_PANE_VERTICAL)) {
			UISplitPane *subSplitPane = (UISplitPane *) element->next->next;
			subSplitPane->weight = (splitPane->weight - oldWeight - subSplitPane->weight + oldWeight * subSplitPane->weight) / (-1 + splitPane->weight);
			if (subSplitPane->weight < 0.05f) subSplitPane->weight = 0.05f;
			if (subSplitPane->weight > 0.95f) subSplitPane->weight = 0.95f;
		}

		UIElementRefresh(&splitPane->e);
	}

	return 0;
}

int _UISplitPaneMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UISplitPane *splitPane = (UISplitPane *) element;
	bool vertical = splitPane->e.flags & UI_SPLIT_PANE_VERTICAL;

	if (message == UI_MSG_LAYOUT) {
		UIElement *splitter = element->children;
		UI_ASSERT(splitter);
		UIElement *left = splitter->next;
		UI_ASSERT(left);
		UIElement *right = left->next;
		UI_ASSERT(right);
		UI_ASSERT(!right->next);

		int splitterSize = UI_SIZE_SPLITTER * element->window->scale;
		int space = (vertical ? UI_RECT_HEIGHT(element->bounds) : UI_RECT_WIDTH(element->bounds)) - splitterSize;
		int leftSize = space * splitPane->weight;
		int rightSize = space - leftSize;

		if (vertical) {
			UIElementMove(left, UI_RECT_4(element->bounds.l, element->bounds.r, element->bounds.t, element->bounds.t + leftSize), false);
			UIElementMove(splitter, UI_RECT_4(element->bounds.l, element->bounds.r, element->bounds.t + leftSize, element->bounds.t + leftSize + splitterSize), false);
			UIElementMove(right, UI_RECT_4(element->bounds.l, element->bounds.r, element->bounds.b - rightSize, element->bounds.b), false);
		} else {
			UIElementMove(left, UI_RECT_4(element->bounds.l, element->bounds.l + leftSize, element->bounds.t, element->bounds.b), false);
			UIElementMove(splitter, UI_RECT_4(element->bounds.l + leftSize, element->bounds.l + leftSize + splitterSize, element->bounds.t, element->bounds.b), false);
			UIElementMove(right, UI_RECT_4(element->bounds.r - rightSize, element->bounds.r, element->bounds.t, element->bounds.b), false);
		}
	}

	return 0;
}

UISplitPane *UISplitPaneCreate(UIElement *parent, uint32_t flags, float weight) {
	UISplitPane *splitPane = (UISplitPane *) UIElementCreate(sizeof(UISplitPane), parent, flags, _UISplitPaneMessage, "Split Pane");
	splitPane->weight = weight;
	UIElementCreate(sizeof(UIElement), &splitPane->e, 0, _UISplitterMessage, "Splitter");
	return splitPane;
}

int _UITabPaneMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UITabPane *tabPane = (UITabPane *) element;
	
	if (message == UI_MSG_PAINT) {
		UIPainter *painter = (UIPainter *) dp;
		UIRectangle top = element->bounds;
		top.b = top.t + UI_SIZE_BUTTON_HEIGHT * element->window->scale;
		UIDrawRectangle(painter, top, ui.theme.panel1, ui.theme.border, UI_RECT_4(0, 0, 0, 1));

		UIRectangle tab = top;
		tab.l += UI_SIZE_TAB_PANE_SPACE_LEFT * element->window->scale;
		tab.t += UI_SIZE_TAB_PANE_SPACE_TOP * element->window->scale;

		int position = 0;
		int index = 0;

		while (true) {
			int end = position;
			for (; tabPane->tabs[end] != '\t' && tabPane->tabs[end]; end++);

			int width = UIMeasureStringWidth(tabPane->tabs, end - position);
			tab.r = tab.l + width + UI_SIZE_BUTTON_PADDING;

			uint32_t color = tabPane->active == index ? ui.theme.buttonPressed : ui.theme.buttonNormal;

			UIRectangle t = tab;

			if (tabPane->active == index) {
				t.b++;
				t.t--;
			} else {
				t.t++;
			}

			UIDrawRectangle(painter, t, color, ui.theme.border, UI_RECT_1(1));
			UIDrawString(painter, tab, tabPane->tabs + position, end - position, ui.theme.text, UI_ALIGN_CENTER, NULL);
			tab.l = tab.r - 1;

			if (tabPane->tabs[end] == '\t') {
				position = end + 1;
				index++;
			} else {
				break;
			}
		}
	} else if (message == UI_MSG_LEFT_DOWN) {
		UIRectangle tab = element->bounds;
		tab.b = tab.t + UI_SIZE_BUTTON_HEIGHT * element->window->scale;
		tab.l += UI_SIZE_TAB_PANE_SPACE_LEFT * element->window->scale;
		tab.t += UI_SIZE_TAB_PANE_SPACE_TOP * element->window->scale;

		int position = 0;
		int index = 0;

		while (true) {
			int end = position;
			for (; tabPane->tabs[end] != '\t' && tabPane->tabs[end]; end++);

			int width = UIMeasureStringWidth(tabPane->tabs, end - position);
			tab.r = tab.l + width + UI_SIZE_BUTTON_PADDING;

			if (UIRectangleContains(tab, element->window->cursorX, element->window->cursorY)) {
				tabPane->active = index;
				UIElementMessage(element, UI_MSG_LAYOUT, 0, 0);
				UIElementRepaint(element, NULL);
				break;
			}

			tab.l = tab.r - 1;

			if (tabPane->tabs[end] == '\t') {
				position = end + 1;
				index++;
			} else {
				break;
			}
		}
	} else if (message == UI_MSG_LAYOUT) {
		UIElement *child = element->children;
		int index = 0;

		UIRectangle content = element->bounds;
		content.t += UI_SIZE_BUTTON_HEIGHT * element->window->scale;

		while (child) {
			if (tabPane->active == index) {
				child->flags &= ~UI_ELEMENT_HIDE;
				UIElementMove(child, content, false);
				UIElementMessage(child, UI_MSG_TAB_SELECTED, 0, 0);
			} else {
				child->flags |= UI_ELEMENT_HIDE;
			}

			child = child->next;
			index++;
		}
	} else if (message == UI_MSG_GET_HEIGHT) {
		UIElement *child = element->children;
		int index = 0;
		int baseHeight = UI_SIZE_BUTTON_HEIGHT * element->window->scale;

		while (child) {
			if (tabPane->active == index) {
				return baseHeight + UIElementMessage(child, UI_MSG_GET_HEIGHT, di, dp);
			}

			child = child->next;
			index++;
		}
	} else if (message == UI_MSG_DESTROY) {
		UI_FREE(tabPane->tabs);
	}

	return 0;
}

UITabPane *UITabPaneCreate(UIElement *parent, uint32_t flags, const char *tabs) {
	UITabPane *tabPane = (UITabPane *) UIElementCreate(sizeof(UITabPane), parent, flags, _UITabPaneMessage, "Tab Pane");
	tabPane->tabs = UIStringCopy(tabs, -1);
	return tabPane;
}

int _UISpacerMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UISpacer *spacer = (UISpacer *) element;
	
	if (message == UI_MSG_GET_HEIGHT) {
		return spacer->height * element->window->scale;
	} else if (message == UI_MSG_GET_WIDTH) {
		return spacer->width * element->window->scale;
	} else if (message == UI_MSG_PAINT && (element->flags & UI_SPACER_LINE)) {
		UIDrawBlock((UIPainter *) dp, element->bounds, ui.theme.border);
	}

	return 0;
}

UISpacer *UISpacerCreate(UIElement *parent, uint32_t flags, int width, int height) {
	UISpacer *spacer = (UISpacer *) UIElementCreate(sizeof(UISpacer), parent, flags, _UISpacerMessage, "Spacer");
	spacer->width = width;
	spacer->height = height;
	return spacer;
}

int _UIScrollBarMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UIScrollBar *scrollBar = (UIScrollBar *) element;

	if (message == UI_MSG_GET_WIDTH || message == UI_MSG_GET_HEIGHT) {
		return UI_SIZE_SCROLL_BAR * element->window->scale;
	} else if (message == UI_MSG_LAYOUT) {
		UIElement *up = element->children;
		UIElement *thumb = up->next;
		UIElement *down = thumb->next;

		if (scrollBar->page >= scrollBar->maximum || scrollBar->maximum <= 0 || scrollBar->page <= 0) {
			up->flags |= UI_ELEMENT_HIDE;
			thumb->flags |= UI_ELEMENT_HIDE;
			down->flags |= UI_ELEMENT_HIDE;

			scrollBar->position = 0;
		} else {
			up->flags &= ~UI_ELEMENT_HIDE;
			thumb->flags &= ~UI_ELEMENT_HIDE;
			down->flags &= ~UI_ELEMENT_HIDE;

			int size = scrollBar->horizontal ? UI_RECT_WIDTH(element->bounds) : UI_RECT_HEIGHT(element->bounds);
			int thumbSize = size * scrollBar->page / scrollBar->maximum;

			if (thumbSize < UI_SIZE_SCROLL_MINIMUM_THUMB * element->window->scale) {
				thumbSize = UI_SIZE_SCROLL_MINIMUM_THUMB * element->window->scale;
			}

			if (scrollBar->position < 0) {
				scrollBar->position = 0;
			} else if (scrollBar->position > scrollBar->maximum - scrollBar->page) {
				scrollBar->position = scrollBar->maximum - scrollBar->page;
			}

			int thumbPosition = scrollBar->position / (scrollBar->maximum - scrollBar->page) * (size - thumbSize);

			if (scrollBar->position == scrollBar->maximum - scrollBar->page) {
				thumbPosition = size - thumbSize;
			}

			if (scrollBar->horizontal) {
				UIRectangle r = element->bounds;
				r.r = r.l + thumbPosition;
				UIElementMove(up, r, false);
				r.l = r.r, r.r = r.l + thumbSize;
				UIElementMove(thumb, r, false);
				r.l = r.r, r.r = element->bounds.r;
				UIElementMove(down, r, false);
			} else {
				UIRectangle r = element->bounds;
				r.b = r.t + thumbPosition;
				UIElementMove(up, r, false);
				r.t = r.b, r.b = r.t + thumbSize;
				UIElementMove(thumb, r, false);
				r.t = r.b, r.b = element->bounds.b;
				UIElementMove(down, r, false);
			}
		}
	} else if (message == UI_MSG_PAINT) {
		if (scrollBar->page >= scrollBar->maximum || scrollBar->maximum <= 0 || scrollBar->page <= 0) {
			UIDrawBlock((UIPainter *) dp, element->bounds, ui.theme.panel1);
		}
	} else if (message == UI_MSG_MOUSE_WHEEL) {
		scrollBar->position += di;
		UIElementRefresh(element);
		UIElementMessage(element->parent, UI_MSG_SCROLLED, 0, 0);
		return 1;
	}

	return 0;
}

int _UIScrollUpDownMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UIScrollBar *scrollBar = (UIScrollBar *) element->parent;
	bool isDown = element->cp;

	if (message == UI_MSG_PAINT) {
		UIPainter *painter = (UIPainter *) dp;
		uint32_t color = element == element->window->pressed ? ui.theme.buttonPressed 
			: element == element->window->hovered ? ui.theme.buttonHovered : ui.theme.panel2;
		UIDrawRectangle(painter, element->bounds, color, ui.theme.border, UI_RECT_1(0));
		
		if (scrollBar->horizontal) {
			UIDrawGlyph(painter, isDown ? (element->bounds.r - ui.activeFont->glyphWidth - 2 * element->window->scale) 
					: (element->bounds.l + 2 * element->window->scale), 
				(element->bounds.t + element->bounds.b - ui.activeFont->glyphHeight) / 2,
				isDown ? 26 : 27, ui.theme.text);
		} else {
			UIDrawGlyph(painter, (element->bounds.l + element->bounds.r - ui.activeFont->glyphWidth) / 2 + 1, 
				isDown ? (element->bounds.b - ui.activeFont->glyphHeight - 2 * element->window->scale) 
					: (element->bounds.t + 2 * element->window->scale), 
				isDown ? 25 : 24, ui.theme.text);
		}
	} else if (message == UI_MSG_UPDATE) {
		UIElementRepaint(element, NULL);
	} else if (message == UI_MSG_LEFT_DOWN) {
		UIElementAnimate(element, false);
		scrollBar->lastAnimateTime = UI_CLOCK();
	} else if (message == UI_MSG_LEFT_UP) {
		UIElementAnimate(element, true);
	} else if (message == UI_MSG_ANIMATE) {
		UI_CLOCK_T previous = scrollBar->lastAnimateTime;
		UI_CLOCK_T current = UI_CLOCK();
		UI_CLOCK_T delta = current - previous;
		double deltaSeconds = (double) delta / UI_CLOCKS_PER_SECOND;
		if (deltaSeconds > 0.1) deltaSeconds = 0.1;
		double deltaPixels = deltaSeconds * scrollBar->page * 3;
		scrollBar->lastAnimateTime = current;
		if (isDown) scrollBar->position += deltaPixels;
		else scrollBar->position -= deltaPixels;
		UIElementRefresh(&scrollBar->e);
		UIElementMessage(scrollBar->e.parent, UI_MSG_SCROLLED, 0, 0);
	}

	return 0;
}

int _UIScrollThumbMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UIScrollBar *scrollBar = (UIScrollBar *) element->parent;

	if (message == UI_MSG_PAINT) {
		UIPainter *painter = (UIPainter *) dp;
		uint32_t color = element == element->window->pressed ? ui.theme.buttonPressed 
			: element == element->window->hovered ? ui.theme.buttonHovered : ui.theme.buttonNormal;
		UIDrawRectangle(painter, element->bounds, color, ui.theme.border, UI_RECT_1(2));
	} else if (message == UI_MSG_UPDATE) {
		UIElementRepaint(element, NULL);
	} else if (message == UI_MSG_MOUSE_DRAG && element->window->pressedButton == 1) {
		if (!scrollBar->inDrag) {
			scrollBar->inDrag = true;
			
			if (scrollBar->horizontal) {
				scrollBar->dragOffset = element->bounds.l - scrollBar->e.bounds.l - element->window->cursorX;
			} else {
				scrollBar->dragOffset = element->bounds.t - scrollBar->e.bounds.t - element->window->cursorY;
			}
		}

		int thumbPosition = (scrollBar->horizontal ? element->window->cursorX : element->window->cursorY) + scrollBar->dragOffset;
		int size = scrollBar->horizontal ? (UI_RECT_WIDTH(scrollBar->e.bounds) - UI_RECT_WIDTH(element->bounds))
				: (UI_RECT_HEIGHT(scrollBar->e.bounds) - UI_RECT_HEIGHT(element->bounds));
		scrollBar->position = (double) thumbPosition / size * (scrollBar->maximum - scrollBar->page);
		UIElementRefresh(&scrollBar->e);
		UIElementMessage(scrollBar->e.parent, UI_MSG_SCROLLED, 0, 0);
	} else if (message == UI_MSG_LEFT_UP) {
		scrollBar->inDrag = false;
	}

	return 0;
}

UIScrollBar *UIScrollBarCreate(UIElement *parent, uint32_t flags) {
	UIScrollBar *scrollBar = (UIScrollBar *) UIElementCreate(sizeof(UIScrollBar), parent, flags, _UIScrollBarMessage, "Scroll Bar");
	bool horizontal = scrollBar->horizontal = flags & UI_SCROLL_BAR_HORIZONTAL;
	UIElementCreate(sizeof(UIElement), &scrollBar->e, flags, _UIScrollUpDownMessage, !horizontal ? "Scroll Up" : "Scroll Left")->cp = (void *) (uintptr_t) 0;
	UIElementCreate(sizeof(UIElement), &scrollBar->e, flags, _UIScrollThumbMessage, "Scroll Thumb");
	UIElementCreate(sizeof(UIElement), &scrollBar->e, flags, _UIScrollUpDownMessage, !horizontal ? "Scroll Down" : "Scroll Right")->cp = (void *) (uintptr_t) 1;
	return scrollBar;
}

bool _UICharIsAlpha(char c) {
	return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
}

bool _UICharIsDigit(char c) {
	return c >= '0' && c <= '9';
}

bool _UICharIsAlphaOrDigitOrUnderscore(char c) {
	return _UICharIsAlpha(c) || _UICharIsDigit(c) || c == '_';
}

int UICodeHitTest(UICode *code, int x, int y) {
	x -= code->e.bounds.l;

	if (x < 0 || x >= UI_RECT_WIDTH(code->e.bounds) - UI_SIZE_SCROLL_BAR * code->e.window->scale) {
		return 0;
	}

	y -= code->e.bounds.t - code->vScroll->position;

	UIFont *previousFont = UIFontActivate(code->font);
	int lineHeight = UIMeasureStringHeight();
	UIFontActivate(previousFont);

	if (y < 0 || y >= lineHeight * code->lineCount) {
		return 0;
	}

	int line = y / lineHeight + 1;

	if (x < UI_SIZE_CODE_MARGIN && (~code->e.flags & UI_CODE_NO_MARGIN)) {
		return -line;
	} else {
		return line;
	}
}

int UIDrawStringHighlighted(UIPainter *painter, UIRectangle lineBounds, const char *string, ptrdiff_t bytes, int tabSize) {
	if (bytes == -1) bytes = _UIStringLength(string);
	if (bytes > 10000) bytes = 10000;

	uint32_t colors[] = {
		ui.theme.codeDefault,
		ui.theme.codeComment,
		ui.theme.codeString,
		ui.theme.codeNumber,
		ui.theme.codeOperator,
		ui.theme.codePreprocessor,
	};

	int x = lineBounds.l;
	int y = (lineBounds.t + lineBounds.b - UIMeasureStringHeight()) / 2;
	int ti = 0;
	int lexState = 0;
	bool inComment = false, inIdentifier = false, inChar = false, startedString = false;
	uint32_t last = 0;

	while (bytes--) {
		char c = *string++;

		last <<= 8;
		last |= c;

		if (lexState == 4) {
			lexState = 0;
		} else if (lexState == 1) {
			if ((last & 0xFF0000) == ('*' << 16) && (last & 0xFF00) == ('/' << 8) && inComment) {
				lexState = 0, inComment = false;
			}
		} else if (lexState == 3) {
			if (!_UICharIsAlpha(c) && !_UICharIsDigit(c)) {
				lexState = 0;
			}
		} else if (lexState == 2) {
			if (!startedString) {
				if (!inChar && ((last >> 8) & 0xFF) == '"' && ((last >> 16) & 0xFF) != '\\') {
					lexState = 0;
				} else if (inChar && ((last >> 8) & 0xFF) == '\'' && ((last >> 16) & 0xFF) != '\\') {
					lexState = 0;
				}
			}

			startedString = false;
		}

		if (lexState == 0) {
			if (c == '#') {
				lexState = 5;
			} else if (c == '/' && *string == '/') {
				lexState = 1;
			} else if (c == '/' && *string == '*') {
				lexState = 1, inComment = true;
			} else if (c == '"') {
				lexState = 2;
				inChar = false;
				startedString = true;
			} else if (c == '\'') {
				lexState = 2;
				inChar = true;
				startedString = true;
			} else if (_UICharIsDigit(c) && !inIdentifier) {
				lexState = 3;
			} else if (!_UICharIsAlpha(c) && !_UICharIsDigit(c)) {
				lexState = 4;
				inIdentifier = false;
			} else {
				inIdentifier = true;
			}
		}

		if (c == '\t') {
			x += ui.activeFont->glyphWidth, ti++;
			while (ti % tabSize) x += ui.activeFont->glyphWidth, ti++;
		} else {
			UIDrawGlyph(painter, x, y, c, colors[lexState]);
			x += ui.activeFont->glyphWidth, ti++;
		}
	}

	return x;
}

int _UICodeMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UICode *code = (UICode *) element;
	
	if (message == UI_MSG_LAYOUT) {
		UIFont *previousFont = UIFontActivate(code->font);

		if (code->moveScrollToFocusNextLayout) {
			code->vScroll->position = (code->focused + 0.5) * UIMeasureStringHeight() - UI_RECT_HEIGHT(code->e.bounds) / 2;
		}

		UIRectangle scrollBarBounds = element->bounds;
		scrollBarBounds.l = scrollBarBounds.r - UI_SIZE_SCROLL_BAR * code->e.window->scale;
		code->vScroll->maximum = code->lineCount * UIMeasureStringHeight();
		code->vScroll->page = UI_RECT_HEIGHT(element->bounds);
		UIFontActivate(previousFont);
		UIElementMove(&code->vScroll->e, scrollBarBounds, true);
	} else if (message == UI_MSG_PAINT) {
		UIFont *previousFont = UIFontActivate(code->font);

		UIPainter *painter = (UIPainter *) dp;
		UIRectangle lineBounds = element->bounds;
		lineBounds.r -= UI_SIZE_SCROLL_BAR * code->e.window->scale;

		if (~code->e.flags & UI_CODE_NO_MARGIN) {
			lineBounds.l += UI_SIZE_CODE_MARGIN + UI_SIZE_CODE_MARGIN_GAP;
		}

		int lineHeight = UIMeasureStringHeight();
		lineBounds.t -= (int64_t) code->vScroll->position % lineHeight;

		UIDrawBlock(painter, element->bounds, ui.theme.codeBackground);

		for (int i = code->vScroll->position / lineHeight; i < code->lineCount; i++) {
			if (lineBounds.t > element->clip.b) {
				break;
			}

			lineBounds.b = lineBounds.t + lineHeight;

			if (~code->e.flags & UI_CODE_NO_MARGIN) {
				char string[16];
				int p = 16;
				int lineNumber = i + 1;

				while (lineNumber) {
					string[--p] = (lineNumber % 10) + '0';
					lineNumber /= 10;
				}

				UIRectangle marginBounds = lineBounds;
				marginBounds.r = marginBounds.l - UI_SIZE_CODE_MARGIN_GAP;
				marginBounds.l -= UI_SIZE_CODE_MARGIN + UI_SIZE_CODE_MARGIN_GAP;

				uint32_t marginColor = UIElementMessage(element, UI_MSG_CODE_GET_MARGIN_COLOR, i + 1, 0);

				if (marginColor) {
					UIDrawBlock(painter, marginBounds, marginColor);
				}

				UIDrawString(painter, marginBounds, string + p, 16 - p, ui.theme.codeDefault, UI_ALIGN_RIGHT, NULL);
			}

			if (code->focused == i) {
				UIDrawBlock(painter, lineBounds, ui.theme.codeFocused);
			}

			int x = UIDrawStringHighlighted(painter, lineBounds, code->content + code->lines[i].offset, code->lines[i].bytes, code->tabSize);
			int y = (lineBounds.t + lineBounds.b - UIMeasureStringHeight()) / 2;

			UICodeDecorateLine m = { 0 };
			m.x = x, m.y = y, m.bounds = lineBounds, m.index = i + 1, m.painter = painter;
			UIElementMessage(element, UI_MSG_CODE_DECORATE_LINE, 0, &m);

			lineBounds.t += lineHeight;
		}

		UIFontActivate(previousFont);
	} else if (message == UI_MSG_SCROLLED) {
		code->moveScrollToFocusNextLayout = false;
		UIElementRefresh(element);
	} else if (message == UI_MSG_MOUSE_WHEEL) {
		return UIElementMessage(&code->vScroll->e, message, di, dp);
	} else if (message == UI_MSG_GET_CURSOR) {
		if (UICodeHitTest(code, element->window->cursorX, element->window->cursorY) < 0) {
			return UI_CURSOR_FLIPPED_ARROW;
		}
	} else if (message == UI_MSG_DESTROY) {
		UI_FREE(code->content);
		UI_FREE(code->lines);
	}

	return 0;
}

void UICodeFocusLine(UICode *code, int index) {
	code->focused = index - 1;
	code->moveScrollToFocusNextLayout = true;
}

void UICodeInsertContent(UICode *code, const char *content, ptrdiff_t byteCount, bool replace) {
	UIFont *previousFont = UIFontActivate(code->font);

	if (byteCount == -1) {
		byteCount = _UIStringLength(content);
	}

	if (byteCount > 1000000000) {
		byteCount = 1000000000;
	}

	if (replace) {
		UI_FREE(code->content);
		UI_FREE(code->lines);
		code->content = NULL;
		code->lines = NULL;
		code->contentBytes = 0;
		code->lineCount = 0;
	}

	code->content = (char *) UI_REALLOC(code->content, code->contentBytes + byteCount);

	if (!byteCount) {
		return;
	}

	int lineCount = content[byteCount - 1] != '\n';

	for (int i = 0; i < byteCount; i++) {
		code->content[i + code->contentBytes] = content[i];

		if (content[i] == '\n') {
			lineCount++;
		}
	}

	code->lines = (UICodeLine *) UI_REALLOC(code->lines, sizeof(UICodeLine) * (code->lineCount + lineCount));
	int offset = 0, lineIndex = 0;

	for (intptr_t i = 0; i <= byteCount && lineIndex < lineCount; i++) {
		if (content[i] == '\n' || i == byteCount) {
			UICodeLine line = { 0 };
			line.offset = offset + code->contentBytes;
			line.bytes = i - offset;
			code->lines[code->lineCount + lineIndex] = line;
			lineIndex++;
			offset = i + 1;
		}
	}

	code->lineCount += lineCount;
	code->contentBytes += byteCount;

	if (!replace) {
		code->vScroll->position = code->lineCount * UIMeasureStringHeight();
	}

	UIFontActivate(previousFont);
}

UICode *UICodeCreate(UIElement *parent, uint32_t flags) {
	UICode *code = (UICode *) UIElementCreate(sizeof(UICode), parent, flags, _UICodeMessage, "Code");
	code->font = ui.activeFont;
	code->vScroll = UIScrollBarCreate(&code->e, 0);
	code->focused = -1;
	code->tabSize = 4;
	return code;
}

int _UIGaugeMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UIGauge *gauge = (UIGauge *) element;

	if (message == UI_MSG_GET_HEIGHT) {
		return UI_SIZE_GAUGE_HEIGHT * element->window->scale;
	} else if (message == UI_MSG_GET_WIDTH) {
		return UI_SIZE_GAUGE_WIDTH * element->window->scale;
	} else if (message == UI_MSG_PAINT) {
		UIPainter *painter = (UIPainter *) dp;
		UIDrawRectangle(painter, element->bounds, ui.theme.buttonNormal, ui.theme.border, UI_RECT_1(1));
		UIRectangle filled = UIRectangleAdd(element->bounds, UI_RECT_1I(1));
		filled.r = filled.l + UI_RECT_WIDTH(filled) * gauge->position;
		UIDrawBlock(painter, filled, ui.theme.selected);
	}

	return 0;
}

UIGauge *UIGaugeCreate(UIElement *parent, uint32_t flags) {
	return (UIGauge *) UIElementCreate(sizeof(UIGauge), parent, flags, _UIGaugeMessage, "Gauge");
}

int _UISliderMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UISlider *slider = (UISlider *) element;

	if (message == UI_MSG_GET_HEIGHT) {
		return UI_SIZE_SLIDER_HEIGHT * element->window->scale;
	} else if (message == UI_MSG_GET_WIDTH) {
		return UI_SIZE_SLIDER_WIDTH * element->window->scale;
	} else if (message == UI_MSG_PAINT) {
		UIPainter *painter = (UIPainter *) dp;
		UIRectangle bounds = element->bounds;
		int centerY = (bounds.t + bounds.b) / 2;
		int trackSize = UI_SIZE_SLIDER_TRACK * element->window->scale;
		int thumbSize = UI_SIZE_SLIDER_THUMB * element->window->scale;
		int thumbPosition = (UI_RECT_WIDTH(bounds) - thumbSize) * slider->position;
		UIRectangle track = UI_RECT_4(bounds.l, bounds.r, centerY - (trackSize + 1) / 2, centerY + trackSize / 2);
		UIDrawRectangle(painter, track, ui.theme.buttonNormal, ui.theme.border, UI_RECT_1(1));
		bool pressed = element == element->window->pressed;
		bool hovered = element == element->window->hovered;
		bool disabled = element->flags & UI_ELEMENT_DISABLED;
		uint32_t color = disabled ? ui.theme.buttonDisabled : pressed ? ui.theme.buttonPressed : hovered ? ui.theme.buttonHovered : ui.theme.buttonNormal;
		UIRectangle thumb = UI_RECT_4(bounds.l + thumbPosition, bounds.l + thumbPosition + thumbSize, centerY - (thumbSize + 1) / 2, centerY + thumbSize / 2);
		UIDrawRectangle(painter, thumb, color, ui.theme.border, UI_RECT_1(1));
	} else if (message == UI_MSG_LEFT_DOWN || (message == UI_MSG_MOUSE_DRAG && element->window->pressedButton == 1)) {
		UIRectangle bounds = element->bounds;
		int thumbSize = UI_SIZE_SLIDER_THUMB * element->window->scale;
		slider->position = (float) (element->window->cursorX - thumbSize / 2 - bounds.l) / (UI_RECT_WIDTH(bounds) - thumbSize);
		if (slider->steps > 1) slider->position = (int) (slider->position * (slider->steps - 1) + 0.5f) / (float) (slider->steps - 1);
		if (slider->position < 0) slider->position = 0;
		if (slider->position > 1) slider->position = 1;
		UIElementMessage(element, UI_MSG_VALUE_CHANGED, 0, 0);
		UIElementRepaint(element, NULL);
	} else if (message == UI_MSG_UPDATE) {
		UIElementRepaint(element, NULL);
	}

	return 0;
}

UISlider *UISliderCreate(UIElement *parent, uint32_t flags) {
	return (UISlider *) UIElementCreate(sizeof(UISlider), parent, flags, _UISliderMessage, "Slider");
}

int UITableHitTest(UITable *table, int x, int y) {
	x -= table->e.bounds.l;

	if (x < 0 || x >= UI_RECT_WIDTH(table->e.bounds) - UI_SIZE_SCROLL_BAR * table->e.window->scale) {
		return -1;
	}

	y -= (table->e.bounds.t + UI_SIZE_TABLE_HEADER * table->e.window->scale) - table->vScroll->position;

	int rowHeight = UI_SIZE_TABLE_ROW * table->e.window->scale;

	if (y < 0 || y >= rowHeight * table->itemCount) {
		return -1;
	}

	return y / rowHeight;
}

int UITableHeaderHitTest(UITable *table, int x, int y) {
	if (!table->columnCount) return -1;
	UIRectangle header = table->e.bounds;
	header.b = header.t + UI_SIZE_TABLE_HEADER * table->e.window->scale;
	header.l += UI_SIZE_TABLE_COLUMN_GAP * table->e.window->scale;
	int position = 0, index = 0;

	while (true) {
		int end = position;
		for (; table->columns[end] != '\t' && table->columns[end]; end++);
		header.r = header.l + table->columnWidths[index];
		if (UIRectangleContains(header, x, y)) return index;
		header.l += table->columnWidths[index] + UI_SIZE_TABLE_COLUMN_GAP * table->e.window->scale;
		if (table->columns[end] != '\t') break;
		position = end + 1, index++;
	}

	return -1;
}

bool UITableEnsureVisible(UITable *table, int index) {
	int rowHeight = UI_SIZE_TABLE_ROW * table->e.window->scale;
	int y = index * rowHeight;
	y -= table->vScroll->position;
	int height = UI_RECT_HEIGHT(table->e.bounds) - UI_SIZE_TABLE_HEADER * table->e.window->scale - rowHeight;

	if (y < 0) {
		table->vScroll->position += y;
		UIElementRefresh(&table->e);
		return true;
	} else if (y > height) {
		table->vScroll->position -= height - y;
		UIElementRefresh(&table->e);
		return true;
	} else {
		return false;
	}
}

void UITableResizeColumns(UITable *table) {
	int position = 0;
	int count = 0;

	while (true) {
		int end = position;
		for (; table->columns[end] != '\t' && table->columns[end]; end++);
		count++;
		if (table->columns[end] == '\t') position = end + 1;
		else break;
	}

	UI_FREE(table->columnWidths);
	table->columnWidths = (int *) UI_MALLOC(count * sizeof(int));
	table->columnCount = count;

	position = 0;

	char buffer[256];
	UITableGetItem m = { 0 };
	m.buffer = buffer;
	m.bufferBytes = sizeof(buffer);

	while (true) {
		int end = position;
		for (; table->columns[end] != '\t' && table->columns[end]; end++);

		int longest = UIMeasureStringWidth(table->columns + position, end - position);

		for (int i = 0; i < table->itemCount; i++) {
			m.index = i;
			int bytes = UIElementMessage(&table->e, UI_MSG_TABLE_GET_ITEM, 0, &m);
			int width = UIMeasureStringWidth(buffer, bytes);

			if (width > longest) {
				longest = width;
			}
		}

		table->columnWidths[m.column] = longest;
		m.column++;
		if (table->columns[end] == '\t') position = end + 1;
		else break;
	}
}

int _UITableMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UITable *table = (UITable *) element;

	if (message == UI_MSG_PAINT) {
		UIPainter *painter = (UIPainter *) dp;
		UIRectangle bounds = element->bounds;
		bounds.r -= UI_SIZE_SCROLL_BAR * element->window->scale;
		UIDrawBlock(painter, bounds, ui.theme.panel2);
		char buffer[256];
		UIRectangle row = bounds;
		int rowHeight = UI_SIZE_TABLE_ROW * element->window->scale;
		UITableGetItem m = { 0 };
		m.buffer = buffer;
		m.bufferBytes = sizeof(buffer);
		row.t += UI_SIZE_TABLE_HEADER * table->e.window->scale;
		row.t -= (int64_t) table->vScroll->position % rowHeight;
		int hovered = UITableHitTest(table, element->window->cursorX, element->window->cursorY);

		for (int i = table->vScroll->position / rowHeight; i < table->itemCount; i++) {
			if (row.t > element->clip.b) {
				break;
			}
			
			row.b = row.t + rowHeight;
			m.index = i;
			m.isSelected = false;
			m.column = 0;
			int bytes = UIElementMessage(element, UI_MSG_TABLE_GET_ITEM, 0, &m);
			uint32_t textColor = ui.theme.text;

			if (m.isSelected) {
				UIDrawBlock(painter, row, ui.theme.selected);
				textColor = ui.theme.textSelected;
			} else if (hovered == i) {
				UIDrawBlock(painter, row, ui.theme.buttonHovered);
			}

			UIRectangle cell = row;
			cell.l += UI_SIZE_TABLE_COLUMN_GAP * table->e.window->scale;

			for (int j = 0; j < table->columnCount; j++) {
				if (j) {
					m.column = j;
					bytes = UIElementMessage(element, UI_MSG_TABLE_GET_ITEM, 0, &m);
				}

				cell.r = cell.l + table->columnWidths[j];
				if ((size_t) bytes > m.bufferBytes && bytes > 0) bytes = m.bufferBytes;
				UIDrawString(painter, cell, buffer, bytes, textColor, UI_ALIGN_LEFT, NULL);
				cell.l += table->columnWidths[j] + UI_SIZE_TABLE_COLUMN_GAP * table->e.window->scale;
			}

			row.t += rowHeight;
		}

		UIRectangle header = bounds;
		header.b = header.t + UI_SIZE_TABLE_HEADER * table->e.window->scale;
		UIDrawRectangle(painter, header, ui.theme.panel1, ui.theme.border, UI_RECT_4(0, 0, 0, 1));
		header.l += UI_SIZE_TABLE_COLUMN_GAP * table->e.window->scale;

		int position = 0;
		int index = 0;

		if (table->columnCount) {
			while (true) {
				int end = position;
				for (; table->columns[end] != '\t' && table->columns[end]; end++);

				header.r = header.l + table->columnWidths[index];
				UIDrawString(painter, header, table->columns + position, end - position, ui.theme.text, UI_ALIGN_LEFT, NULL);
				if (index == table->columnHighlight) UIDrawInvert(painter, header);
				header.l += table->columnWidths[index] + UI_SIZE_TABLE_COLUMN_GAP * table->e.window->scale;

				if (table->columns[end] == '\t') {
					position = end + 1;
					index++;
				} else {
					break;
				}
			}
		}
	} else if (message == UI_MSG_LAYOUT) {
		UIRectangle scrollBarBounds = element->bounds;
		scrollBarBounds.l = scrollBarBounds.r - UI_SIZE_SCROLL_BAR * element->window->scale;
		table->vScroll->maximum = table->itemCount * UI_SIZE_TABLE_ROW * element->window->scale;
		table->vScroll->page = UI_RECT_HEIGHT(element->bounds) - UI_SIZE_TABLE_HEADER * table->e.window->scale;
		UIElementMove(&table->vScroll->e, scrollBarBounds, true);
	} else if (message == UI_MSG_MOUSE_MOVE || message == UI_MSG_UPDATE) {
		UIElementRepaint(element, NULL);
	} else if (message == UI_MSG_SCROLLED) {
		UIElementRefresh(element);
	} else if (message == UI_MSG_MOUSE_WHEEL) {
		return UIElementMessage(&table->vScroll->e, message, di, dp);
	} else if (message == UI_MSG_DESTROY) {
		UI_FREE(table->columns);
		UI_FREE(table->columnWidths);
	}

	return 0;
}

UITable *UITableCreate(UIElement *parent, uint32_t flags, const char *columns) {
	UITable *table = (UITable *) UIElementCreate(sizeof(UITable), parent, flags, _UITableMessage, "Table");
	table->vScroll = UIScrollBarCreate(&table->e, 0);
	table->columns = UIStringCopy(columns, -1);
	table->columnHighlight = -1;
	return table;
}

void UITextboxReplace(UITextbox *textbox, const char *text, ptrdiff_t bytes, bool sendChangedMessage) {
	if (bytes == -1) {
		bytes = _UIStringLength(text);
	}

	int deleteFrom = textbox->carets[0], deleteTo = textbox->carets[1];

	if (deleteFrom > deleteTo) {
		UI_SWAP(int, deleteFrom, deleteTo);
	}

	for (int i = deleteTo; i < textbox->bytes; i++) {
		textbox->string[i - deleteTo + deleteFrom] = textbox->string[i];
	}

	textbox->bytes -= deleteTo - deleteFrom;
	textbox->carets[0] = textbox->carets[1] = deleteFrom;

	textbox->string = (char *) UI_REALLOC(textbox->string, textbox->bytes + bytes);

	for (int i = textbox->bytes + bytes - 1; i >= textbox->carets[0] + bytes; i--) {
		textbox->string[i] = textbox->string[i - bytes];
	}

	for (int i = textbox->carets[0]; i < textbox->carets[0] + bytes; i++) {
		textbox->string[i] = text[i - textbox->carets[0]];
	}

	textbox->bytes += bytes;
	textbox->carets[0] += bytes;
	textbox->carets[1] = textbox->carets[0];

	if (sendChangedMessage) {
		UIElementMessage(&textbox->e, UI_MSG_VALUE_CHANGED, 0, 0);
	}

	textbox->e.window->textboxModifiedFlag = true;
}

void UITextboxClear(UITextbox *textbox, bool sendChangedMessage) {
	textbox->carets[1] = 0;
	textbox->carets[0] = textbox->bytes;
	UITextboxReplace(textbox, "", 0, sendChangedMessage);
}

void UITextboxMoveCaret(UITextbox *textbox, bool backward, bool word) {
	while (true) {
		if (textbox->carets[0] > 0 && backward) {
			textbox->carets[0]--;
		} else if (textbox->carets[0] < textbox->bytes && !backward) {
			textbox->carets[0]++;
		} else {
			return;
		}

		if (!word) {
			return;
		} else if (textbox->carets[0] != textbox->bytes && textbox->carets[0] != 0) {
			char c1 = textbox->string[textbox->carets[0] - 1];
			char c2 = textbox->string[textbox->carets[0]];

			if (_UICharIsAlphaOrDigitOrUnderscore(c1) != _UICharIsAlphaOrDigitOrUnderscore(c2)) {
				return;
			}
		}
	}
}

int _UITextboxMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UITextbox *textbox = (UITextbox *) element;

	if (message == UI_MSG_GET_HEIGHT) {
		return UI_SIZE_TEXTBOX_HEIGHT * element->window->scale;
	} else if (message == UI_MSG_GET_WIDTH) {
		return UI_SIZE_TEXTBOX_WIDTH * element->window->scale;
	} else if (message == UI_MSG_PAINT) {
		int scaledMargin = UI_SIZE_TEXTBOX_MARGIN * element->window->scale;
		int totalWidth = UIMeasureStringWidth(textbox->string, textbox->bytes) + scaledMargin * 2;
		UIRectangle textBounds = UIRectangleAdd(element->bounds, UI_RECT_1I(scaledMargin));

		if (textbox->scroll > totalWidth - UI_RECT_WIDTH(textBounds)) {
			textbox->scroll = totalWidth - UI_RECT_WIDTH(textBounds);
		}

		if (textbox->scroll < 0) {
			textbox->scroll = 0;
		}

		int caretX = UIMeasureStringWidth(textbox->string, textbox->carets[0]) - textbox->scroll;

		if (caretX < 0) {
			textbox->scroll = caretX + textbox->scroll;
		} else if (caretX > UI_RECT_WIDTH(textBounds)) {
			textbox->scroll = caretX - UI_RECT_WIDTH(textBounds) + textbox->scroll + 1;
		}

		UIPainter *painter = (UIPainter *) dp;
		bool focused = element->window->focused == element;
		bool disabled = element->flags & UI_ELEMENT_DISABLED;
		UIDrawRectangle(painter, element->bounds, 
			disabled ? ui.theme.buttonDisabled : focused ? ui.theme.textboxFocused : ui.theme.textboxNormal, 
			ui.theme.border, UI_RECT_1(1));
#ifdef __cplusplus
		UIStringSelection selection = {};
#else
		UIStringSelection selection = { 0 };
#endif
		selection.carets[0] = textbox->carets[0];
		selection.carets[1] = textbox->carets[1];
		selection.colorBackground = ui.theme.selected;
		selection.colorText = ui.theme.textSelected;
		textBounds.l -= textbox->scroll;
		UIDrawString(painter, textBounds, textbox->string, textbox->bytes, 
			disabled ? ui.theme.textDisabled : ui.theme.text, UI_ALIGN_LEFT, focused ? &selection : NULL);
	} else if (message == UI_MSG_GET_CURSOR) {
		return UI_CURSOR_TEXT;
	} else if (message == UI_MSG_LEFT_DOWN) {
		UIElementFocus(element);
	} else if (message == UI_MSG_UPDATE) {
		UIElementRepaint(element, NULL);
	} else if (message == UI_MSG_DESTROY) {
		UI_FREE(textbox->string);
	} else if (message == UI_MSG_KEY_TYPED) {
		UIKeyTyped *m = (UIKeyTyped *) dp;
		bool handled = true;

		if (textbox->rejectNextKey) {
			textbox->rejectNextKey = false;
			handled = false;
		} else if (m->code == UI_KEYCODE_BACKSPACE || m->code == UI_KEYCODE_DELETE) {
			if (textbox->carets[0] == textbox->carets[1]) {
				UITextboxMoveCaret(textbox, m->code == UI_KEYCODE_BACKSPACE, element->window->ctrl);
			}

			UITextboxReplace(textbox, NULL, 0, true);
		} else if (m->code == UI_KEYCODE_LEFT || m->code == UI_KEYCODE_RIGHT) {
			UITextboxMoveCaret(textbox, m->code == UI_KEYCODE_LEFT, element->window->ctrl);

			if (!element->window->shift) {
				textbox->carets[1] = textbox->carets[0];
			}
		} else if (m->code == UI_KEYCODE_HOME || m->code == UI_KEYCODE_END) {
			if (m->code == UI_KEYCODE_HOME) {
				textbox->carets[0] = 0;
			} else {
				textbox->carets[0] = textbox->bytes;
			}

			if (!element->window->shift) {
				textbox->carets[1] = textbox->carets[0];
			}
		} else if (m->code == UI_KEYCODE_LETTER('A') && element->window->ctrl) {
			textbox->carets[1] = 0;
			textbox->carets[0] = textbox->bytes;
		} else if (m->textBytes && !element->window->alt && !element->window->ctrl && m->text[0] >= 0x20) {
			UITextboxReplace(textbox, m->text, m->textBytes, true);
		} else {
			handled = false;
		}

		if (handled) {
			UIElementRepaint(element, NULL);
			return 1;
		}
	}

	return 0;
}

UITextbox *UITextboxCreate(UIElement *parent, uint32_t flags) {
	return (UITextbox *) UIElementCreate(sizeof(UITextbox), parent, flags | UI_ELEMENT_TAB_STOP, _UITextboxMessage, "Textbox");
}

int _UIColorCircleMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UIColorPicker *colorPicker = (UIColorPicker *) element->parent;

	if (message == UI_MSG_PAINT) {
		UIPainter *painter = (UIPainter *) dp;

		int startY = element->bounds.t, endY = element->bounds.b;
		int startX = element->bounds.l, endX = element->bounds.r;
		int size = endY - startY;

		for (int i = startY; i < endY; i++) {
			uint32_t *out = painter->bits + i * painter->width + startX;
			int j = startX;
			float y0 = i - startY - size / 2, x0 = -size / 2;
			float angle = _UIArcTan2Float((i - startY) * 2.0f / size - 1, -1);

			do {
				float distanceFromCenterSquared = x0 * x0 + y0 * y0;
				float hue = (angle + 3.14159f) * 0.954929658f;
				float saturation = _UISquareRootFloat(distanceFromCenterSquared * 4.0f / size / size);

				if (saturation <= 1 && UIRectangleContains(painter->clip, j, i)) {
					UIColorToRGB(hue, saturation, colorPicker->value, out);
					*out |= 0xFF000000;
				}

				out++, j++, x0++;

				if (distanceFromCenterSquared) {
					angle -= y0 / distanceFromCenterSquared;
				} else {
					angle = _UIArcTan2Float((i - startY) * 2.0f / size - 1, 0.01f);
				}
			} while (j < endX);
		}

		float angle = colorPicker->hue / 0.954929658f - 3.14159f;
		float radius = colorPicker->saturation * size / 2;
		int cx = (startX + endX) / 2 + radius * _UICosFloat(angle);
		int cy = (startY + endY) / 2 + radius * _UISinFloat(angle);
		UIDrawInvert(painter, UI_RECT_4(cx - 1, cx + 1, startY, endY));
		UIDrawInvert(painter, UI_RECT_4(startX, endX, cy - 1, cy + 1));
	} else if (message == UI_MSG_GET_CURSOR) {
		return UI_CURSOR_CROSS_HAIR;
	} else if (message == UI_MSG_LEFT_DOWN || message == UI_MSG_MOUSE_DRAG) {
		int startY = element->bounds.t, endY = element->bounds.b, cursorY = element->window->cursorY;
		int startX = element->bounds.l, endX = element->bounds.r, cursorX = element->window->cursorX;
		int dx = (startX + endX) / 2, dy = (startY + endY) / 2;
		int size = endY - startY;

		float angle = _UIArcTan2Float((cursorY - startY) * 2.0f / size - 1, (cursorX - startX) * 2.0f / size - 1);
		float distanceFromCenterSquared = (cursorX - dx) * (cursorX - dx) + (cursorY - dy) * (cursorY - dy);
		colorPicker->hue = (angle + 3.14159f) * 0.954929658f;
		colorPicker->saturation = _UISquareRootFloat(distanceFromCenterSquared * 4.0f / size / size);;
		if (colorPicker->saturation > 1) colorPicker->saturation = 1;

		UIElementMessage(&colorPicker->e, UI_MSG_VALUE_CHANGED, 0, 0);
		UIElementRepaint(&colorPicker->e, NULL);
	}

	return 0;
}

int _UIColorSliderMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UIColorPicker *colorPicker = (UIColorPicker *) element->parent;
	float opacitySlider = element->flags & 1;

	if (message == UI_MSG_PAINT) {
		UIPainter *painter = (UIPainter *) dp;

		int startY = element->bounds.t, endY = element->bounds.b;
		int startX = element->bounds.l, endX = element->bounds.r;
		int size = endY - startY;

		for (int i = startY; i < endY; i++) {
			if (i < painter->clip.t || i >= painter->clip.b) continue;
			uint32_t *out = painter->bits + i * painter->width + startX;
			int j = element->clip.l;
			uint32_t color;
			float p = 1.0f - (float) (i - startY) / size;

			if (opacitySlider) {
				UIColorToRGB(colorPicker->hue, colorPicker->saturation, colorPicker->value, &color);
				color = UI_COLOR_FROM_FLOAT(p * (UI_COLOR_RED_F(color) - 0.5f) + 0.5f, 
					p * (UI_COLOR_GREEN_F(color) - 0.5f) + 0.5f, 
					p * (UI_COLOR_BLUE_F(color) - 0.5f) + 0.5f);
			} else {
				UIColorToRGB(colorPicker->hue, colorPicker->saturation, p, &color);
			}

			color |= 0xFF000000;

			do {
				*out = color;
				out++, j++;
			} while (j < element->clip.r);
		}

		int cy = (size - 1) * (1 - (opacitySlider ? colorPicker->opacity : colorPicker->value)) + startY;
		UIDrawInvert(painter, UI_RECT_4(startX, endX, cy - 1, cy + 1));
	} else if (message == UI_MSG_GET_CURSOR) {
		return UI_CURSOR_CROSS_HAIR;
	} else if (message == UI_MSG_LEFT_DOWN || message == UI_MSG_MOUSE_DRAG) {
		int startY = element->bounds.t, endY = element->bounds.b, cursorY = element->window->cursorY;
		float *value = opacitySlider ? &colorPicker->opacity : &colorPicker->value;
		*value = 1 - (float) (cursorY - startY) / (endY - startY);
		if (*value < 0) *value = 0;
		if (*value > 1) *value = 1;
		UIElementMessage(&colorPicker->e, UI_MSG_VALUE_CHANGED, 0, 0);
		UIElementRepaint(&colorPicker->e, NULL);
	}

	return 0;
}

int _UIColorPickerMessage(UIElement *element, UIMessage message, int di, void *dp) {
	bool hasOpacity = element->flags & UI_COLOR_PICKER_HAS_OPACITY;

	if (message == UI_MSG_GET_WIDTH) {
		return (hasOpacity ? 280 : 240) * element->window->scale;
	} else if (message == UI_MSG_GET_HEIGHT) {
		return 200 * element->window->scale;
	} else if (message == UI_MSG_LAYOUT) {
		UIRectangle bounds = element->bounds;

		int sliderSize = 35 * element->window->scale;
		int gap = 5 * element->window->scale;

		if (hasOpacity) {
			UIElementMove(element->children, UI_RECT_4(bounds.l, bounds.r - (sliderSize + gap) * 2, bounds.t, bounds.b), false);
			UIElementMove(element->children->next, UI_RECT_4(bounds.r - sliderSize * 2 - gap, bounds.r - sliderSize - gap, bounds.t, bounds.b), false);
			UIElementMove(element->children->next->next, UI_RECT_4(bounds.r - sliderSize, bounds.r, bounds.t, bounds.b), false);
		} else {
			UIElementMove(element->children, UI_RECT_4(bounds.l, bounds.r - sliderSize - gap, bounds.t, bounds.b), false);
			UIElementMove(element->children->next, UI_RECT_4(bounds.r - sliderSize, bounds.r, bounds.t, bounds.b), false);
		}
	}

	return 0;
}

UIColorPicker *UIColorPickerCreate(UIElement *parent, uint32_t flags) {
	UIColorPicker *colorPicker = (UIColorPicker *) UIElementCreate(sizeof(UIColorPicker), parent, flags, _UIColorPickerMessage, "ColorPicker");
	UIElementCreate(sizeof(UIElement), &colorPicker->e, 0, _UIColorCircleMessage, "ColorCircle");
	UIElementCreate(sizeof(UIElement), &colorPicker->e, 0, _UIColorSliderMessage, "ColorSlider");

	if (flags & UI_COLOR_PICKER_HAS_OPACITY) {
		UIElementCreate(sizeof(UIElement), &colorPicker->e, 1, _UIColorSliderMessage, "ColorSlider");
	}

	return colorPicker;
}

#define UI_MDI_CHILD_CALCULATE_LAYOUT() \
	int titleSize = UI_SIZE_MDI_CHILD_TITLE * element->window->scale; \
	int borderSize = UI_SIZE_MDI_CHILD_BORDER * element->window->scale; \
	UIRectangle title = UIRectangleAdd(element->bounds, UI_RECT_4(borderSize, -borderSize, 0, 0)); \
	title.b = title.t + titleSize; \
	UIRectangle content = UIRectangleAdd(element->bounds, UI_RECT_4(borderSize, -borderSize, titleSize, -borderSize));

int _UIMDIChildHitTest(UIMDIChild *mdiChild, int x, int y) {
	UIElement *element = &mdiChild->e;
	UI_MDI_CHILD_CALCULATE_LAYOUT();
	int cornerSize = UI_SIZE_MDI_CHILD_CORNER * element->window->scale;
	if (!UIRectangleContains(element->bounds, x, y) || UIRectangleContains(content, x, y)) return -1;
	else if (x < element->bounds.l + cornerSize && y < element->bounds.t + cornerSize) return 0b1010;
	else if (x > element->bounds.r - cornerSize && y < element->bounds.t + cornerSize) return 0b0110;
	else if (x < element->bounds.l + cornerSize && y > element->bounds.b - cornerSize) return 0b1001;
	else if (x > element->bounds.r - cornerSize && y > element->bounds.b - cornerSize) return 0b0101;
	else if (x < element->bounds.l + borderSize) return 0b1000;
	else if (x > element->bounds.r - borderSize) return 0b0100;
	else if (y < element->bounds.t + borderSize) return 0b0010;
	else if (y > element->bounds.b - borderSize) return 0b0001;
	else if (UIRectangleContains(title, x, y)) return 0b1111;
	else return -1;
}

void _UIMDIChildCloseButton(void *_child) {
	UIElement *child = (UIElement *) _child;
	
	if (!UIElementMessage(child, UI_MSG_WINDOW_CLOSE, 0, 0)) {
		UIElementDestroy(child);
		UIElementRefresh(child->parent);
	}
}

int _UIMDIChildMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UIMDIChild *mdiChild = (UIMDIChild *) element;

	if (message == UI_MSG_PAINT) {
		UI_MDI_CHILD_CALCULATE_LAYOUT();
		UIPainter *painter = (UIPainter *) dp;
		UIRectangle borders = UI_RECT_4(borderSize, borderSize, titleSize, borderSize);
		UIDrawBorder(painter, element->bounds, ui.theme.buttonNormal, borders);
		UIDrawBorder(painter, element->bounds, ui.theme.border, UI_RECT_1((int) element->window->scale));
		UIDrawBorder(painter, UIRectangleAdd(content, UI_RECT_1I(-1)), ui.theme.border, UI_RECT_1((int) element->window->scale));
		UIDrawString(painter, title, mdiChild->title, mdiChild->titleBytes, ui.theme.text, UI_ALIGN_LEFT, NULL);
	} else if (message == UI_MSG_GET_WIDTH) {
		UIElement *child = element->children;
		while (child && child->next) child = child->next;
		int width = 2 * UI_SIZE_MDI_CHILD_BORDER;
		width += (child ? UIElementMessage(child, message, di ? (di - UI_SIZE_MDI_CHILD_TITLE + UI_SIZE_MDI_CHILD_BORDER) : 0, dp) : 0);
		if (width < UI_SIZE_MDI_CHILD_MINIMUM_WIDTH) width = UI_SIZE_MDI_CHILD_MINIMUM_WIDTH;
		return width;
	} else if (message == UI_MSG_GET_HEIGHT) {
		UIElement *child = element->children;
		while (child && child->next) child = child->next;
		int height = UI_SIZE_MDI_CHILD_TITLE + UI_SIZE_MDI_CHILD_BORDER;
		height += (child ? UIElementMessage(child, message, di ? (di - 2 * UI_SIZE_MDI_CHILD_BORDER) : 0, dp) : 0);
		if (height < UI_SIZE_MDI_CHILD_MINIMUM_HEIGHT) height = UI_SIZE_MDI_CHILD_MINIMUM_HEIGHT;
		return height;
	} else if (message == UI_MSG_LAYOUT) {
		UI_MDI_CHILD_CALCULATE_LAYOUT();

		UIElement *child = element->children;
		int position = title.r;

		while (child && child->next) {
			int width = UIElementMessage(child, UI_MSG_GET_WIDTH, 0, 0);
			UIElementMove(child, UI_RECT_4(position - width, position, title.t, title.b), false);
			position -= width, child = child->next;
		}

		if (child) {
			UIElementMove(child, content, false);
		}
	} else if (message == UI_MSG_GET_CURSOR) {
		int hitTest = _UIMDIChildHitTest(mdiChild, element->window->cursorX, element->window->cursorY);
		if (hitTest == 0b1000) return UI_CURSOR_RESIZE_LEFT;
		if (hitTest == 0b0010) return UI_CURSOR_RESIZE_UP;
		if (hitTest == 0b0110) return UI_CURSOR_RESIZE_UP_RIGHT;
		if (hitTest == 0b1010) return UI_CURSOR_RESIZE_UP_LEFT;
		if (hitTest == 0b0100) return UI_CURSOR_RESIZE_RIGHT;
		if (hitTest == 0b0001) return UI_CURSOR_RESIZE_DOWN;
		if (hitTest == 0b1001) return UI_CURSOR_RESIZE_DOWN_LEFT;
		if (hitTest == 0b0101) return UI_CURSOR_RESIZE_DOWN_RIGHT;
		return UI_CURSOR_ARROW;
	} else if (message == UI_MSG_LEFT_DOWN) {
		mdiChild->dragHitTest = _UIMDIChildHitTest(mdiChild, element->window->cursorX, element->window->cursorY);
		mdiChild->dragOffset = UIRectangleAdd(element->bounds, UI_RECT_2(-element->window->cursorX, -element->window->cursorY));
	} else if (message == UI_MSG_LEFT_UP) {
		if (mdiChild->bounds.l < 0) mdiChild->bounds.r -= mdiChild->bounds.l, mdiChild->bounds.l = 0;
		if (mdiChild->bounds.t < 0) mdiChild->bounds.b -= mdiChild->bounds.t, mdiChild->bounds.t = 0;
		UIElementRefresh(element->parent);
	} else if (message == UI_MSG_MOUSE_DRAG) {
		if (mdiChild->dragHitTest > 0) {
#define _UI_MDI_CHILD_MOVE_EDGE(bit, edge, cursor, size, opposite, negate, minimum, offset) \
	if (mdiChild->dragHitTest & bit) mdiChild->bounds.edge = mdiChild->dragOffset.edge + element->window->cursor - element->parent->bounds.offset; \
	if ((mdiChild->dragHitTest & bit) && size(mdiChild->bounds) < minimum) mdiChild->bounds.edge = mdiChild->bounds.opposite negate minimum;
			_UI_MDI_CHILD_MOVE_EDGE(0b1000, l, cursorX, UI_RECT_WIDTH, r, -, UI_SIZE_MDI_CHILD_MINIMUM_WIDTH, l);
			_UI_MDI_CHILD_MOVE_EDGE(0b0100, r, cursorX, UI_RECT_WIDTH, l, +, UI_SIZE_MDI_CHILD_MINIMUM_WIDTH, l);
			_UI_MDI_CHILD_MOVE_EDGE(0b0010, t, cursorY, UI_RECT_HEIGHT, b, -, UI_SIZE_MDI_CHILD_MINIMUM_HEIGHT, t);
			_UI_MDI_CHILD_MOVE_EDGE(0b0001, b, cursorY, UI_RECT_HEIGHT, t, +, UI_SIZE_MDI_CHILD_MINIMUM_HEIGHT, t);
			UIElementRefresh(element->parent);
		}
	} else if (message == UI_MSG_DESTROY) {
		UI_FREE(mdiChild->title);
		UIMDIClient *client = (UIMDIClient *) element->parent;
		if (client->e.children == element) client->e.children = element->next;
		if (mdiChild->previous) mdiChild->previous->e.next = element->next;
		if (element->next) ((UIMDIChild *) element->next)->previous = mdiChild->previous;
		if (client->active == mdiChild) client->active = mdiChild->previous;
	}

	return 0;
}

int _UIMDIClientMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UIMDIClient *client = (UIMDIClient *) element;

	if (message == UI_MSG_PAINT) {
		UIDrawBlock((UIPainter *) dp, element->bounds, (element->flags & UI_MDI_CLIENT_TRANSPARENT) ? 0 : ui.theme.panel2);
	} else if (message == UI_MSG_LAYOUT) {
		UIElement *child = element->children;

		while (child) {
			UI_ASSERT(child->messageClass == _UIMDIChildMessage);

			UIMDIChild *mdiChild = (UIMDIChild *) child;

			if (UIRectangleEquals(mdiChild->bounds, UI_RECT_1(0))) {
				int width = UIElementMessage(&mdiChild->e, UI_MSG_GET_WIDTH, 0, 0);
				int height = UIElementMessage(&mdiChild->e, UI_MSG_GET_HEIGHT, width, 0);
				if (client->cascade + width > element->bounds.r || client->cascade + height > element->bounds.b) client->cascade = 0;
				mdiChild->bounds = UI_RECT_4(client->cascade, client->cascade + width, client->cascade, client->cascade + height);
				client->cascade += UI_SIZE_MDI_CASCADE * element->window->scale;
			}

			UIRectangle bounds = UIRectangleAdd(mdiChild->bounds, UI_RECT_2(element->bounds.l, element->bounds.t));
			UIElementMove(child, bounds, false);
			child = child->next;
		}
	} else if (message == UI_MSG_FIND_BY_POINT) {
		UIFindByPoint *m = (UIFindByPoint *) dp;
		UIMDIChild *child = client->active;

		while (child) {
			if (UIRectangleContains(child->e.bounds, m->x, m->y)) {
				m->result = UIElementFindByPoint(&child->e, m->x, m->y);
				return 1;
			}

			child = child->previous;
		}

		return 1;
	} else if (message == UI_MSG_PRESSED_DESCENDENT) {
		UIMDIChild *child = (UIMDIChild *) dp;

		if (child && child != client->active) {
			if (client->e.children == &child->e) client->e.children = child->e.next;
			if (child->previous) child->previous->e.next = child->e.next;
			if (child->e.next) ((UIMDIChild *) child->e.next)->previous = child->previous;
			if (client->active) client->active->e.next = &child->e;
			child->previous = client->active;
			child->e.next = NULL;
			client->active = child;
			((UIMDIChild *) client->e.children)->previous = NULL;
			UIElementRefresh(element);
		}
	}

	return 0;
}

UIMDIChild *UIMDIChildCreate(UIElement *parent, uint32_t flags, UIRectangle initialBounds, const char *title, ptrdiff_t titleBytes) {
	UI_ASSERT(parent->messageClass == _UIMDIClientMessage);

	UIMDIChild *mdiChild = (UIMDIChild *) UIElementCreate(sizeof(UIMDIChild), parent, flags, _UIMDIChildMessage, "MDIChild");
	UIMDIClient *mdiClient = (UIMDIClient *) parent;

	mdiChild->bounds = initialBounds;
	mdiChild->title = UIStringCopy(title, (mdiChild->titleBytes = titleBytes));
	mdiChild->previous = mdiClient->active;
	mdiClient->active = mdiChild;

	if (flags & UI_MDI_CHILD_CLOSE_BUTTON) {
		UIButton *closeButton = UIButtonCreate(&mdiChild->e, UI_BUTTON_SMALL | UI_ELEMENT_NON_CLIENT, "X", 1);
		closeButton->invoke = _UIMDIChildCloseButton;
		closeButton->e.cp = mdiChild;
	}

	return mdiChild;
}

UIMDIClient *UIMDIClientCreate(UIElement *parent, uint32_t flags) {
	return (UIMDIClient *) UIElementCreate(sizeof(UIMDIClient), parent, flags, _UIMDIClientMessage, "MDIClient");
}

int _UIExpandPaneMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UIExpandPane *pane = (UIExpandPane *) element;
	
	if (message == UI_MSG_GET_HEIGHT) {
		int height = UIElementMessage(&pane->button->e, message, di, dp);

		if (pane->expanded) {
			height += UIElementMessage(&pane->panel->e, message, di, dp);
		}

		return height;
	} else if (message == UI_MSG_LAYOUT) {
		UIRectangle bounds = pane->e.bounds;
		int buttonHeight = UIElementMessage(&pane->button->e, UI_MSG_GET_HEIGHT, UI_RECT_WIDTH(bounds), NULL);
		UIElementMove(&pane->button->e, UI_RECT_4(bounds.l, bounds.r, bounds.t, bounds.t + buttonHeight), false);

		if (pane->expanded) {
			pane->panel->e.flags &= ~UI_ELEMENT_HIDE;
			UIElementMove(&pane->panel->e, UI_RECT_4(bounds.l, bounds.r, bounds.t + buttonHeight, bounds.b), false);
		} else {
			pane->panel->e.flags |= UI_ELEMENT_HIDE;
		}
	} else if (message == UI_MSG_CLIENT_PARENT) {
		*(UIElement **) dp = &pane->panel->e;
	}

	return 0;
}

void _UIExpandPaneButtonInvoke(void *cp) {
	UIExpandPane *pane = (UIExpandPane *) cp;
	pane->expanded = !pane->expanded;
	if (pane->expanded) pane->button->e.flags |= UI_BUTTON_CHECKED;
	else pane->button->e.flags &= ~UI_BUTTON_CHECKED;

	UIElement *ancestor = &pane->e;

	while (ancestor) {
		UIElementRefresh(ancestor);

		if ((ancestor->messageClass == _UIPanelMessage && (ancestor->flags & UI_PANEL_SCROLL)) 
				|| (ancestor->messageClass == _UIMDIChildMessage)
				|| (ancestor->flags & UI_ELEMENT_V_FILL)) {
			break;
		}

		ancestor = ancestor->parent;
	}
}

UIExpandPane *UIExpandPaneCreate(UIElement *parent, uint32_t flags, const char *label, ptrdiff_t labelBytes, uint32_t panelFlags) {
	UIExpandPane *pane = (UIExpandPane *) UIElementCreate(sizeof(UIExpandPane), parent, flags, _UIExpandPaneMessage, "ExpandPane");
	pane->button = UIButtonCreate(parent, UI_ELEMENT_NON_CLIENT, label, labelBytes);
	pane->button->e.cp = pane;
	pane->button->invoke = _UIExpandPaneButtonInvoke;
	pane->panel = UIPanelCreate(parent, UI_ELEMENT_NON_CLIENT | panelFlags);
	return pane;
}

void _UIImageDisplayUpdateViewport(UIImageDisplay *display) {
	UIRectangle bounds = display->e.bounds;
	bounds.r -= bounds.l, bounds.b -= bounds.t;
	
	float minimumZoomX = 1, minimumZoomY = 1;
	if (display->width  > bounds.r) minimumZoomX = (float) bounds.r / display->width;
	if (display->height > bounds.b) minimumZoomY = (float) bounds.b / display->height;
	float minimumZoom = minimumZoomX < minimumZoomY ? minimumZoomX : minimumZoomY;
	
	if (display->zoom < minimumZoom || (display->e.flags & _UI_IMAGE_DISPLAY_ZOOM_FIT)) {
		display->zoom = minimumZoom;
		display->e.flags |= _UI_IMAGE_DISPLAY_ZOOM_FIT;
	}
	
	if (display->panX < 0) display->panX = 0;
	if (display->panY < 0) display->panY = 0;
	if (display->panX > display->width  - bounds.r / display->zoom) display->panX = display->width  - bounds.r / display->zoom;
	if (display->panY > display->height - bounds.b / display->zoom) display->panY = display->height - bounds.b / display->zoom;
	
	if (bounds.r && display->width  * display->zoom <= bounds.r) display->panX = display->width  / 2 - bounds.r / display->zoom / 2;
	if (bounds.b && display->height * display->zoom <= bounds.b) display->panY = display->height / 2 - bounds.b / display->zoom / 2;
}

int _UIImageDisplayMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UIImageDisplay *display = (UIImageDisplay *) element;
	
	if (message == UI_MSG_GET_HEIGHT) {
		return display->height;
	} else if (message == UI_MSG_GET_WIDTH) {
		return display->width;
	} else if (message == UI_MSG_DESTROY) {
		UI_FREE(display->bits);
	} else if (message == UI_MSG_PAINT) {
		UIPainter *painter = (UIPainter *) dp;
		
		int w = UI_RECT_WIDTH(element->bounds), h = UI_RECT_HEIGHT(element->bounds);
		int x = _UILinearMap(0, display->panX, display->panX + w / display->zoom, 0, w) + element->bounds.l;
		int y = _UILinearMap(0, display->panY, display->panY + h / display->zoom, 0, h) + element->bounds.t;
		
		UIRectangle image = UI_RECT_4(x, x + (int) (display->width * display->zoom), y, (int) (y + display->height * display->zoom));
		UIRectangle bounds = UIRectangleIntersection(painter->clip, UIRectangleIntersection(display->e.bounds, image));
		if (!UI_RECT_VALID(bounds)) return 0;
		
		if (display->zoom == 1) {
			uint32_t *lineStart = (uint32_t *) painter->bits + bounds.t * painter->width + bounds.l;
			uint32_t *sourceLineStart = display->bits + (bounds.l - image.l) + display->width * (bounds.t - image.t);
	
			for (int i = 0; i < bounds.b - bounds.t; i++, lineStart += painter->width, sourceLineStart += display->width) {
				uint32_t *destination = lineStart;
				uint32_t *source = sourceLineStart;
				int j = bounds.r - bounds.l;
	
				do {
					*destination = *source;
					destination++;
					source++;
				} while (--j);
			}
		} else {
			float zr = 1.0f / display->zoom;
			uint32_t *destination = (uint32_t *) painter->bits;
			
			for (int i = bounds.t; i < bounds.b; i++) {
				int ty = (i - image.t) * zr;
				
				for (int j = bounds.l; j < bounds.r; j++) {
					int tx = (j - image.l) * zr;
					destination[i * painter->width + j] = display->bits[ty * display->width + tx];
				}
			}
		}
	} else if (message == UI_MSG_MOUSE_WHEEL && (element->flags & UI_IMAGE_DISPLAY_INTERACTIVE)) {
		display->e.flags &= ~_UI_IMAGE_DISPLAY_ZOOM_FIT;
		int divisions = -di / 72;
		float factor = 1;
		float perDivision = element->window->ctrl ? 2.0f : element->window->alt ? 1.01f : 1.2f;
		while (divisions > 0) factor *= perDivision, divisions--;
		while (divisions < 0) factor /= perDivision, divisions++;
		if (display->zoom * factor > 64) factor = 64 / display->zoom;
		int mx = element->window->cursorX - element->bounds.l;
		int my = element->window->cursorY - element->bounds.t;
		display->zoom *= factor;
		display->panX -= mx / display->zoom * (1 - factor);
		display->panY -= my / display->zoom * (1 - factor);
		_UIImageDisplayUpdateViewport(display);
		UIElementRepaint(&display->e, NULL);
	} else if (message == UI_MSG_LAYOUT && (element->flags & UI_IMAGE_DISPLAY_INTERACTIVE)) {
		UIRectangle bounds = display->e.bounds;
		bounds.r -= bounds.l, bounds.b -= bounds.t;
		display->panX -= (bounds.r - display->previousWidth ) / 2 / display->zoom;
		display->panY -= (bounds.b - display->previousHeight) / 2 / display->zoom;
		display->previousWidth = bounds.r, display->previousHeight = bounds.b;
		_UIImageDisplayUpdateViewport(display);
	} else if (message == UI_MSG_GET_CURSOR && (element->flags & UI_IMAGE_DISPLAY_INTERACTIVE)
			&& (UI_RECT_WIDTH(element->bounds) < display->width * display->zoom 
				|| UI_RECT_HEIGHT(element->bounds) < display->height * display->zoom)) {
		return UI_CURSOR_HAND;
	} else if (message == UI_MSG_MOUSE_DRAG) {
		display->panX -= (element->window->cursorX - display->previousPanPointX) / display->zoom;
		display->panY -= (element->window->cursorY - display->previousPanPointY) / display->zoom;
		_UIImageDisplayUpdateViewport(display);
		display->previousPanPointX = element->window->cursorX;
		display->previousPanPointY = element->window->cursorY;
		UIElementRepaint(element, NULL);
	} else if (message == UI_MSG_LEFT_DOWN) {           
		display->e.flags &= ~_UI_IMAGE_DISPLAY_ZOOM_FIT;  
		display->previousPanPointX = element->window->cursorX;
		display->previousPanPointY = element->window->cursorY;
	}

	return 0;
}

void UIImageDisplaySetContent(UIImageDisplay *display, uint32_t *bits, size_t width, size_t height, size_t stride) {
	UI_FREE(display->bits);

	display->bits = (uint32_t *) UI_MALLOC(width * height * 4);
	display->width = width;
	display->height = height;

	uint32_t *destination = display->bits;
	uint32_t *source = bits;

	for (uintptr_t row = 0; row < height; row++, source += stride / 4) {
		for (uintptr_t i = 0; i < width; i++) {
			*destination++ = source[i];
		}
	}
}

UIImageDisplay *UIImageDisplayCreate(UIElement *parent, uint32_t flags, uint32_t *bits, size_t width, size_t height, size_t stride) {
	UIImageDisplay *display = (UIImageDisplay *) UIElementCreate(sizeof(UIImageDisplay), parent, flags, _UIImageDisplayMessage, "ImageDisplay");
	display->zoom = 1.0f;
	UIImageDisplaySetContent(display, bits, width, height, stride);
	return display;
}

int _UIDialogWrapperMessage(UIElement *element, UIMessage message, int di, void *dp) {
	if (message == UI_MSG_LAYOUT) {
		int width = UIElementMessage(element->children, UI_MSG_GET_WIDTH, 0, 0);
		int height = UIElementMessage(element->children, UI_MSG_GET_HEIGHT, width, 0);
		int cx = (element->bounds.l + element->bounds.r) / 2;
		int cy = (element->bounds.t + element->bounds.b) / 2;
		UIRectangle bounds = UI_RECT_4(cx - (width + 1) / 2, cx + width / 2, cy - (height + 1) / 2, cy + height / 2);
		UIElementMove(element->children, bounds, false);
		UIElementRepaint(element, NULL);
	} else if (message == UI_MSG_PAINT) {
		UIRectangle bounds = UIRectangleAdd(element->children->bounds, UI_RECT_1I(-1));
		UIDrawBorder((UIPainter *) dp, bounds, ui.theme.border, UI_RECT_1(1));
		UIDrawBorder((UIPainter *) dp, UIRectangleAdd(bounds, UI_RECT_1(1)), ui.theme.border, UI_RECT_1(1));
	} else if (message == UI_MSG_KEY_TYPED) {
		UIKeyTyped *typed = (UIKeyTyped *) dp;

		if (element->window->ctrl) return 0;
		if (element->window->shift) return 0;

		char c0 = 0, c1 = 0;

		if (typed->textBytes == 1 && typed->text[0] >= 'a' && typed->text[0] <= 'z') {
			c0 = typed->text[0], c1 = typed->text[0] - 'a' + 'A';
		} else {
			return 0;
		}

		UIElement *row = element->children->children;
		UIElement *target = NULL;
		bool duplicate = false;

		while (row) {
			UIElement *item = row->children;

			while (item) {
				if (item->messageClass == _UIButtonMessage) {
					UIButton *button = (UIButton *) item;

					if (button->label && button->labelBytes && (button->label[0] == c0 || button->label[0] == c1)) {
						if (!target) {
							target = &button->e;
						} else {
							duplicate = true;
						}
					}
				}

				item = item->next;
			}

			row = row->next;
		}

		if (target) {
			if (duplicate) {
				UIElementFocus(target);
			} else {
				UIElementMessage(target, UI_MSG_CLICKED, 0, 0);
			}

			return 1;
		}
	}

	return 0;
}

void _UIDialogButtonInvoke(void *cp) {
	ui.dialogResult = (const char *) cp;
}

int _UIDialogTextboxMessage(UIElement *element, UIMessage message, int di, void *dp) {
	if (message == UI_MSG_VALUE_CHANGED) {
		UITextbox *textbox = (UITextbox *) element;
		char **buffer = (char **) element->cp;
		*buffer = (char *) UI_REALLOC(*buffer, textbox->bytes + 1);
		(*buffer)[textbox->bytes] = 0;

		for (ptrdiff_t i = 0; i < textbox->bytes; i++) {
			(*buffer)[i] = textbox->string[i];
		}
	}

	return 0;
}

const char *UIDialogShow(UIWindow *window, uint32_t flags, const char *format, ...) {
	// TODO Enter and escape.

	// Create the dialog wrapper and panel.

	UI_ASSERT(!window->dialog);
	window->dialog = UIElementCreate(sizeof(UIElement), &window->e, 0, _UIDialogWrapperMessage, "DialogWrapper");
	UIPanel *panel = UIPanelCreate(window->dialog, UI_PANEL_MEDIUM_SPACING | UI_PANEL_GRAY | UI_PANEL_EXPAND);
	panel->border = UI_RECT_1(UI_SIZE_PANE_MEDIUM_BORDER * 2);
	window->e.children->flags |= UI_ELEMENT_DISABLED;

	// Create the dialog contents.

	va_list arguments;
	va_start(arguments, format);
	UIPanel *row = NULL;
	UIElement *focus = NULL;

	for (int i = 0; format[i]; i++) {
		if (i == 0 || format[i - 1] == '\n') {
			row = UIPanelCreate(&panel->e, UI_PANEL_HORIZONTAL);
			row->gap = UI_SIZE_PANE_SMALL_GAP;
		}

		if (format[i] == ' ' || format[i] == '\n') {
		} else if (format[i] == '%') {
			i++;

			if (format[i] == 'b' /* button */) {
				const char *label = va_arg(arguments, const char *);
				UIButton *button = UIButtonCreate(&row->e, 0, label, -1);
				if (!focus) focus = &button->e;
				button->invoke = _UIDialogButtonInvoke;
				button->e.cp = (void *) label;
			} else if (format[i] == 's' /* label from string */) {
				const char *label = va_arg(arguments, const char *);
				UILabelCreate(&row->e, 0, label, -1);
			} else if (format[i] == 't' /* textbox */) {
				char **buffer = va_arg(arguments, char **);
				UITextbox *textbox = UITextboxCreate(&row->e, UI_ELEMENT_H_FILL);
				if (!focus) focus = &textbox->e;
				if (*buffer) UITextboxReplace(textbox, *buffer, _UIStringLength(*buffer), false);
				textbox->e.cp = buffer;
				textbox->e.messageUser = _UIDialogTextboxMessage;
			} else if (format[i] == 'f' /* horizontal fill */) {
				UISpacerCreate(&row->e, UI_ELEMENT_H_FILL, 0, 0);
			} else if (format[i] == 'l' /* horizontal line */) {
				UISpacerCreate(&row->e, UI_SPACER_LINE | UI_ELEMENT_H_FILL, 0, 1);
			} else if (format[i] == 'u' /* user */) {
				void (*callback)(UIElement *) = va_arg(arguments, void (*)(UIElement *));
				callback(&row->e);
			}
		} else {
			int j = i;
			while (format[j] && format[j] != '%' && format[j] != '\n') j++;
			UILabelCreate(&row->e, 0, format + i, j - i);
			i = j - 1;
		}
	}

	va_end(arguments);

	window->dialogOldFocus = window->focused;
	UIElementFocus(focus ? focus : window->dialog);

	// Run the modal message loop.

	int result;
	ui.dialogResult = NULL;
	for (int i = 1; i <= 3; i++) _UIWindowSetPressed(window, NULL, i);
	UIElementRefresh(&window->e);
	_UIUpdate();
	while (!ui.dialogResult && _UIMessageLoopSingle(&result));
	ui.quit = !ui.dialogResult;

	// Destroy the dialog.

	window->e.children->flags &= ~UI_ELEMENT_DISABLED;
	UIElementDestroy(window->dialog);
	window->dialog = NULL;
	UIElementRefresh(&window->e);
	if (window->dialogOldFocus) UIElementFocus(window->dialogOldFocus);
	return ui.dialogResult ? ui.dialogResult : "";
}

bool _UIMenusClose() {
	UIWindow *window = ui.windows;
	bool anyClosed = false;

	while (window) {
		if (window->e.flags & UI_WINDOW_MENU) {
			UIElementDestroy(&window->e);
			anyClosed = true;
		}

		window = window->next;
	}

	return anyClosed;
}

#ifndef UI_ESSENCE
int _UIMenuItemMessage(UIElement *element, UIMessage message, int di, void *dp) {
	if (message == UI_MSG_CLICKED) {
		_UIMenusClose();
	}

	return 0;
}

int _UIMenuMessage(UIElement *element, UIMessage message, int di, void *dp) {
	UIMenu *menu = (UIMenu *) element;

	if (message == UI_MSG_GET_WIDTH) {
		UIElement *child = element->children;
		int width = 0;

		while (child) {
			if (~child->flags & UI_ELEMENT_NON_CLIENT) {
				int w = UIElementMessage(child, UI_MSG_GET_WIDTH, 0, 0);
				if (w > width) width = w;
			}

			child = child->next;
		}

		return width + 4 + UI_SIZE_SCROLL_BAR;
	} else if (message == UI_MSG_GET_HEIGHT) {
		UIElement *child = element->children;
		int height = 0;

		while (child) {
			if (~child->flags & UI_ELEMENT_NON_CLIENT) {
				height += UIElementMessage(child, UI_MSG_GET_HEIGHT, 0, 0);
			}

			child = child->next;
		}

		return height + 4;
	} else if (message == UI_MSG_PAINT) {
		UIDrawBlock((UIPainter *) dp, element->bounds, ui.theme.border);
	} else if (message == UI_MSG_LAYOUT) {
		UIElement *child = element->children;
		int position = element->bounds.t + 2 - menu->vScroll->position;
		int totalHeight = 0;
		int scrollBarSize = (menu->e.flags & UI_MENU_NO_SCROLL) ? 0 : UI_SIZE_SCROLL_BAR;

		while (child) {
			if (~child->flags & UI_ELEMENT_NON_CLIENT) {
				int height = UIElementMessage(child, UI_MSG_GET_HEIGHT, 0, 0);
				UIElementMove(child, UI_RECT_4(element->bounds.l + 2, element->bounds.r - scrollBarSize - 2, 
							position, position + height), false);
				position += height;
				totalHeight += height;
			}

			child = child->next;
		}

		UIRectangle scrollBarBounds = element->bounds;
		scrollBarBounds.l = scrollBarBounds.r - scrollBarSize * element->window->scale;
		menu->vScroll->maximum = totalHeight;
		menu->vScroll->page = UI_RECT_HEIGHT(element->bounds);
		UIElementMove(&menu->vScroll->e, scrollBarBounds, true);
	} else if (message == UI_MSG_KEY_TYPED) {
		UIKeyTyped *m = (UIKeyTyped *) dp;

		if (m->code == UI_KEYCODE_ESCAPE) {
			_UIMenusClose();
			return 1;
		}
	} else if (message == UI_MSG_MOUSE_WHEEL) {
		return UIElementMessage(&menu->vScroll->e, message, di, dp);
	} else if (message == UI_MSG_SCROLLED) {
		UIElementRefresh(element);
	}

	return 0;
}

void UIMenuAddItem(UIMenu *menu, uint32_t flags, const char *label, ptrdiff_t labelBytes, void (*invoke)(void *cp), void *cp) {
	UIButton *button = UIButtonCreate(&menu->e, flags | UI_BUTTON_MENU_ITEM, label, labelBytes);
	button->invoke = invoke;
	button->e.messageUser = _UIMenuItemMessage;
	button->e.cp = cp;
}

void _UIMenuPrepare(UIMenu *menu, int *width, int *height) {
	*width = UIElementMessage(&menu->e, UI_MSG_GET_WIDTH, 0, 0);
	*height = UIElementMessage(&menu->e, UI_MSG_GET_HEIGHT, 0, 0);

	if (menu->e.flags & UI_MENU_PLACE_ABOVE) {
		menu->pointY -= *height;
	}
}

UIMenu *UIMenuCreate(UIElement *parent, uint32_t flags) {
	UIWindow *window = UIWindowCreate(parent->window, UI_WINDOW_MENU, 0, 0, 0);
	UIMenu *menu = (UIMenu *) UIElementCreate(sizeof(UIMenu), &window->e, flags, _UIMenuMessage, "Menu");
	menu->vScroll = UIScrollBarCreate(&menu->e, UI_ELEMENT_NON_CLIENT);

	if (parent->parent) {
		UIRectangle screenBounds = UIElementScreenBounds(parent);
		menu->pointX = screenBounds.l;
		menu->pointY = (flags & UI_MENU_PLACE_ABOVE) ? (screenBounds.t + 1) : (screenBounds.b - 1);
	} else {
		int x = 0, y = 0;
		_UIWindowGetScreenPosition(parent->window, &x, &y);

		menu->pointX = parent->window->cursorX + x;
		menu->pointY = parent->window->cursorY + y;
	}

	return menu;
}
#endif

UIRectangle UIElementScreenBounds(UIElement *element) {
	int x = 0, y = 0;
	_UIWindowGetScreenPosition(element->window, &x, &y);
	return UIRectangleAdd(element->bounds, UI_RECT_2(x, y));
}

void UIWindowRegisterShortcut(UIWindow *window, UIShortcut shortcut) {
	if (window->shortcutCount + 1 > window->shortcutAllocated) {
		window->shortcutAllocated = (window->shortcutCount + 1) * 2;
		window->shortcuts = (UIShortcut *) UI_REALLOC(window->shortcuts, window->shortcutAllocated * sizeof(UIShortcut));
	}

	window->shortcuts[window->shortcutCount++] = shortcut;
}

void _UIElementPaint(UIElement *element, UIPainter *painter) {
	if (element->flags & UI_ELEMENT_HIDE) {
		return;
	}

	// Clip painting to the element's clip.

	painter->clip = UIRectangleIntersection(element->clip, painter->clip);

	if (!UI_RECT_VALID(painter->clip)) {
		return;
	}

	// Paint the element.

	UIElementMessage(element, UI_MSG_PAINT, 0, painter);

	// Paint its children.

	UIElement *child = element->children;
	UIRectangle previousClip = painter->clip;

	while (child) {
		painter->clip = previousClip;
		_UIElementPaint(child, painter);
		child = child->next;
	}
}

void UIElementFocus(UIElement *element) {
	UIElement *previous = element->window->focused;
	if (previous == element) return;
	element->window->focused = element;
	if (previous) UIElementMessage(previous, UI_MSG_UPDATE, UI_UPDATE_FOCUSED, 0);
	if (element) UIElementMessage(element, UI_MSG_UPDATE, UI_UPDATE_FOCUSED, 0);

#ifdef UI_DEBUG
	_UIInspectorRefresh();
#endif
}

void _UIWindowSetPressed(UIWindow *window, UIElement *element, int button) {
	UIElement *previous = window->pressed;
	window->pressed = element;
	window->pressedButton = button;
	if (previous) UIElementMessage(previous, UI_MSG_UPDATE, UI_UPDATE_PRESSED, 0);
	if (element) UIElementMessage(element, UI_MSG_UPDATE, UI_UPDATE_PRESSED, 0);

	UIElement *ancestor = element;
	UIElement *child = NULL;

	while (ancestor) {
		UIElementMessage(ancestor, UI_MSG_PRESSED_DESCENDENT, 0, child);
		child = ancestor;
		ancestor = ancestor->parent;
	}
}

bool _UIDestroy(UIElement *element) {
	if (element->flags & UI_ELEMENT_DESTROY_DESCENDENT) {
		element->flags &= ~UI_ELEMENT_DESTROY_DESCENDENT;

		UIElement *child = element->children;
		UIElement **link = &element->children;

		while (child) {
			UIElement *next = child->next;

			if (_UIDestroy(child)) {
				*link = next;
			} else {
				link = &child->next;
			}

			child = next;
		}
	}

	if (element->flags & UI_ELEMENT_DESTROY) {
		UIElementMessage(element, UI_MSG_DESTROY, 0, 0);

		if (element->window->pressed == element) {
			_UIWindowSetPressed(element->window, NULL, 0);
		}

		if (element->window->hovered == element) {
			element->window->hovered = &element->window->e;
		}

		if (element->window->focused == element) {
			element->window->focused = NULL;
		}

		if (element->window->dialogOldFocus == element) {
			element->window->dialogOldFocus = NULL;
		}

		if (ui.animating == element) {
			ui.animating = NULL;
		}

		UI_FREE(element);
		return true;
	} else {
		return false;
	}
}

void _UIUpdate() {
	UIWindow *window = ui.windows;
	UIWindow **link = &ui.windows;

	while (window) {
		UIWindow *next = window->next;

		if (_UIDestroy(&window->e)) {
			*link = next;
		} else {
			link = &window->next;

			if (UI_RECT_VALID(window->updateRegion)) {
#ifdef __cplusplus
				UIPainter painter = {};
#else
				UIPainter painter = { 0 };
#endif
				painter.bits = window->bits;
				painter.width = window->width;
				painter.height = window->height;
				painter.clip = UIRectangleIntersection(UI_RECT_2S(window->width, window->height), window->updateRegion);
				_UIElementPaint(&window->e, &painter);
				_UIWindowEndPaint(window, &painter);
				window->updateRegion = UI_RECT_1(0);

#ifdef UI_DEBUG
				window->lastFullFillCount = (float) painter.fillCount / (UI_RECT_WIDTH(window->updateRegion) * UI_RECT_HEIGHT(window->updateRegion));
#endif
			}
		}

		window = next;
	}
}

UIElement *UIElementFindByPoint(UIElement *element, int x, int y) {
	UIFindByPoint m = { 0 };
	m.x = x, m.y = y;

	if (UIElementMessage(element, UI_MSG_FIND_BY_POINT, 0, &m)) {
		return m.result ? m.result : element;
	}

	UIElement *child = element->children;

	while (child) {
		if ((~child->flags & UI_ELEMENT_HIDE) && UIRectangleContains(child->clip, x, y)) {
			return UIElementFindByPoint(child, x, y);
		}

		child = child->next;
	}

	return element;
}

void _UIProcessAnimations() {
	if (ui.animating) {
		UIElementMessage(ui.animating, UI_MSG_ANIMATE, 0, 0);
		_UIUpdate();
	}
}

bool _UIMenusOpen() {
	UIWindow *window = ui.windows;

	while (window) {
		if (window->e.flags & UI_WINDOW_MENU) {
			return true;
		}

		window = window->next;
	}

	return false;
}

void _UIWindowDestroyCommon(UIWindow *window) {
	UI_FREE(window->bits);
	UI_FREE(window->shortcuts);
}

UIElement *_UIElementLastChild(UIElement *element) {
	if (!element->children) {
		return NULL;
	}

	UIElement *child = element->children;

	while (child->next) {
		child = child->next;
	}

	return child;
}

UIElement *_UIElementPreviousSibling(UIElement *element) {
	if (!element->parent) {
		return NULL;
	}

	UIElement *sibling = element->parent->children;

	if (sibling == element) {
		return NULL;
	}

	while (sibling->next != element) {
		sibling = sibling->next;
		UI_ASSERT(sibling);
	}
	
	return sibling;
}

bool _UIWindowInputEvent(UIWindow *window, UIMessage message, int di, void *dp) {
	bool handled = true;

	if (window->pressed) {
		if (message == UI_MSG_MOUSE_MOVE) {
			UIElementMessage(window->pressed, UI_MSG_MOUSE_DRAG, di, dp);
		} else if (message == UI_MSG_LEFT_UP && window->pressedButton == 1) {
			if (window->hovered == window->pressed) {
				UIElementMessage(window->pressed, UI_MSG_CLICKED, di, dp);
				if (ui.quit || ui.dialogResult) goto end;
			}

			if (window->pressed) {
				UIElementMessage(window->pressed, UI_MSG_LEFT_UP, di, dp);
				if (ui.quit || ui.dialogResult) goto end;
				_UIWindowSetPressed(window, NULL, 1);
			}
		} else if (message == UI_MSG_MIDDLE_UP && window->pressedButton == 2) {
			UIElementMessage(window->pressed, UI_MSG_MIDDLE_UP, di, dp);
			if (ui.quit || ui.dialogResult) goto end;
			_UIWindowSetPressed(window, NULL, 2);
		} else if (message == UI_MSG_RIGHT_UP && window->pressedButton == 3) {
			UIElementMessage(window->pressed, UI_MSG_RIGHT_UP, di, dp);
			if (ui.quit || ui.dialogResult) goto end;
			_UIWindowSetPressed(window, NULL, 3);
		}
	}

	if (window->pressed) {
		bool inside = UIRectangleContains(window->pressed->clip, window->cursorX, window->cursorY);

		if (inside && window->hovered == &window->e) {
			window->hovered = window->pressed;
			UIElementMessage(window->pressed, UI_MSG_UPDATE, UI_UPDATE_HOVERED, 0);
		} else if (!inside && window->hovered == window->pressed) {
			window->hovered = &window->e;
			UIElementMessage(window->pressed, UI_MSG_UPDATE, UI_UPDATE_HOVERED, 0);
		}

		if (ui.quit || ui.dialogResult) goto end;
	}

	if (!window->pressed) {
		UIElement *hovered = UIElementFindByPoint(&window->e, window->cursorX, window->cursorY);

		if (message == UI_MSG_MOUSE_MOVE) {
			UIElementMessage(hovered, UI_MSG_MOUSE_MOVE, di, dp);

			int cursor = UIElementMessage(window->hovered, UI_MSG_GET_CURSOR, di, dp);

			if (cursor != window->cursorStyle) {
				window->cursorStyle = cursor;
				_UIWindowSetCursor(window, cursor);
			}
		} else if (message == UI_MSG_LEFT_DOWN) {
			if ((window->e.flags & UI_WINDOW_MENU) || !_UIMenusClose()) {
				_UIWindowSetPressed(window, hovered, 1);
				UIElementMessage(hovered, UI_MSG_LEFT_DOWN, di, dp);
			}
		} else if (message == UI_MSG_MIDDLE_DOWN) {
			if ((window->e.flags & UI_WINDOW_MENU) || !_UIMenusClose()) {
				_UIWindowSetPressed(window, hovered, 2);
				UIElementMessage(hovered, UI_MSG_MIDDLE_DOWN, di, dp);
			}
		} else if (message == UI_MSG_RIGHT_DOWN) {
			if ((window->e.flags & UI_WINDOW_MENU) || !_UIMenusClose()) {
				_UIWindowSetPressed(window, hovered, 3);
				UIElementMessage(hovered, UI_MSG_RIGHT_DOWN, di, dp);
			}
		} else if (message == UI_MSG_MOUSE_WHEEL) {
			UIElement *element = hovered;

			while (element) {
				if (UIElementMessage(element, UI_MSG_MOUSE_WHEEL, di, dp)) {
					break;
				}

				element = element->parent;
			}
		} else if (message == UI_MSG_KEY_TYPED) {
			handled = false;

			if (window->focused) {
				UIElement *element = window->focused;

				while (element) {
					if (UIElementMessage(element, UI_MSG_KEY_TYPED, di, dp)) {
						handled = true;
						break;
					}

					element = element->parent;
				}
			} else {
				if (UIElementMessage(&window->e, UI_MSG_KEY_TYPED, di, dp)) {
					handled = true;
				}
			}

			if (!handled && !_UIMenusOpen()) {
				UIKeyTyped *m = (UIKeyTyped *) dp;

				if (m->code == UI_KEYCODE_TAB && !window->ctrl && !window->alt) {
					UIElement *start = window->focused ? window->focused : &window->e;
					UIElement *element = start;

					do {
						if (element->children && !(element->flags & (UI_ELEMENT_HIDE | UI_ELEMENT_DISABLED))) {
							element = window->shift ? _UIElementLastChild(element) : element->children;
							continue;
						} 

						while (element) {
							if (window->shift ? (element->parent && element->parent->children != element) : !!element->next) {
								element = window->shift ? _UIElementPreviousSibling(element) : element->next;
								break;
							} else {
								element = element->parent;
							}
						}

						if (!element) {
							element = &window->e;
						}
					} while (element != start && ((~element->flags & UI_ELEMENT_TAB_STOP) 
						|| (element->flags & (UI_ELEMENT_HIDE | UI_ELEMENT_DISABLED))));

					if (~element->flags & UI_ELEMENT_WINDOW) {
						UIElementFocus(element);
					}

					handled = true;
				} else if (!window->dialog) {
					for (intptr_t i = window->shortcutCount - 1; i >= 0; i--) {
						UIShortcut *shortcut = window->shortcuts + i;

						if (shortcut->code == m->code && shortcut->ctrl == window->ctrl 
								&& shortcut->shift == window->shift && shortcut->alt == window->alt) {
							shortcut->invoke(shortcut->cp);
							handled = true;
							break;
						}
					}
				}
			}
		}

		if (ui.quit || ui.dialogResult) goto end;

		if (hovered != window->hovered) {
			UIElement *previous = window->hovered;
			window->hovered = hovered;
			UIElementMessage(previous, UI_MSG_UPDATE, UI_UPDATE_HOVERED, 0);
			UIElementMessage(window->hovered, UI_MSG_UPDATE, UI_UPDATE_HOVERED, 0);
		}
	}

	end: _UIUpdate();
	return handled;
}

UIFont *UIFontCreate(const char *cPath, uint32_t size) {
	UIFont *font = (UIFont *) UI_CALLOC(sizeof(UIFont));

#ifdef UI_FREETYPE
	if (cPath) {
		if (!FT_New_Face(ui.ft, cPath, 0, &font->font)) {
			FT_Set_Char_Size(font->font, 0, size * 64, 100, 100);
			FT_Load_Char(font->font, 'a', FT_LOAD_DEFAULT);
			font->glyphWidth = font->font->glyph->advance.x / 64;
			font->glyphHeight = (font->font->size->metrics.ascender - font->font->size->metrics.descender) / 64;
			font->isFreeType = true;
			return font;
		}
	}
#endif
	
	font->glyphWidth = 9;
	font->glyphHeight = 16;
	return font;
}

UIFont *UIFontActivate(UIFont *font) {
	UIFont *previous = ui.activeFont;
	ui.activeFont = font;
	return previous;
}

void _UIInitialiseCommon() {
	ui.theme = _uiThemeDark;

#ifdef UI_FREETYPE
	FT_Init_FreeType(&ui.ft);
	UIFontActivate(UIFontCreate(_UI_TO_STRING_2(UI_FONT_PATH), 11));
#else
	UIFontActivate(UIFontCreate(0, 0));
#endif
}

void _UIWindowAdd(UIWindow *window) {
	window->scale = 1.0f;
	window->e.window = window;
	window->hovered = &window->e;
	window->next = ui.windows;
	ui.windows = window;
}

int _UIWindowMessageCommon(UIElement *element, UIMessage message, int di, void *dp) {
	if (message == UI_MSG_LAYOUT && element->children) {
		UIElementMove(element->children, element->bounds, false);
		if (element->window->dialog) UIElementMove(element->window->dialog, element->bounds, false);
		UIElementRepaint(element, NULL);
	} else if (message == UI_MSG_FIND_BY_POINT) {
		UIFindByPoint *m = (UIFindByPoint *) dp;
		if (element->window->dialog) m->result = UIElementFindByPoint(element->window->dialog, m->x, m->y);
		else if (!element->children) m->result = NULL;
		else m->result = UIElementFindByPoint(element->children, m->x, m->y);
		return 1;
	}

	return 0;
}

#ifdef UI_DEBUG

void UIInspectorLog(const char *cFormat, ...) {
	va_list arguments;
	va_start(arguments, cFormat);
	char buffer[4096];
	vsnprintf(buffer, sizeof(buffer), cFormat, arguments);
	UICodeInsertContent(ui.inspectorLog, buffer, -1, false);
	va_end(arguments);
	UIElementRefresh(&ui.inspectorLog->e);
}

UIElement *_UIInspectorFindNthElement(UIElement *element, int *index, int *depth) {
	if (*index == 0) {
		return element;
	}

	*index = *index - 1;
	
	UIElement *child = element->children;

	while (child) {
		if (!(child->flags & (UI_ELEMENT_DESTROY | UI_ELEMENT_HIDE))) {
			UIElement *result = _UIInspectorFindNthElement(child, index, depth);

			if (result) {
				if (depth) {
					*depth = *depth + 1;
				}

				return result;
			}
		}

		child = child->next;
	}

	return NULL;
}

int _UIInspectorTableMessage(UIElement *element, UIMessage message, int di, void *dp) {
	if (!ui.inspectorTarget) {
		return 0;
	}

	if (message == UI_MSG_TABLE_GET_ITEM) {
		UITableGetItem *m = (UITableGetItem *) dp;
		int index = m->index;
		int depth = 0;
		UIElement *element = _UIInspectorFindNthElement(&ui.inspectorTarget->e, &index, &depth);
		if (!element) return 0;

		if (m->column == 0) {
			return snprintf(m->buffer, m->bufferBytes, "%.*s%s", depth * 2, "                ", element->cClassName);
		} else if (m->column == 1) {
			return snprintf(m->buffer, m->bufferBytes, "%d:%d, %d:%d", UI_RECT_ALL(element->bounds));
		} else if (m->column == 2) {
			return snprintf(m->buffer, m->bufferBytes, "%d%c", element->id, element->window->focused == element ? '*' : ' ');
		}
	} else if (message == UI_MSG_MOUSE_MOVE) {
		int index = UITableHitTest(ui.inspectorTable, element->window->cursorX, element->window->cursorY);
		UIElement *element = NULL;
		if (index >= 0) element = _UIInspectorFindNthElement(&ui.inspectorTarget->e, &index, NULL);
		UIWindow *window = ui.inspectorTarget;
		UIPainter painter = { 0 };
		window->updateRegion = window->e.bounds;
		painter.bits = window->bits;
		painter.width = window->width;
		painter.height = window->height;
		painter.clip = UI_RECT_2S(window->width, window->height);

		for (int i = 0; i < window->width * window->height; i++) {
			window->bits[i] = 0xFF00FF;
		}

		_UIElementPaint(&window->e, &painter);
		painter.clip = UI_RECT_2S(window->width, window->height);

		if (element) {
			UIDrawInvert(&painter, element->bounds);
			UIDrawInvert(&painter, UIRectangleAdd(element->bounds, UI_RECT_1I(4)));
		}

		_UIWindowEndPaint(window, &painter);
	}

	return 0;
}

void _UIInspectorCreate() {
	ui.inspector = UIWindowCreate(0, UI_WINDOW_INSPECTOR, "Inspector", 0, 0);
	UISplitPane *splitPane = UISplitPaneCreate(&ui.inspector->e, 0, 0.5f);
	ui.inspectorTable = UITableCreate(&splitPane->e, 0, "Class\tBounds\tID");
	ui.inspectorTable->e.messageUser = _UIInspectorTableMessage;
	ui.inspectorLog = UICodeCreate(&splitPane->e, 0);
}

int _UIInspectorCountElements(UIElement *element) {
	UIElement *child = element->children;
	int count = 1;

	while (child) {
		if (!(child->flags & (UI_ELEMENT_DESTROY | UI_ELEMENT_HIDE))) {
			count += _UIInspectorCountElements(child);
		}

		child = child->next;
	}

	return count;
}

void _UIInspectorRefresh() {
	if (!ui.inspectorTarget || !ui.inspector || !ui.inspectorTable) return;
	ui.inspectorTable->itemCount = _UIInspectorCountElements(&ui.inspectorTarget->e);
	UITableResizeColumns(ui.inspectorTable);
	UIElementRefresh(&ui.inspectorTable->e);
}

void _UIInspectorSetFocusedWindow(UIWindow *window) {
	if (!ui.inspector || !ui.inspectorTable) return;

	if (window->e.flags & UI_WINDOW_INSPECTOR) {
		return;
	}

	if (ui.inspectorTarget != window) {
		ui.inspectorTarget = window;
		_UIInspectorRefresh();
	}
}

#else

void _UIInspectorCreate() {}
void _UIInspectorSetFocusedWindow(UIWindow *window) {}
void _UIInspectorRefresh() {}

#endif

int UIMessageLoop() {
	_UIInspectorCreate();
	_UIUpdate();
	int result = 0;
	while (!ui.quit && _UIMessageLoopSingle(&result)) ui.dialogResult = NULL;
	return result;
}

#ifdef UI_LINUX

const int UI_KEYCODE_A = XK_a;
const int UI_KEYCODE_BACKSPACE = XK_BackSpace;
const int UI_KEYCODE_DELETE = XK_Delete;
const int UI_KEYCODE_DOWN = XK_Down;
const int UI_KEYCODE_END = XK_End;
const int UI_KEYCODE_ENTER = XK_Return;
const int UI_KEYCODE_ESCAPE = XK_Escape;
const int UI_KEYCODE_F1 = XK_F1;
const int UI_KEYCODE_HOME = XK_Home;
const int UI_KEYCODE_LEFT = XK_Left;
const int UI_KEYCODE_RIGHT = XK_Right;
const int UI_KEYCODE_SPACE = XK_space;
const int UI_KEYCODE_TAB = XK_Tab;
const int UI_KEYCODE_UP = XK_Up;
const int UI_KEYCODE_0 = XK_0;

int _UIWindowMessage(UIElement *element, UIMessage message, int di, void *dp) {
	if (message == UI_MSG_DESTROY) {
		UIWindow *window = (UIWindow *) element;
		_UIWindowDestroyCommon(window);
		window->image->data = NULL;
		XDestroyImage(window->image);
		XDestroyIC(window->xic);
		XDestroyWindow(ui.display, ((UIWindow *) element)->window);
	}

	return _UIWindowMessageCommon(element, message, di, dp);
}

UIWindow *UIWindowCreate(UIWindow *owner, uint32_t flags, const char *cTitle, int _width, int _height) {
	_UIMenusClose();

	UIWindow *window = (UIWindow *) UIElementCreate(sizeof(UIWindow), NULL, flags | UI_ELEMENT_WINDOW, _UIWindowMessage, "Window");
	_UIWindowAdd(window);
	if (owner) window->scale = owner->scale;

	int width = (flags & UI_WINDOW_MENU) ? 1 : _width ? _width : 800;
	int height = (flags & UI_WINDOW_MENU) ? 1 : _height ? _height : 600;

	XSetWindowAttributes attributes = {};
	attributes.override_redirect = flags & UI_WINDOW_MENU;

	window->window = XCreateWindow(ui.display, DefaultRootWindow(ui.display), 0, 0, width, height, 0, 0, 
		InputOutput, CopyFromParent, CWOverrideRedirect, &attributes);
	if (cTitle) XStoreName(ui.display, window->window, cTitle);
	XSelectInput(ui.display, window->window, SubstructureNotifyMask | ExposureMask | PointerMotionMask 
		| ButtonPressMask | ButtonReleaseMask | KeyPressMask | KeyReleaseMask | StructureNotifyMask
		| EnterWindowMask | LeaveWindowMask | ButtonMotionMask | KeymapStateMask | FocusChangeMask);

	if (flags & UI_WINDOW_MAXIMIZE) {
		Atom atoms[2] = { XInternAtom(ui.display, "_NET_WM_STATE_MAXIMIZED_HORZ", 0), XInternAtom(ui.display, "_NET_WM_STATE_MAXIMIZED_VERT", 0) };
		XChangeProperty(ui.display, window->window, XInternAtom(ui.display, "_NET_WM_STATE", 0), XA_ATOM, 32, PropModeReplace, (unsigned char *) atoms, 2);
	}

	if (~flags & UI_WINDOW_MENU) {
		XMapRaised(ui.display, window->window);
	}

	if (flags & UI_WINDOW_CENTER_IN_OWNER) {
		int x = 0, y = 0;
		_UIWindowGetScreenPosition(owner, &x, &y);
		XMoveResizeWindow(ui.display, window->window, x + owner->width / 2 - width / 2, y + owner->height / 2 - height / 2, width, height);
	}

	XSetWMProtocols(ui.display, window->window, &ui.windowClosedID, 1);
	window->image = XCreateImage(ui.display, ui.visual, 24, ZPixmap, 0, NULL, 10, 10, 32, 0);

	window->xic = XCreateIC(ui.xim, XNInputStyle, XIMPreeditNothing | XIMStatusNothing, XNClientWindow, window->window, XNFocusWindow, window->window, NULL);

	int dndVersion = 4;
	XChangeProperty(ui.display, window->window, ui.dndAwareID, XA_ATOM, 32 /* bits */, PropModeReplace, (uint8_t *) &dndVersion, 1);

	return window;
}

Display *_UIX11GetDisplay() {
	return ui.display;
}

void UIInitialise() {
	_UIInitialiseCommon();

	XInitThreads();

	ui.display = XOpenDisplay(NULL);
	ui.visual = XDefaultVisual(ui.display, 0);

	ui.windowClosedID = XInternAtom(ui.display, "WM_DELETE_WINDOW", 0);
	ui.primaryID = XInternAtom(ui.display, "PRIMARY", 0);
	ui.dndEnterID = XInternAtom(ui.display, "XdndEnter", 0);
	ui.dndPositionID = XInternAtom(ui.display, "XdndPosition", 0);
	ui.dndStatusID = XInternAtom(ui.display, "XdndStatus", 0);
	ui.dndActionCopyID = XInternAtom(ui.display, "XdndActionCopy", 0);
	ui.dndDropID = XInternAtom(ui.display, "XdndDrop", 0);
	ui.dndSelectionID = XInternAtom(ui.display, "XdndSelection", 0);
	ui.dndFinishedID = XInternAtom(ui.display, "XdndFinished", 0);
	ui.dndAwareID = XInternAtom(ui.display, "XdndAware", 0);
	ui.uriListID = XInternAtom(ui.display, "text/uri-list", 0);
	ui.plainTextID = XInternAtom(ui.display, "text/plain", 0);

	ui.cursors[UI_CURSOR_ARROW] = XCreateFontCursor(ui.display, XC_left_ptr);
	ui.cursors[UI_CURSOR_TEXT] = XCreateFontCursor(ui.display, XC_xterm);
	ui.cursors[UI_CURSOR_SPLIT_V] = XCreateFontCursor(ui.display, XC_sb_v_double_arrow);
	ui.cursors[UI_CURSOR_SPLIT_H] = XCreateFontCursor(ui.display, XC_sb_h_double_arrow);
	ui.cursors[UI_CURSOR_FLIPPED_ARROW] = XCreateFontCursor(ui.display, XC_right_ptr);
	ui.cursors[UI_CURSOR_CROSS_HAIR] = XCreateFontCursor(ui.display, XC_crosshair);
	ui.cursors[UI_CURSOR_HAND] = XCreateFontCursor(ui.display, XC_hand1);
	ui.cursors[UI_CURSOR_RESIZE_UP] = XCreateFontCursor(ui.display, XC_top_side);
	ui.cursors[UI_CURSOR_RESIZE_LEFT] = XCreateFontCursor(ui.display, XC_left_side);
	ui.cursors[UI_CURSOR_RESIZE_UP_RIGHT] = XCreateFontCursor(ui.display, XC_top_right_corner);
	ui.cursors[UI_CURSOR_RESIZE_UP_LEFT] = XCreateFontCursor(ui.display, XC_top_left_corner);
	ui.cursors[UI_CURSOR_RESIZE_DOWN] = XCreateFontCursor(ui.display, XC_bottom_side);
	ui.cursors[UI_CURSOR_RESIZE_RIGHT] = XCreateFontCursor(ui.display, XC_right_side);
	ui.cursors[UI_CURSOR_RESIZE_DOWN_LEFT] = XCreateFontCursor(ui.display, XC_bottom_left_corner);
	ui.cursors[UI_CURSOR_RESIZE_DOWN_RIGHT] = XCreateFontCursor(ui.display, XC_bottom_right_corner);

	XSetLocaleModifiers("");

	ui.xim = XOpenIM(ui.display, 0, 0, 0);

	if(!ui.xim){
		XSetLocaleModifiers("@im=none");
		ui.xim = XOpenIM(ui.display, 0, 0, 0);
	}
}

UIWindow *_UIFindWindow(Window window) {
	UIWindow *w = ui.windows;

	while (w) {
		if (w->window == window) {
			return w;
		}

		w = w->next;
	}

	return NULL;
}

void _UIWindowSetCursor(UIWindow *window, int cursor) {
	XDefineCursor(ui.display, window->window, ui.cursors[cursor]);
}

void _UIX11ResetCursor(UIWindow *window) {
	XDefineCursor(ui.display, window->window, ui.cursors[UI_CURSOR_ARROW]);
}

void _UIWindowEndPaint(UIWindow *window, UIPainter *painter) {
	(void) painter;

	XPutImage(ui.display, window->window, DefaultGC(ui.display, 0), window->image, 
		UI_RECT_TOP_LEFT(window->updateRegion), UI_RECT_TOP_LEFT(window->updateRegion),
		UI_RECT_SIZE(window->updateRegion));
}

void _UIWindowGetScreenPosition(UIWindow *window, int *_x, int *_y) {
	Window child;
	XTranslateCoordinates(ui.display, window->window, DefaultRootWindow(ui.display), 0, 0, _x, _y, &child);
}

void UIMenuShow(UIMenu *menu) {
	int width, height;
	_UIMenuPrepare(menu, &width, &height);

	for (int i = 0; i < ScreenCount(ui.display); i++) {
		Screen *screen = ScreenOfDisplay(ui.display, i);

		int x, y;
		Window child;
		XTranslateCoordinates(ui.display, screen->root, DefaultRootWindow(ui.display), 0, 0, &x, &y, &child);

		if (menu->pointX >= x && menu->pointX < x + screen->width 
				&& menu->pointY >= y && menu->pointY < y + screen->height) {
			if (menu->pointX + width > x + screen->width) menu->pointX = x + screen->width - width;
			if (menu->pointY + height > y + screen->height) menu->pointY = y + screen->height - height;
			if (menu->pointX < x) menu->pointX = x;
			if (menu->pointY < y) menu->pointY = y;
			if (menu->pointX + width > x + screen->width) width = x + screen->width - menu->pointX;
			if (menu->pointY + height > y + screen->height) height = y + screen->height - menu->pointY;
			break;
		}
	}

	Atom properties[] = {
		XInternAtom(ui.display, "_NET_WM_WINDOW_TYPE", true),
		XInternAtom(ui.display, "_NET_WM_WINDOW_TYPE_DROPDOWN_MENU", true),
		XInternAtom(ui.display, "_MOTIF_WM_HINTS", true),
	};

	XChangeProperty(ui.display, menu->e.window->window, properties[0], XA_ATOM, 32, PropModeReplace, (uint8_t *) properties, 2);
	XSetTransientForHint(ui.display, menu->e.window->window, DefaultRootWindow(ui.display));

	struct Hints {
		int flags;
		int functions;
		int decorations;
		int inputMode;
		int status;
	};

	struct Hints hints = { 0 };
	hints.flags = 2;
	XChangeProperty(ui.display, menu->e.window->window, properties[2], properties[2], 32, PropModeReplace, (uint8_t *) &hints, 5);

	XMapWindow(ui.display, menu->e.window->window);
	XMoveResizeWindow(ui.display, menu->e.window->window, menu->pointX, menu->pointY, width, height);
}

void UIWindowPack(UIWindow *window, int _width) {
	int width = _width ? _width : UIElementMessage(window->e.children, UI_MSG_GET_WIDTH, 0, 0);
	int height = UIElementMessage(window->e.children, UI_MSG_GET_HEIGHT, width, 0);
	XResizeWindow(ui.display, window->window, width, height);
}

bool _UIProcessEvent(XEvent *event) {
	if (event->type == ClientMessage && (Atom) event->xclient.data.l[0] == ui.windowClosedID) {
		UIWindow *window = _UIFindWindow(event->xclient.window);
		if (!window) return false;
		bool exit = !UIElementMessage(&window->e, UI_MSG_WINDOW_CLOSE, 0, 0);
		if (exit) return true;
		_UIUpdate();
		return false;
	} else if (event->type == Expose) {
		UIWindow *window = _UIFindWindow(event->xexpose.window);
		if (!window) return false;
		XPutImage(ui.display, window->window, DefaultGC(ui.display, 0), window->image, 0, 0, 0, 0, window->width, window->height);
	} else if (event->type == ConfigureNotify) {
		UIWindow *window = _UIFindWindow(event->xconfigure.window);
		if (!window) return false;

		if (window->width != event->xconfigure.width || window->height != event->xconfigure.height) {
			window->width = event->xconfigure.width;
			window->height = event->xconfigure.height;
			window->bits = (uint32_t *) UI_REALLOC(window->bits, window->width * window->height * 4);
			window->image->width = window->width;
			window->image->height = window->height;
			window->image->bytes_per_line = window->width * 4;
			window->image->data = (char *) window->bits;
			window->e.bounds = UI_RECT_2S(window->width, window->height);
			window->e.clip = UI_RECT_2S(window->width, window->height);
#ifdef UI_DEBUG
			for (int i = 0; i < window->width * window->height; i++) window->bits[i] = 0xFF00FF;
#endif
			UIElementMessage(&window->e, UI_MSG_LAYOUT, 0, 0);
			_UIUpdate();
		}
	} else if (event->type == MotionNotify) {
		UIWindow *window = _UIFindWindow(event->xmotion.window);
		if (!window) return false;
		window->cursorX = event->xmotion.x;
		window->cursorY = event->xmotion.y;
		_UIWindowInputEvent(window, UI_MSG_MOUSE_MOVE, 0, 0);
	} else if (event->type == LeaveNotify) {
		UIWindow *window = _UIFindWindow(event->xcrossing.window);
		if (!window) return false;

		if (!window->pressed) {
			window->cursorX = -1;
			window->cursorY = -1;
		}

		_UIWindowInputEvent(window, UI_MSG_MOUSE_MOVE, 0, 0);
	} else if (event->type == ButtonPress || event->type == ButtonRelease) {
		UIWindow *window = _UIFindWindow(event->xbutton.window);
		if (!window) return false;
		window->cursorX = event->xbutton.x;
		window->cursorY = event->xbutton.y;

		if (event->xbutton.button >= 1 && event->xbutton.button <= 3) {
			_UIWindowInputEvent(window, (UIMessage) ((event->type == ButtonPress ? UI_MSG_LEFT_DOWN : UI_MSG_LEFT_UP) 
				+ event->xbutton.button * 2 - 2), 0, 0);
		} else if (event->xbutton.button == 4) {
			_UIWindowInputEvent(window, UI_MSG_MOUSE_WHEEL, -72, 0);
		} else if (event->xbutton.button == 5) {
			_UIWindowInputEvent(window, UI_MSG_MOUSE_WHEEL, 72, 0);
		}

		_UIInspectorSetFocusedWindow(window);
	} else if (event->type == KeyPress) {
		UIWindow *window = _UIFindWindow(event->xkey.window);
		if (!window) return false;

		if (event->xkey.x == 0x7123 && event->xkey.y == 0x7456) {
			// HACK! See UIWindowPostMessage.
			UIElementMessage(&window->e, (UIMessage) event->xkey.state, 0, 
				(void *) (((uintptr_t) (event->xkey.time & 0xFFFFFFFF) << 32) 
					| ((uintptr_t) (event->xkey.x_root & 0xFFFF) << 0) 
					| ((uintptr_t) (event->xkey.y_root & 0xFFFF) << 16)));
			_UIUpdate();
		} else {
			char text[32];
			KeySym symbol = NoSymbol;
			Status status;
			// printf("%ld, %s\n", symbol, text);
			UIKeyTyped m = { 0 };
			m.textBytes = Xutf8LookupString(window->xic, &event->xkey, text, sizeof(text) - 1, &symbol, &status); 
			m.text = text;
			m.code = XLookupKeysym(&event->xkey, 0);

			if (symbol == XK_Control_L || symbol == XK_Control_R) {
				window->ctrl = true;
				window->ctrlCode = event->xkey.keycode;
				_UIWindowInputEvent(window, UI_MSG_MOUSE_MOVE, 0, 0);
			} else if (symbol == XK_Shift_L || symbol == XK_Shift_R) {
				window->shift = true;
				window->shiftCode = event->xkey.keycode;
				_UIWindowInputEvent(window, UI_MSG_MOUSE_MOVE, 0, 0);
			} else if (symbol == XK_Alt_L || symbol == XK_Alt_R) {
				window->alt = true;
				window->altCode = event->xkey.keycode;
				_UIWindowInputEvent(window, UI_MSG_MOUSE_MOVE, 0, 0);
			} else if (symbol == XK_KP_Left) {
				m.code = UI_KEYCODE_LEFT;
			} else if (symbol == XK_KP_Right) {
				m.code = UI_KEYCODE_RIGHT;
			} else if (symbol == XK_KP_Up) {
				m.code = UI_KEYCODE_UP;
			} else if (symbol == XK_KP_Down) {
				m.code = UI_KEYCODE_DOWN;
			} else if (symbol == XK_KP_Home) {
				m.code = UI_KEYCODE_HOME;
			} else if (symbol == XK_KP_End) {
				m.code = UI_KEYCODE_END;
			} else if (symbol == XK_KP_Enter) {
				m.code = UI_KEYCODE_ENTER;
			} else if (symbol == XK_KP_Delete) {
				m.code = UI_KEYCODE_DELETE;
			}

			_UIWindowInputEvent(window, UI_MSG_KEY_TYPED, 0, &m);
		}
	} else if (event->type == KeyRelease) {
		UIWindow *window = _UIFindWindow(event->xkey.window);
		if (!window) return false;

		if (event->xkey.keycode == window->ctrlCode) {
			window->ctrl = false;
			_UIWindowInputEvent(window, UI_MSG_MOUSE_MOVE, 0, 0);
		} else if (event->xkey.keycode == window->shiftCode) {
			window->shift = false;
			_UIWindowInputEvent(window, UI_MSG_MOUSE_MOVE, 0, 0);
		} else if (event->xkey.keycode == window->altCode) {
			window->alt = false;
			_UIWindowInputEvent(window, UI_MSG_MOUSE_MOVE, 0, 0);
		}
	} else if (event->type == FocusIn) {
		UIWindow *window = _UIFindWindow(event->xfocus.window);
		if (!window) return false;
		window->ctrl = window->shift = window->alt = false;
		UIElementMessage(&window->e, UI_MSG_WINDOW_ACTIVATE, 0, 0);
	} else if (event->type == ClientMessage && event->xclient.message_type == ui.dndEnterID) {
		UIWindow *window = _UIFindWindow(event->xclient.window);
		if (!window) return false;
		window->dragSource = (Window) event->xclient.data.l[0];
	} else if (event->type == ClientMessage && event->xclient.message_type == ui.dndPositionID) {
		UIWindow *window = _UIFindWindow(event->xclient.window);
		if (!window) return false;
		XClientMessageEvent m = { 0 };
		m.type = ClientMessage;
		m.display = event->xclient.display;
		m.window = (Window) event->xclient.data.l[0];
		m.message_type = ui.dndStatusID;
		m.format = 32;
		m.data.l[0] = window->window;
		m.data.l[1] = true;
		m.data.l[4] = ui.dndActionCopyID;
		XSendEvent(ui.display, m.window, False, NoEventMask, (XEvent *) &m);
		XFlush(ui.display);
	} else if (event->type == ClientMessage && event->xclient.message_type == ui.dndDropID) {
		UIWindow *window = _UIFindWindow(event->xclient.window);
		if (!window) return false;

		// TODO Dropping text.

		if (!XConvertSelection(ui.display, ui.dndSelectionID, ui.uriListID, ui.primaryID, window->window, event->xclient.data.l[2])) {
			XClientMessageEvent m = { 0 };
			m.type = ClientMessage;
			m.display = ui.display;
			m.window = window->dragSource;
			m.message_type = ui.dndFinishedID;
			m.format = 32;
			m.data.l[0] = window->window;
			m.data.l[1] = 0;
			m.data.l[2] = ui.dndActionCopyID;
			XSendEvent(ui.display, m.window, False, NoEventMask, (XEvent *) &m);
			XFlush(ui.display);
		}
	} else if (event->type == SelectionNotify) {
		UIWindow *window = _UIFindWindow(event->xselection.requestor);
		if (!window) return false;
		if (!window->dragSource) return false;

		Atom type = None;
		int format = 0;
		uint64_t count = 0, bytesLeft = 0;
		uint8_t *data = NULL;
		XGetWindowProperty(ui.display, window->window, ui.primaryID, 0, 65536, False, AnyPropertyType, &type, &format, &count, &bytesLeft, &data);

		if (format == 8 /* bits per character */) {
			if (event->xselection.target == ui.uriListID) {
				char *copy = (char *) UI_MALLOC(count);
				int fileCount = 0;

				for (int i = 0; i < (int) count; i++) {
					copy[i] = data[i];

					if (i && data[i - 1] == '\r' && data[i] == '\n') {
						fileCount++;
					}
				}

				char **files = (char **) UI_MALLOC(sizeof(char *) * fileCount);
				fileCount = 0;

				for (int i = 0; i < (int) count; i++) {
					char *s = copy + i;
					while (!(i && data[i - 1] == '\r' && data[i] == '\n' && i < (int) count)) i++;
					copy[i - 1] = 0;

					for (int j = 0; s[j]; j++) {
						if (s[j] == '%' && s[j + 1] && s[j + 2]) {
							char n[3];
							n[0] = s[j + 1], n[1] = s[j + 2], n[2] = 0;
							s[j] = strtol(n, NULL, 16);
							if (!s[j]) break;
							memmove(s + j + 1, s + j + 3, strlen(s) - j - 2);
						}
					}

					if (s[0] == 'f' && s[1] == 'i' && s[2] == 'l' && s[3] == 'e' && s[4] == ':' && s[5] == '/' && s[6] == '/') {
						files[fileCount++] = s + 7;
					}
				}

				UIElementMessage(&window->e, UI_MSG_WINDOW_DROP_FILES, fileCount, files);

				UI_FREE(files);
				UI_FREE(copy);
			} else if (event->xselection.target == ui.plainTextID) {
				// TODO.
			}
		}

		XFree(data);

		XClientMessageEvent m = { 0 };
		m.type = ClientMessage;
		m.display = ui.display;
		m.window = window->dragSource;
		m.message_type = ui.dndFinishedID;
		m.format = 32;
		m.data.l[0] = window->window;
		m.data.l[1] = true;
		m.data.l[2] = ui.dndActionCopyID;
		XSendEvent(ui.display, m.window, False, NoEventMask, (XEvent *) &m);
		XFlush(ui.display);

		window->dragSource = 0; // Drag complete.
		_UIUpdate();
	}

	return false;
}

bool _UIMessageLoopSingle(int *result) {
	XEvent events[64];

	if (ui.animating) {
		if (XPending(ui.display)) {
			XNextEvent(ui.display, events + 0);
		} else {
			_UIProcessAnimations();
			return true;
		}
	} else {
		XNextEvent(ui.display, events + 0);
	}

	int p = 1;

	int configureIndex = -1, motionIndex = -1, exposeIndex = -1;

	while (p < 64 && XPending(ui.display)) {
		XNextEvent(ui.display, events + p);

#define _UI_MERGE_EVENTS(a, b) \
	if (events[p].type == a) { \
		if (b != -1) events[b].type = 0; \
		b = p; \
	}

		_UI_MERGE_EVENTS(ConfigureNotify, configureIndex);
		_UI_MERGE_EVENTS(MotionNotify, motionIndex);
		_UI_MERGE_EVENTS(Expose, exposeIndex);

		p++;
	}

	for (int i = 0; i < p; i++) {
		if (!events[i].type) {
			continue;
		}

		if (_UIProcessEvent(events + i)) {
			return false;
		}
	}

	return true;
}

void UIWindowPostMessage(UIWindow *window, UIMessage message, void *_dp) {
	// HACK! Xlib doesn't seem to have a nice way to do this,
	// so send a specially crafted key press event instead.
	// TODO Maybe ClientMessage is what this should use?
	uintptr_t dp = (uintptr_t) _dp;
	XKeyEvent event = { 0 };
	event.display = ui.display;
	event.window = window->window;
	event.root = DefaultRootWindow(ui.display);
	event.subwindow = None;
	event.time = dp >> 32;
	event.x = 0x7123;
	event.y = 0x7456;
	event.x_root = (dp >> 0) & 0xFFFF;
	event.y_root = (dp >> 16) & 0xFFFF;
	event.same_screen = True;
	event.keycode = 1;
	event.state = message;
	event.type = KeyPress;
	XSendEvent(ui.display, window->window, True, KeyPressMask, (XEvent *) &event);
	XFlush(ui.display);
}

#endif

#ifdef UI_WINDOWS

const int UI_KEYCODE_A = 'A';
const int UI_KEYCODE_0 = '0';
const int UI_KEYCODE_BACKSPACE = VK_BACK;
const int UI_KEYCODE_DELETE = VK_DELETE;
const int UI_KEYCODE_DOWN = VK_DOWN;
const int UI_KEYCODE_END = VK_END;
const int UI_KEYCODE_ENTER = VK_RETURN;
const int UI_KEYCODE_ESCAPE = VK_ESCAPE;
const int UI_KEYCODE_F1 = VK_F1;
const int UI_KEYCODE_HOME = VK_HOME;
const int UI_KEYCODE_LEFT = VK_LEFT;
const int UI_KEYCODE_RIGHT = VK_RIGHT;
const int UI_KEYCODE_SPACE = VK_SPACE;
const int UI_KEYCODE_TAB = VK_TAB;
const int UI_KEYCODE_UP = VK_UP;

int _UIWindowMessage(UIElement *element, UIMessage message, int di, void *dp) {
	if (message == UI_MSG_DESTROY) {
		UIWindow *window = (UIWindow *) element;
		_UIWindowDestroyCommon(window);
		SetWindowLongPtr(window->hwnd, GWLP_USERDATA, 0);
		DestroyWindow(window->hwnd);
	}

	return _UIWindowMessageCommon(element, message, di, dp);
}

LRESULT CALLBACK _UIWindowProcedure(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) {
	UIWindow *window = (UIWindow *) GetWindowLongPtr(hwnd, GWLP_USERDATA);

	if (!window || ui.assertionFailure) {
		return DefWindowProc(hwnd, message, wParam, lParam);
	}

	if (message == WM_CLOSE) {
		if (UIElementMessage(&window->e, UI_MSG_WINDOW_CLOSE, 0, 0)) {
			_UIUpdate();
			return 0;
		} else {
			PostQuitMessage(0);
		}
	} else if (message == WM_SIZE) {
		RECT client;
		GetClientRect(hwnd, &client);
		window->width = client.right;
		window->height = client.bottom;
		window->bits = (uint32_t *) UI_REALLOC(window->bits, window->width * window->height * 4);
		window->e.bounds = UI_RECT_2S(window->width, window->height);
		window->e.clip = UI_RECT_2S(window->width, window->height);
		UIElementMessage(&window->e, UI_MSG_LAYOUT, 0, 0);
		_UIUpdate();
	} else if (message == WM_MOUSEMOVE) {
		if (!window->trackingLeave) {
			window->trackingLeave = true;
			TRACKMOUSEEVENT leave = { 0 };
			leave.cbSize = sizeof(TRACKMOUSEEVENT);
			leave.dwFlags = TME_LEAVE;
			leave.hwndTrack = hwnd;
			TrackMouseEvent(&leave);
		}

		POINT cursor;
		GetCursorPos(&cursor);
		ScreenToClient(hwnd, &cursor);
		window->cursorX = cursor.x;
		window->cursorY = cursor.y;
		_UIWindowInputEvent(window, UI_MSG_MOUSE_MOVE, 0, 0);
	} else if (message == WM_MOUSELEAVE) {
		window->trackingLeave = false;

		if (!window->pressed) {
			window->cursorX = -1;
			window->cursorY = -1;
		}

		_UIWindowInputEvent(window, UI_MSG_MOUSE_MOVE, 0, 0);
	} else if (message == WM_LBUTTONDOWN) {
		SetCapture(hwnd);
		_UIWindowInputEvent(window, UI_MSG_LEFT_DOWN, 0, 0);
	} else if (message == WM_LBUTTONUP) {
		if (window->pressedButton == 1) ReleaseCapture();
		_UIWindowInputEvent(window, UI_MSG_LEFT_UP, 0, 0);
	} else if (message == WM_MBUTTONDOWN) {
		SetCapture(hwnd);
		_UIWindowInputEvent(window, UI_MSG_MIDDLE_DOWN, 0, 0);
	} else if (message == WM_MBUTTONUP) {
		if (window->pressedButton == 2) ReleaseCapture();
		_UIWindowInputEvent(window, UI_MSG_MIDDLE_UP, 0, 0);
	} else if (message == WM_RBUTTONDOWN) {
		SetCapture(hwnd);
		_UIWindowInputEvent(window, UI_MSG_RIGHT_DOWN, 0, 0);
	} else if (message == WM_RBUTTONUP) {
		if (window->pressedButton == 3) ReleaseCapture();
		_UIWindowInputEvent(window, UI_MSG_RIGHT_UP, 0, 0);
	} else if (message == WM_MOUSEWHEEL) {
		int delta = (int) wParam >> 16;
		_UIWindowInputEvent(window, UI_MSG_MOUSE_WHEEL, -delta, 0);
	} else if (message == WM_KEYDOWN) {
		window->ctrl = GetKeyState(VK_CONTROL) & 0x8000;
		window->shift = GetKeyState(VK_SHIFT) & 0x8000;
		window->alt = GetKeyState(VK_MENU) & 0x8000;

		UIKeyTyped m = { 0 };
		m.code = wParam;
		_UIWindowInputEvent(window, UI_MSG_KEY_TYPED, 0, &m);
	} else if (message == WM_CHAR) {
		UIKeyTyped m = { 0 };
		char c = wParam;
		m.text = &c;
		m.textBytes = 1;
		_UIWindowInputEvent(window, UI_MSG_KEY_TYPED, 0, &m);
	} else if (message == WM_PAINT) {
		PAINTSTRUCT paint;
		HDC dc = BeginPaint(hwnd, &paint);
		BITMAPINFOHEADER info = { 0 };
		info.biSize = sizeof(info);
		info.biWidth = window->width, info.biHeight = -window->height;
		info.biPlanes = 1, info.biBitCount = 32;
		StretchDIBits(dc, 0, 0, UI_RECT_SIZE(window->e.bounds), 0, 0, UI_RECT_SIZE(window->e.bounds),
			window->bits, (BITMAPINFO *) &info, DIB_RGB_COLORS, SRCCOPY);
		EndPaint(hwnd, &paint);
	} else if (message == WM_SETCURSOR && LOWORD(lParam) == HTCLIENT) {
		SetCursor(ui.cursors[window->cursorStyle]);
		return 1;
	} else if (message == WM_SETFOCUS || message == WM_KILLFOCUS) {
		_UIMenusClose();

		if (message == WM_SETFOCUS) {
			_UIInspectorSetFocusedWindow(window);
			UIElementMessage(&window->e, UI_MSG_WINDOW_ACTIVATE, 0, 0);
		}
	} else if (message == WM_MOUSEACTIVATE && (window->e.flags & UI_WINDOW_MENU)) {
		return MA_NOACTIVATE;
	} else if (message == WM_DROPFILES) {
		HDROP drop = (HDROP) wParam;
		int count = DragQueryFile(drop, 0xFFFFFFFF, NULL, 0);
		char **files = (char **) UI_MALLOC(sizeof(char *) * count);
		
		for (int i = 0; i < count; i++) {
			int length = DragQueryFile(drop, i, NULL, 0);
			files[i] = (char *) UI_MALLOC(length + 1);
			files[i][length] = 0;
			DragQueryFile(drop, i, files[i], length + 1);
		}
		
		UIElementMessage(&window->e, UI_MSG_WINDOW_DROP_FILES, count, files);
		for (int i = 0; i < count; i++) UI_FREE(files[i]);		
		UI_FREE(files);
		DragFinish(drop);
		_UIUpdate();
	} else if (message == WM_APP + 1) {
		UIElementMessage(&window->e, (UIMessage) wParam, 0, (void *) lParam);
		_UIUpdate();
	} else {
		if (message == WM_NCLBUTTONDOWN || message == WM_NCMBUTTONDOWN || message == WM_NCRBUTTONDOWN) {
			if (~window->e.flags & UI_WINDOW_MENU) {
				_UIMenusClose();
				_UIUpdate();
			}
		}

		return DefWindowProc(hwnd, message, wParam, lParam);
	}

	return 0;
}

void UIInitialise() {
	_UIInitialiseCommon();

	ui.cursors[UI_CURSOR_ARROW] = LoadCursor(NULL, IDC_ARROW);
	ui.cursors[UI_CURSOR_TEXT] = LoadCursor(NULL, IDC_IBEAM);
	ui.cursors[UI_CURSOR_SPLIT_V] = LoadCursor(NULL, IDC_SIZENS);
	ui.cursors[UI_CURSOR_SPLIT_H] = LoadCursor(NULL, IDC_SIZEWE);
	ui.cursors[UI_CURSOR_FLIPPED_ARROW] = LoadCursor(NULL, IDC_ARROW);
	ui.cursors[UI_CURSOR_CROSS_HAIR] = LoadCursor(NULL, IDC_CROSS);
	ui.cursors[UI_CURSOR_HAND] = LoadCursor(NULL, IDC_HAND);
	ui.cursors[UI_CURSOR_RESIZE_UP] = LoadCursor(NULL, IDC_SIZENS);
	ui.cursors[UI_CURSOR_RESIZE_LEFT] = LoadCursor(NULL, IDC_SIZEWE);
	ui.cursors[UI_CURSOR_RESIZE_UP_RIGHT] = LoadCursor(NULL, IDC_SIZENESW);
	ui.cursors[UI_CURSOR_RESIZE_UP_LEFT] = LoadCursor(NULL, IDC_SIZENWSE);
	ui.cursors[UI_CURSOR_RESIZE_DOWN] = LoadCursor(NULL, IDC_SIZENS);
	ui.cursors[UI_CURSOR_RESIZE_RIGHT] = LoadCursor(NULL, IDC_SIZEWE);
	ui.cursors[UI_CURSOR_RESIZE_DOWN_LEFT] = LoadCursor(NULL, IDC_SIZENESW);
	ui.cursors[UI_CURSOR_RESIZE_DOWN_RIGHT] = LoadCursor(NULL, IDC_SIZENWSE);

	ui.heap = GetProcessHeap();

	WNDCLASS windowClass = { 0 };
	windowClass.lpfnWndProc = _UIWindowProcedure;
	windowClass.lpszClassName = "normal";
	RegisterClass(&windowClass);
	windowClass.style |= CS_DROPSHADOW;
	windowClass.lpszClassName = "shadow";
	RegisterClass(&windowClass);
}

bool _UIMessageLoopSingle(int *result) {
	MSG message = { 0 };

	if (ui.animating) {
		if (PeekMessage(&message, NULL, 0, 0, PM_REMOVE)) {
			if (message.message == WM_QUIT) {
				*result = message.wParam;
				return false;
			}

			TranslateMessage(&message);
			DispatchMessage(&message);
		} else {
			_UIProcessAnimations();
		}
	} else {
		if (!GetMessage(&message, NULL, 0, 0)) {
			*result = message.wParam;
			return false;
		}

		TranslateMessage(&message);
		DispatchMessage(&message);
	}

	return true;
}

void UIMenuShow(UIMenu *menu) {
	int width, height;
	_UIMenuPrepare(menu, &width, &height);
	MoveWindow(menu->e.window->hwnd, menu->pointX, menu->pointY, width, height, FALSE);
	ShowWindow(menu->e.window->hwnd, SW_SHOWNOACTIVATE);
}

UIWindow *UIWindowCreate(UIWindow *owner, uint32_t flags, const char *cTitle, int width, int height) {
	_UIMenusClose();

	UIWindow *window = (UIWindow *) UIElementCreate(sizeof(UIWindow), NULL, flags | UI_ELEMENT_WINDOW, _UIWindowMessage, "Window");
	_UIWindowAdd(window);
	if (owner) window->scale = owner->scale;

	if (flags & UI_WINDOW_MENU) {
		UI_ASSERT(owner);

		window->hwnd = CreateWindowEx(WS_EX_TOPMOST | WS_EX_NOACTIVATE, "shadow", 0, WS_POPUP, 
			0, 0, 0, 0, owner->hwnd, NULL, NULL, NULL);
	} else {
		window->hwnd = CreateWindowEx(WS_EX_ACCEPTFILES, "normal", cTitle, WS_OVERLAPPEDWINDOW, 
			CW_USEDEFAULT, CW_USEDEFAULT, width ? width : CW_USEDEFAULT, height ? height : CW_USEDEFAULT,
			owner ? owner->hwnd : NULL, NULL, NULL, NULL);
	}

	SetWindowLongPtr(window->hwnd, GWLP_USERDATA, (LONG_PTR) window);

	if (~flags & UI_WINDOW_MENU) {
		ShowWindow(window->hwnd, SW_SHOW);
		PostMessage(window->hwnd, WM_SIZE, 0, 0);
	}

	return window;
}

void _UIWindowEndPaint(UIWindow *window, UIPainter *painter) {
	HDC dc = GetDC(window->hwnd);
	BITMAPINFOHEADER info = { 0 };
	info.biSize = sizeof(info);
	info.biWidth = window->width, info.biHeight = window->height;
	info.biPlanes = 1, info.biBitCount = 32;
	StretchDIBits(dc, 
		UI_RECT_TOP_LEFT(window->updateRegion), UI_RECT_SIZE(window->updateRegion), 
		window->updateRegion.l, window->updateRegion.b + 1, 
		UI_RECT_WIDTH(window->updateRegion), -UI_RECT_HEIGHT(window->updateRegion),
		window->bits, (BITMAPINFO *) &info, DIB_RGB_COLORS, SRCCOPY);
	ReleaseDC(window->hwnd, dc);
}

void _UIWindowSetCursor(UIWindow *window, int cursor) {
	SetCursor(ui.cursors[cursor]);
}

void _UIWindowGetScreenPosition(UIWindow *window, int *_x, int *_y) {
	POINT p;
	p.x = 0;
	p.y = 0;
	ClientToScreen(window->hwnd, &p);
	*_x = p.x;
	*_y = p.y;
}

void UIWindowPostMessage(UIWindow *window, UIMessage message, void *_dp) {
	PostMessage(window->hwnd, WM_APP + 1, (WPARAM) message, (LPARAM) _dp);
}

void *_UIHeapReAlloc(void *pointer, size_t size) {
	if (pointer) {
		if (size) {
			return HeapReAlloc(ui.heap, 0, pointer, size);
		} else {
			UI_FREE(pointer);
			return NULL;
		}
	} else {
		if (size) {
			return UI_MALLOC(size);
		} else {
			return NULL;
		}
	}
}

#endif

#ifdef UI_ESSENCE

const int UI_KEYCODE_A = ES_SCANCODE_A;
const int UI_KEYCODE_0 = ES_SCANCODE_0;
const int UI_KEYCODE_BACKSPACE = ES_SCANCODE_BACKSPACE;
const int UI_KEYCODE_DELETE = ES_SCANCODE_DELETE;
const int UI_KEYCODE_DOWN = ES_SCANCODE_DOWN_ARROW;
const int UI_KEYCODE_END = ES_SCANCODE_END;
const int UI_KEYCODE_ENTER = ES_SCANCODE_ENTER;
const int UI_KEYCODE_ESCAPE = ES_SCANCODE_ESCAPE;
const int UI_KEYCODE_F1 = ES_SCANCODE_F1;
const int UI_KEYCODE_HOME = ES_SCANCODE_HOME;
const int UI_KEYCODE_LEFT = ES_SCANCODE_LEFT_ARROW;
const int UI_KEYCODE_RIGHT = ES_SCANCODE_RIGHT_ARROW;
const int UI_KEYCODE_SPACE = ES_SCANCODE_SPACE;
const int UI_KEYCODE_TAB = ES_SCANCODE_TAB;
const int UI_KEYCODE_UP = ES_SCANCODE_UP_ARROW;

int _UIWindowMessage(UIElement *element, UIMessage message, int di, void *dp) {
	if (message == UI_MSG_DESTROY) {
		// TODO Non-main windows.
		element->window = NULL;
		EsInstanceDestroy(ui.instance);
	}

	return _UIWindowMessageCommon(element, message, di, dp);
}

void UIInitialise() {
	_UIInitialiseCommon();

	while (true) {
		EsMessage *message = EsMessageReceive();

		if (message->type == ES_MSG_INSTANCE_CREATE) {
			ui.instance = EsInstanceCreate(message, NULL, 0);
			break;
		}
	}
}

bool _UIMessageLoopSingle(int *result) {
	if (ui.animating) {
		// TODO.
	} else {
		_UIMessageProcess(EsMessageReceive());
	}

	return true;
}

UIMenu *UIMenuCreate(UIElement *parent, uint32_t flags) {
	ui.menuIndex = 0;
	return EsMenuCreate(parent->window->window, ES_MENU_AT_CURSOR);
}

void _UIMenuItemCallback(EsMenu *menu, EsGeneric context) {
	((void (*)(void *)) ui.menuData[context.u * 2 + 0])(ui.menuData[context.u * 2 + 1]);
}

void UIMenuAddItem(UIMenu *menu, uint32_t flags, const char *label, ptrdiff_t labelBytes, void (*invoke)(void *cp), void *cp) {
	EsAssert(ui.menuIndex < 128);
	ui.menuData[ui.menuIndex * 2 + 0] = (void *) invoke;
	ui.menuData[ui.menuIndex * 2 + 1] = cp;
	EsMenuAddItem(menu, (flags & UI_BUTTON_CHECKED) ? ES_MENU_ITEM_CHECKED : ES_FLAGS_DEFAULT, 
			label, labelBytes, _UIMenuItemCallback, ui.menuIndex);
	ui.menuIndex++;
}

void UIMenuShow(UIMenu *menu) {
	EsMenuShow(menu);
}

int _UIWindowCanvasMessage(EsElement *element, EsMessage *message) {
	UIWindow *window = (UIWindow *) element->window->userData.p;

	if (!window) {
		return 0;
	} else if (message->type == ES_MSG_PAINT) {
		EsRectangle bounds = ES_RECT_4PD(message->painter->offsetX, message->painter->offsetY, window->width, window->height);
		EsDrawBitmap(message->painter, bounds, window->bits, window->width * 4, 0xFFFF);
	} else if (message->type == ES_MSG_LAYOUT) {
		EsElementGetSize(element, &window->width, &window->height);
		window->bits = (uint32_t *) UI_REALLOC(window->bits, window->width * window->height * 4);
		window->e.bounds = UI_RECT_2S(window->width, window->height);
		window->e.clip = UI_RECT_2S(window->width, window->height);
		UIElementMessage(&window->e, UI_MSG_LAYOUT, 0, 0);
		_UIUpdate();
	} else if (message->type == ES_MSG_SCROLL_WHEEL) {
		_UIWindowInputEvent(window, UI_MSG_MOUSE_WHEEL, -message->scrollWheel.dy, 0);
	} else if (message->type == ES_MSG_MOUSE_MOVED || message->type == ES_MSG_HOVERED_END
			|| message->type == ES_MSG_MOUSE_LEFT_DRAG || message->type == ES_MSG_MOUSE_RIGHT_DRAG || message->type == ES_MSG_MOUSE_MIDDLE_DRAG) {
		EsPoint point = EsMouseGetPosition(element); 
		window->cursorX = point.x, window->cursorY = point.y;
		_UIWindowInputEvent(window, UI_MSG_MOUSE_MOVE, 0, 0);
	} else if (message->type == ES_MSG_KEY_UP) {
		window->ctrl = EsKeyboardIsCtrlHeld();
		window->shift = EsKeyboardIsShiftHeld();
		window->alt = EsKeyboardIsAltHeld();
	} else if (message->type == ES_MSG_KEY_DOWN) {
		window->ctrl = EsKeyboardIsCtrlHeld();
		window->shift = EsKeyboardIsShiftHeld();
		window->alt = EsKeyboardIsAltHeld();
		UIKeyTyped m = { 0 };
		char c[64];
		m.text = c;
		m.textBytes = EsMessageGetInputText(message, c);
		m.code = message->keyboard.scancode;
		return _UIWindowInputEvent(window, UI_MSG_KEY_TYPED, 0, &m) ? ES_HANDLED : 0;
	} else if (message->type == ES_MSG_MOUSE_LEFT_CLICK) {
		_UIInspectorSetFocusedWindow(window);
	} else if (message->type == ES_MSG_USER_START) {
		UIElementMessage(&window->e, (UIMessage) message->user.context1.u, 0, (void *) message->user.context2.p);
		_UIUpdate();
	} else if (message->type == ES_MSG_GET_CURSOR) {
		message->cursorStyle = ES_CURSOR_NORMAL;
		if (window->cursor == UI_CURSOR_TEXT)              message->cursorStyle = ES_CURSOR_TEXT;
		if (window->cursor == UI_CURSOR_SPLIT_V)           message->cursorStyle = ES_CURSOR_SPLIT_VERTICAL;
		if (window->cursor == UI_CURSOR_SPLIT_H)           message->cursorStyle = ES_CURSOR_SPLIT_HORIZONTAL;
		if (window->cursor == UI_CURSOR_FLIPPED_ARROW)     message->cursorStyle = ES_CURSOR_SELECT_LINES;
		if (window->cursor == UI_CURSOR_CROSS_HAIR)        message->cursorStyle = ES_CURSOR_CROSS_HAIR_PICK;
		if (window->cursor == UI_CURSOR_HAND)              message->cursorStyle = ES_CURSOR_HAND_HOVER;
		if (window->cursor == UI_CURSOR_RESIZE_UP)         message->cursorStyle = ES_CURSOR_RESIZE_VERTICAL;
		if (window->cursor == UI_CURSOR_RESIZE_LEFT)       message->cursorStyle = ES_CURSOR_RESIZE_HORIZONTAL;
		if (window->cursor == UI_CURSOR_RESIZE_UP_RIGHT)   message->cursorStyle = ES_CURSOR_RESIZE_DIAGONAL_1;
		if (window->cursor == UI_CURSOR_RESIZE_UP_LEFT)    message->cursorStyle = ES_CURSOR_RESIZE_DIAGONAL_2;
		if (window->cursor == UI_CURSOR_RESIZE_DOWN)       message->cursorStyle = ES_CURSOR_RESIZE_VERTICAL;
		if (window->cursor == UI_CURSOR_RESIZE_RIGHT)      message->cursorStyle = ES_CURSOR_RESIZE_HORIZONTAL;
		if (window->cursor == UI_CURSOR_RESIZE_DOWN_RIGHT) message->cursorStyle = ES_CURSOR_RESIZE_DIAGONAL_1;
		if (window->cursor == UI_CURSOR_RESIZE_DOWN_LEFT)  message->cursorStyle = ES_CURSOR_RESIZE_DIAGONAL_2;
	}
	
	else if (message->type == ES_MSG_MOUSE_LEFT_DOWN)   _UIWindowInputEvent(window, UI_MSG_LEFT_DOWN, 0, 0);
	else if (message->type == ES_MSG_MOUSE_LEFT_UP)     _UIWindowInputEvent(window, UI_MSG_LEFT_UP, 0, 0);
	else if (message->type == ES_MSG_MOUSE_MIDDLE_DOWN) _UIWindowInputEvent(window, UI_MSG_MIDDLE_DOWN, 0, 0);
	else if (message->type == ES_MSG_MOUSE_MIDDLE_UP)   _UIWindowInputEvent(window, UI_MSG_MIDDLE_UP, 0, 0);
	else if (message->type == ES_MSG_MOUSE_RIGHT_DOWN)  _UIWindowInputEvent(window, UI_MSG_RIGHT_DOWN, 0, 0);
	else if (message->type == ES_MSG_MOUSE_RIGHT_UP)    _UIWindowInputEvent(window, UI_MSG_RIGHT_UP, 0, 0);

	else return 0;

	return ES_HANDLED;
}

UIWindow *UIWindowCreate(UIWindow *owner, uint32_t flags, const char *cTitle, int width, int height) {
	_UIMenusClose();

	UIWindow *window = (UIWindow *) UIElementCreate(sizeof(UIWindow), NULL, flags | UI_ELEMENT_WINDOW, _UIWindowMessage, "Window");
	_UIWindowAdd(window);
	if (owner) window->scale = owner->scale;

	if (flags & UI_WINDOW_MENU) {
		// TODO.
	} else {
		// TODO Non-main windows.
		window->window = ui.instance->window;
		window->window->userData = window;
		window->canvas = EsCustomElementCreate(window->window, ES_CELL_FILL | ES_ELEMENT_FOCUSABLE);
		window->canvas->messageUser = _UIWindowCanvasMessage;
		EsWindowSetTitle(window->window, cTitle, -1);
		EsElementFocus(window->canvas);
	}

	return window;
}

void _UIWindowEndPaint(UIWindow *window, UIPainter *painter) {
	EsElementRepaint(window->canvas, &window->updateRegion);
}

void _UIWindowSetCursor(UIWindow *window, int cursor) {
	window->cursor = cursor;
}

void _UIWindowGetScreenPosition(UIWindow *window, int *_x, int *_y) {
	EsRectangle r = EsElementGetScreenBounds(window->window);
	*_x = r.l, *_y = r.t;
}

void UIWindowPostMessage(UIWindow *window, UIMessage message, void *_dp) {
	EsMessage m = {};
	m.type = ES_MSG_USER_START;
	m.user.context1.u = message;
	m.user.context2.p = _dp;
	EsMessagePost(window->canvas, &m);
}

#endif

#endif
