text:
/***************************************************************************/
/*                                                                         */
/*  tttables.h                                                             */
/*                                                                         */
/*    Basic SFNT/TrueType tables definitions and interface                 */
/*    (specification only).                                                */
/*                                                                         */
/*  Copyright 1996-2017 by                                                 */
/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used,       */
/*  modified, and distributed under the terms of the FreeType project      */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/***************************************************************************/

#ifndef TTTABLES_H_
#define TTTABLES_H_

#include <ft2build.h>
#include FT_FREETYPE_H

#ifdef FREETYPE_H
#error "freetype.h of FreeType 1 has been loaded!"
#error "Please fix the directory search order for header files"
#error "so that freetype.h of FreeType 2 is found first."
#endif

FT_BEGIN_HEADER

  /*************************************************************************/
  /*                                                                       */
  /* <Section>                                                             */
  /*    truetype_tables                                                    */
  /*                                                                       */
  /* <Title>                                                               */
  /*    TrueType Tables                                                    */
  /*                                                                       */
  /* <Abstract>                                                            */
  /*    TrueType specific table types and functions.                       */
  /*                                                                       */
  /* <Description>                                                         */
  /*    This section contains definitions of some basic tables specific to */
  /*    TrueType and OpenType as well as some routines used to access and  */
  /*    process them.                                                      */
  /*                                                                       */
  /* <Order>                                                               */
  /*    TT_Header                                                          */
  /*    TT_HoriHeader                                                      */
  /*    TT_VertHeader                                                      */
  /*    TT_OS2                                                             */
  /*    TT_Postscript                                                      */
  /*    TT_PCLT                                                            */
  /*    TT_MaxProfile                                                      */
  /*                                                                       */
  /*    FT_Sfnt_Tag                                                        */
  /*    FT_Get_Sfnt_Table                                                  */
  /*    FT_Load_Sfnt_Table                                                 */
  /*    FT_Sfnt_Table_Info                                                 */
  /*                                                                       */
  /*    FT_Get_CMap_Language_ID                                            */
  /*    FT_Get_CMap_Format                                                 */
  /*                                                                       */
  /*    FT_PARAM_TAG_UNPATENTED_HINTING                                    */
  /*                                                                       */
  /*************************************************************************/

  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    TT_Header                                                          */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A structure to model a TrueType font header table.  All fields     */
  /*    follow the OpenType specification.                                 */
  /*                                                                       */
  typedef struct  TT_Header_
  {
    FT_Fixed   Table_Version;
    FT_Fixed   Font_Revision;

    FT_Long    CheckSum_Adjust;
    FT_Long    Magic_Number;

    FT_UShort  Flags;
    FT_UShort  Units_Per_EM;

    FT_Long    Created [2];
    FT_Long    Modified[2];

    FT_Short   xMin;
    FT_Short   yMin;
    FT_Short   xMax;
    FT_Short   yMax;

    FT_UShort  Mac_Style;
    FT_UShort  Lowest_Rec_PPEM;

    FT_Short   Font_Direction;
    FT_Short   Index_To_Loc_Format;
    FT_Short   Glyph_Data_Format;

  } TT_Header;

  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    TT_HoriHeader                                                      */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A structure to model a TrueType horizontal header, the `hhea'      */
  /*    table, as well as the corresponding horizontal metrics table,      */
  /*    `hmtx'.                                                            */
  /*                                                                       */
  /* <Fields>                                                              */
  /*    Version                :: The table version.                       */
  /*                                                                       */
  /*    Ascender               :: The font's ascender, i.e., the distance  */
  /*                              from the baseline to the top-most of all */
  /*                              glyph points found in the font.          */
  /*                                                                       */
  /*                              This value is invalid in many fonts, as  */
  /*                              it is usually set by the font designer,  */
  /*                              and often reflects only a portion of the */
  /*                              glyphs found in the font (maybe ASCII).  */
  /*                                                                       */
  /*                              You should use the `sTypoAscender' field */
  /*                              of the `OS/2' table instead if you want  */
  /*                              the correct one.                         */
  /*                                                                       */
  /*    Descender              :: The font's descender, i.e., the distance */
  /*                              from the baseline to the bottom-most of  */
  /*                              all glyph points found in the font.  It  */
  /*                              is negative.                             */
  /*                                                                       */
  /*                              This value is invalid in many fonts, as  */
  /*                              it is usually set by the font designer,  */
  /*                              and often reflects only a portion of the */
  /*                              glyphs found in the font (maybe ASCII).  */
  /*                                                                       */
  /*                              You should use the `sTypoDescender'      */
  /*                              field of the `OS/2' table instead if you */
  /*                              want the correct one.                    */
  /*                                                                       */
  /*    Line_Gap               :: The font's line gap, i.e., the distance  */
  /*                              to add to the ascender and descender to  */
  /*                              get the BTB, i.e., the                   */
  /*                              baseline-to-baseline distance for the    */
  /*                              font.                                    */
  /*                                                                       */
  /*    advance_Width_Max      :: This field is the maximum of all advance */
  /*                              widths found in the font.  It can be     */
  /*                              used to compute the maximum width of an  */
  /*                              arbitrary string of text.                */
  /*                                                                       */
  /*    min_Left_Side_Bearing  :: The minimum left side bearing of all     */
  /*                              glyphs within the font.                  */
  /*                                                                       */
  /*    min_Right_Side_Bearing :: The minimum right side bearing of all    */
  /*                              glyphs within the font.                  */
  /*                                                                       */
  /*    xMax_Extent            :: The maximum horizontal extent (i.e., the */
  /*                              `width' of a glyph's bounding box) for   */
  /*                              all glyphs in the font.                  */
  /*                                                                       */
  /*    caret_Slope_Rise       :: The rise coefficient of the cursor's     */
  /*                              slope of the cursor (slope=rise/run).    */
  /*                                                                       */
  /*    caret_Slope_Run        :: The run coefficient of the cursor's      */
  /*                              slope.                                   */
  /*                                                                       */
  /*    caret_Offset           :: The cursor's offset for slanted fonts.   */
  /*                                                                       */
  /*    Reserved               :: 8~reserved bytes.                        */
  /*                                                                       */
  /*    metric_Data_Format     :: Always~0.                                */
  /*                                                                       */
  /*    number_Of_HMetrics     :: Number of HMetrics entries in the `hmtx' */
  /*                              table -- this value can be smaller than  */
  /*                              the total number of glyphs in the font.  */
  /*                                                                       */
  /*    long_metrics           :: A pointer into the `hmtx' table.         */
  /*                                                                       */
  /*    short_metrics          :: A pointer into the `hmtx' table.         */
  /*                                                                       */
  /* <Note>                                                                */
  /*    For an OpenType variation font, the values of the following fields */
  /*    can change after a call to @FT_Set_Var_Design_Coordinates (and     */
  /*    friends) if the font contains an `MVAR' table: `caret_Slope_Rise', */
  /*    `caret_Slope_Run', and `caret_Offset'.                             */
  /*                                                                       */
  typedef struct  TT_HoriHeader_
  {
    FT_Fixed   Version;
    FT_Short   Ascender;
    FT_Short   Descender;
    FT_Short   Line_Gap;

    FT_UShort  advance_Width_Max;      /* advance width maximum */

    FT_Short   min_Left_Side_Bearing;  /* minimum left-sb       */
    FT_Short   min_Right_Side_Bearing; /* minimum right-sb      */
    FT_Short   xMax_Extent;            /* xmax extents          */
    FT_Short   caret_Slope_Rise;
    FT_Short   caret_Slope_Run;
    FT_Short   caret_Offset;

    FT_Short   Reserved[4];

    FT_Short   metric_Data_Format;
    FT_UShort  number_Of_HMetrics;

    /* The following fields are not defined by the OpenType specification */
    /* but they are used to connect the metrics header to the relevant    */
    /* `hmtx' table.                                                      */

    void*      long_metrics;
    void*      short_metrics;

  } TT_HoriHeader;

  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    TT_VertHeader                                                      */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A structure used to model a TrueType vertical header, the `vhea'   */
  /*    table, as well as the corresponding vertical metrics table,        */
  /*    `vmtx'.                                                            */
  /*                                                                       */
  /* <Fields>                                                              */
  /*    Version                 :: The table version.                      */
  /*                                                                       */
  /*    Ascender                :: The font's ascender, i.e., the distance */
  /*                               from the baseline to the top-most of    */
  /*                               all glyph points found in the font.     */
  /*                                                                       */
  /*                               This value is invalid in many fonts, as */
  /*                               it is usually set by the font designer, */
  /*                               and often reflects only a portion of    */
  /*                               the glyphs found in the font (maybe     */
  /*                               ASCII).                                 */
  /*                                                                       */
  /*                               You should use the `sTypoAscender'      */
  /*                               field of the `OS/2' table instead if    */
  /*                               you want the correct one.               */
  /*                                                                       */
  /*    Descender               :: The font's descender, i.e., the         */
  /*                               distance from the baseline to the       */
  /*                               bottom-most of all glyph points found   */
  /*                               in the font.  It is negative.           */
  /*                                                                       */
  /*                               This value is invalid in many fonts, as */
  /*                               it is usually set by the font designer, */
  /*                               and often reflects only a portion of    */
  /*                               the glyphs found in the font (maybe     */
  /*                               ASCII).                                 */
  /*                                                                       */
  /*                               You should use the `sTypoDescender'     */
  /*                               field of the `OS/2' table instead if    */
  /*                               you want the correct one.               */
  /*                                                                       */
  /*    Line_Gap                :: The font's line gap, i.e., the distance */
  /*                               to add to the ascender and descender to */
  /*                               get the BTB, i.e., the                  */
  /*                               baseline-to-baseline distance for the   */
  /*                               font.                                   */
  /*                                                                       */
  /*    advance_Height_Max      :: This field is the maximum of all        */
  /*                               advance heights found in the font.  It  */
  /*                               can be used to compute the maximum      */
  /*                               height of an arbitrary string of text.  */
  /*                                                                       */
  /*    min_Top_Side_Bearing    :: The minimum top side bearing of all     */
  /*                               glyphs within the font.                 */
  /*                                                                       */
  /*    min_Bottom_Side_Bearing :: The minimum bottom side bearing of all  */
  /*                               glyphs within the font.                 */
  /*                                                                       */
  /*    yMax_Extent             :: The maximum vertical extent (i.e., the  */
  /*                               `height' of a glyph's bounding box) for */
  /*                               all glyphs in the font.                 */
  /*                                                                       */
  /*    caret_Slope_Rise        :: The rise coefficient of the cursor's    */
  /*                               slope of the cursor (slope=rise/run).   */
  /*                                                                       */
  /*    caret_Slope_Run         :: The run coefficient of the cursor's     */
  /*                               slope.                                  */
  /*                                                                       */
  /*    caret_Offset            :: The cursor's offset for slanted fonts.  */
  /*                                                                       */
  /*    Reserved                :: 8~reserved bytes.                       */
  /*                                                                       */
  /*    metric_Data_Format      :: Always~0.                               */
  /*                                                                       */
  /*    number_Of_VMetrics      :: Number of VMetrics entries in the       */
  /*                               `vmtx' table -- this value can be       */
  /*                               smaller than the total number of glyphs */
  /*                               in the font.                            */
  /*                                                                       */
  /*    long_metrics            :: A pointer into the `vmtx' table.        */
  /*                                                                       */
  /*    short_metrics           :: A pointer into the `vmtx' table.        */
  /*                                                                       */
  /* <Note>                                                                */
  /*    For an OpenType variation font, the values of the following fields */
  /*    can change after a call to @FT_Set_Var_Design_Coordinates (and     */
  /*    friends) if the font contains an `MVAR' table: `Ascender',         */
  /*    `Descender', `Line_Gap', `caret_Slope_Rise', `caret_Slope_Run',    */
  /*    and `caret_Offset'.                                                */
  /*                                                                       */
  typedef struct  TT_VertHeader_
  {
    FT_Fixed   Version;
    FT_Short   Ascender;
    FT_Short   Descender;
    FT_Short   Line_Gap;

    FT_UShort  advance_Height_Max;      /* advance height maximum */

    FT_Short   min_Top_Side_Bearing;    /* minimum top-sb          */
    FT_Short   min_Bottom_Side_Bearing; /* minimum bottom-sb       */
    FT_Short   yMax_Extent;             /* ymax extents            */
    FT_Short   caret_Slope_Rise;
    FT_Short   caret_Slope_Run;
    FT_Short   caret_Offset;

    FT_Short   Reserved[4];

    FT_Short   metric_Data_Format;
    FT_UShort  number_Of_VMetrics;

    /* The following fields are not defined by the OpenType specification */
    /* but they are used to connect the metrics header to the relevant    */
    /* `vmtx' table.                                                      */

    void*      long_metrics;
    void*      short_metrics;

  } TT_VertHeader;

  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    TT_OS2                                                             */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A structure to model a TrueType `OS/2' table.  All fields comply   */
  /*    to the OpenType specification.                                     */
  /*                                                                       */
  /*    Note that we now support old Mac fonts that do not include an      */
  /*    `OS/2' table.  In this case, the `version' field is always set to  */
  /*    0xFFFF.                                                            */
  /*                                                                       */
  /* <Note>                                                                */
  /*    For an OpenType variation font, the values of the following fields */
  /*    can change after a call to @FT_Set_Var_Design_Coordinates (and     */
  /*    friends) if the font contains an `MVAR' table: `sCapHeight',       */
  /*    `sTypoAscender', `sTypoDescender', `sTypoLineGap', `sxHeight',     */
  /*    `usWinAscent', `usWinDescent', `yStrikeoutPosition',               */
  /*    `yStrikeoutSize', `ySubscriptXOffset', `ySubScriptXSize',          */
  /*    `ySubscriptYOffset', `ySubscriptYSize', `ySuperscriptXOffset',     */
  /*    `ySuperscriptXSize', `ySuperscriptYOffset', and                    */
  /*    `ySuperscriptYSize'.                                               */
  /*                                                                       */
  /*    Possible values for bits in the `ulUnicodeRangeX' fields are given */
  /*    by the @TT_UCR_XXX macros.                                         */
  /*                                                                       */

  typedef struct  TT_OS2_
  {
    FT_UShort  version;                /* 0x0001 - more or 0xFFFF */
    FT_Short   xAvgCharWidth;
    FT_UShort  usWeightClass;
    FT_UShort  usWidthClass;
    FT_UShort  fsType;
    FT_Short   ySubscriptXSize;
    FT_Short   ySubscriptYSize;
    FT_Short   ySubscriptXOffset;
    FT_Short   ySubscriptYOffset;
    FT_Short   ySuperscriptXSize;
    FT_Short   ySuperscriptYSize;
    FT_Short   ySuperscriptXOffset;
    FT_Short   ySuperscriptYOffset;
    FT_Short   yStrikeoutSize;
    FT_Short   yStrikeoutPosition;
    FT_Short   sFamilyClass;

    FT_Byte    panose[10];

    FT_ULong   ulUnicodeRange1;        /* Bits 0-31   */
    FT_ULong   ulUnicodeRange2;        /* Bits 32-63  */
    FT_ULong   ulUnicodeRange3;        /* Bits 64-95  */
    FT_ULong   ulUnicodeRange4;        /* Bits 96-127 */

    FT_Char    achVendID[4];

    FT_UShort  fsSelection;
    FT_UShort  usFirstCharIndex;
    FT_UShort  usLastCharIndex;
    FT_Short   sTypoAscender;
    FT_Short   sTypoDescender;
    FT_Short   sTypoLineGap;
    FT_UShort  usWinAscent;
    FT_UShort  usWinDescent;

    /* only version 1 and higher: */

    FT_ULong   ulCodePageRange1;       /* Bits 0-31   */
    FT_ULong   ulCodePageRange2;       /* Bits 32-63  */

    /* only version 2 and higher: */

    FT_Short   sxHeight;
    FT_Short   sCapHeight;
    FT_UShort  usDefaultChar;
    FT_UShort  usBreakChar;
    FT_UShort  usMaxContext;

    /* only version 5 and higher: */

    FT_UShort  usLowerOpticalPointSize;       /* in twips (1/20th points) */
    FT_UShort  usUpperOpticalPointSize;       /* in twips (1/20th points) */

  } TT_OS2;

  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    TT_Postscript                                                      */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A structure to model a TrueType `post' table.  All fields comply   */
  /*    to the OpenType specification.  This structure does not reference  */
  /*    a font's PostScript glyph names; use @FT_Get_Glyph_Name to         */
  /*    retrieve them.                                                     */
  /*                                                                       */
  /* <Note>                                                                */
  /*    For an OpenType variation font, the values of the following fields */
  /*    can change after a call to @FT_Set_Var_Design_Coordinates (and     */
  /*    friends) if the font contains an `MVAR' table: `underlinePosition' */
  /*    and `underlineThickness'.                                          */
  /*                                                                       */
  typedef struct  TT_Postscript_
  {
    FT_Fixed  FormatType;
    FT_Fixed  italicAngle;
    FT_Short  underlinePosition;
    FT_Short  underlineThickness;
    FT_ULong  isFixedPitch;
    FT_ULong  minMemType42;
    FT_ULong  maxMemType42;
    FT_ULong  minMemType1;
    FT_ULong  maxMemType1;

    /* Glyph names follow in the `post' table, but we don't */
    /* load them by default.                                */

  } TT_Postscript;

  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    TT_PCLT                                                            */
  /*                                                                       */
  /* <Description>                                                         */
  /*    A structure to model a TrueType `PCLT' table.  All fields comply   */
  /*    to the OpenType specification.                                     */
  /*                                                                       */
  typedef struct  TT_PCLT_
  {
    FT_Fixed   Version;
    FT_ULong   FontNumber;
    FT_UShort  Pitch;
    FT_UShort  xHeight;
    FT_UShort  Style;
    FT_UShort  TypeFamily;
    FT_UShort  CapHeight;
    FT_UShort  SymbolSet;
    FT_Char    TypeFace[16];
    FT_Char    CharacterComplement[8];
    FT_Char    FileName[6];
    FT_Char    StrokeWeight;
    FT_Char    WidthType;
    FT_Byte    SerifStyle;
    FT_Byte    Reserved;

  } TT_PCLT;

  /*************************************************************************/
  /*                                                                       */
  /* <Struct>                                                              */
  /*    TT_MaxProfile                                                      */
  /*                                                                       */
  /* <Description>                                                         */
  /*    The maximum profile (`maxp') table contains many max values, which */
  /*    can be used to pre-allocate arrays for speeding up glyph loading   */
  /*    and hinting.                                                       */
  /*                                                                       */
  /* <Fields>                                                              */
  /*    version               :: The version number.                       */
  /*                                                                       */
  /*    numGlyphs             :: The number of glyphs in this TrueType     */
  /*                             font.                                     */
  /*                                                                       */
  /*    maxPoints             :: The maximum number of points in a         */
  /*                             non-composite TrueType glyph.  See also   */
  /*                             `maxCompositePoints'.                     */
  /*                                                                       */
  /*    maxContours           :: The maximum number of contours in a       */
  /*                             non-composite TrueType glyph.  See also   */
  /*                             `maxCompositeContours'.                   */
  /*                                                                       */
  /*    maxCompositePoints    :: The maximum number of points in a         */
  /*                             composite TrueType glyph.  See also       */
  /*                             `maxPoints'.                              */
  /*                                                                       */
  /*    maxCompositeContours  :: The maximum number of contours in a       */
  /*                             composite TrueType glyph.  See also       */
  /*                             `maxContours'.                            */
  /*                                                                       */
  /*    maxZones              :: The maximum number of zones used for      */
  /*                             glyph hinting.                            */
  /*                                                                       */
  /*    maxTwilightPoints     :: The maximum number of points in the       */
  /*                             twilight zone used for glyph hinting.     */
  /*                                                                       */
  /*    maxStorage            :: The maximum number of elements in the     */
  /*                             storage area used for glyph hinting.      */
  /*                                                                       */
  /*    maxFunctionDefs       :: The maximum number of function            */
  /*                             definitions in the TrueType bytecode for  */
  /*                             this font.                                */
  /*                                                                       */
  /*    maxInstructionDefs    :: The maximum number of instruction         */
  /*                             definitions in the TrueType bytecode for  */
  /*                             this font.                                */
  /*                                                                       */
  /*    maxStackElements      :: The maximum number of stack elements used */
  /*                             during bytecode interpretation.           */
  /*                                                                       */
  /*    maxSizeOfInstructions :: The maximum number of TrueType opcodes    */
  /*                             used for glyph hinting.                   */
  /*                                                                       */
  /*    maxComponentElements  :: The maximum number of simple (i.e., non-  */
  /*                             composite) glyphs in a composite glyph.   */
  /*                                                                       */
  /*    maxComponentDepth     :: The maximum nesting depth of composite    */
  /*                             glyphs.                                   */
  /*                                                                       */
  /* <Note>                                                                */
  /*    This structure is only used during font loading.                   */
  /*                                                                       */
  typedef struct  TT_MaxProfile_
  {
    FT_Fixed   version;
    FT_UShort  numGlyphs;
    FT_UShort  maxPoints;
    FT_UShort  maxContours;
    FT_UShort  maxCompositePoints;
    FT_UShort  maxCompositeContours;
    FT_UShort  maxZones;
    FT_UShort  maxTwilightPoints;
    FT_UShort  maxStorage;
    FT_UShort  maxFunctionDefs;
    FT_UShort  maxInstructionDefs;
    FT_UShort  maxStackElements;
    FT_UShort  maxSizeOfInstructions;
    FT_UShort  maxComponentElements;
    FT_UShort  maxComponentDepth;

  } TT_MaxProfile;

  /*************************************************************************/
  /*                                                                       */
  /* <Enum>                                                                */
  /*    FT_Sfnt_Tag                                                        */
  /*                                                                       */
  /* <Description>                                                         */
  /*    An enumeration to specify indices of SFNT tables loaded and parsed */
  /*    by FreeType during initialization of an SFNT font.  Used in the    */
  /*    @FT_Get_Sfnt_Table API function.                                   */
  /*                                                                       */
  /* <Values>                                                              */
  /*    FT_SFNT_HEAD :: To access the font's @TT_Header structure.         */
  /*                                                                       */
  /*    FT_SFNT_MAXP :: To access the font's @TT_MaxProfile structure.     */
  /*                                                                       */
  /*    FT_SFNT_OS2  :: To access the font's @TT_OS2 structure.            */
  /*                                                                       */
  /*    FT_SFNT_HHEA :: To access the font's @TT_HoriHeader structure.     */
  /*                                                                       */
  /*    FT_SFNT_VHEA :: To access the font's @TT_VertHeader structure.     */
  /*                                                                       */
  /*    FT_SFNT_POST :: To access the font's @TT_Postscript structure.     */
  /*                                                                       */
  /*    FT_SFNT_PCLT :: To access the font's @TT_PCLT structure.           */
  /*                                                                       */
  typedef enum  FT_Sfnt_Tag_
  {
    FT_SFNT_HEAD,
    FT_SFNT_MAXP,
    FT_SFNT_OS2,
    FT_SFNT_HHEA,
    FT_SFNT_VHEA,
    FT_SFNT_POST,
    FT_SFNT_PCLT,

    FT_SFNT_MAX

  } FT_Sfnt_Tag;

  /* these constants are deprecated; use the corresponding `FT_Sfnt_Tag' */
  /* values instead                                                      */
#define ft_sfnt_head  FT_SFNT_HEAD
#define ft_sfnt_maxp  FT_SFNT_MAXP
#define ft_sfnt_os2   FT_SFNT_OS2
#define ft_sfnt_hhea  FT_SFNT_HHEA
#define ft_sfnt_vhea  FT_SFNT_VHEA
#define ft_sfnt_post  FT_SFNT_POST
#define ft_sfnt_pclt  FT_SFNT_PCLT

  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FT_Get_Sfnt_Table                                                  */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Return a pointer to a given SFNT table stored within a face.       */
  /*                                                                       */
  /* <Input>                                                               */
  /*    face :: A handle to the source.                                    */
  /*                                                                       */
  /*    tag  :: The index of the SFNT table.                               */
  /*                                                                       */
  /* <Return>                                                              */
  /*    A type-less pointer to the table.  This will be NULL in case of    */
  /*    error, or if the corresponding table was not found *OR* loaded     */
  /*    from the file.                                                     */
  /*                                                                       */
  /*    Use a typecast according to `tag' to access the structure          */
  /*    elements.                                                          */
  /*                                                                       */
  /* <Note>                                                                */
  /*    The table is owned by the face object and disappears with it.      */
  /*                                                                       */
  /*    This function is only useful to access SFNT tables that are loaded */
  /*    by the sfnt, truetype, and opentype drivers.  See @FT_Sfnt_Tag for */
  /*    a list.                                                            */
  /*                                                                       */
  /*    Here an example how to access the `vhea' table:                    */
  /*                                                                       */
  /*    {                                                                  */
  /*      TT_VertHeader*  vert_header;                                     */
  /*                                                                       */
  /*                                                                       */
  /*      vert_header =                                                    */
  /*        (TT_VertHeader*)FT_Get_Sfnt_Table( face, FT_SFNT_VHEA );       */
  /*    }                                                                  */
  /*                                                                       */
  FT_EXPORT( void* )
  FT_Get_Sfnt_Table( FT_Face      face,
                     FT_Sfnt_Tag  tag );

  /**************************************************************************
   *
   * @function:
   *   FT_Load_Sfnt_Table
   *
   * @description:
   *   Load any SFNT font table into client memory.
   *
   * @input:
   *   face ::
   *     A handle to the source face.
   *
   *   tag ::
   *     The four-byte tag of the table to load.  Use value~0 if you want
   *     to access the whole font file.  Otherwise, you can use one of the
   *     definitions found in the @FT_TRUETYPE_TAGS_H file, or forge a new
   *     one with @FT_MAKE_TAG.
   *
   *   offset ::
   *     The starting offset in the table (or file if tag~==~0).
   *
   * @output:
   *   buffer ::
   *     The target buffer address.  The client must ensure that the memory
   *     array is big enough to hold the data.
   *
   * @inout:
   *   length ::
   *     If the `length' parameter is NULL, try to load the whole table.
   *     Return an error code if it fails.
   *
   *     Else, if `*length' is~0, exit immediately while returning the
   *     table's (or file) full size in it.
   *
   *     Else the number of bytes to read from the table or file, from the
   *     starting offset.
   *
   * @return:
   *   FreeType error code.  0~means success.
   *
   * @note:
   *   If you need to determine the table's length you should first call this
   *   function with `*length' set to~0, as in the following example:
   *
   *     {
   *       FT_ULong  length = 0;
   *
   *
   *       error = FT_Load_Sfnt_Table( face, tag, 0, NULL, &length );
   *       if ( error ) { ... table does not exist ... }
   *
   *       buffer = malloc( length );
   *       if ( buffer == NULL ) { ... not enough memory ... }
   *
   *       error = FT_Load_Sfnt_Table( face, tag, 0, buffer, &length );
   *       if ( error ) { ... could not load table ... }
   *     }
   *
   *   Note that structures like @TT_Header or @TT_OS2 can't be used with
   *   this function; they are limited to @FT_Get_Sfnt_Table.  Reason is that
   *   those structures depend on the processor architecture, with varying
   *   size (e.g. 32bit vs. 64bit) or order (big endian vs. little endian).
   *
   */
  FT_EXPORT( FT_Error )
  FT_Load_Sfnt_Table( FT_Face    face,
                      FT_ULong   tag,
                      FT_Long    offset,
                      FT_Byte*   buffer,
                      FT_ULong*  length );

  /**************************************************************************
   *
   * @function:
   *   FT_Sfnt_Table_Info
   *
   * @description:
   *   Return information on an SFNT table.
   *
   * @input:
   *   face ::
   *     A handle to the source face.
   *
   *   table_index ::
   *     The index of an SFNT table.  The function returns
   *     FT_Err_Table_Missing for an invalid value.
   *
   * @inout:
   *   tag ::
   *     The name tag of the SFNT table.  If the value is NULL, `table_index'
   *     is ignored, and `length' returns the number of SFNT tables in the
   *     font.
   *
   * @output:
   *   length ::
   *     The length of the SFNT table (or the number of SFNT tables, depending
   *     on `tag').
   *
   * @return:
   *   FreeType error code.  0~means success.
   *
   * @note:
   *   While parsing fonts, FreeType handles SFNT tables with length zero as
   *   missing.
   *
   */
  FT_EXPORT( FT_Error )
  FT_Sfnt_Table_Info( FT_Face    face,
                      FT_UInt    table_index,
                      FT_ULong  *tag,
                      FT_ULong  *length );

  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FT_Get_CMap_Language_ID                                            */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Return cmap language ID as specified in the OpenType standard.     */
  /*    Definitions of language ID values are in file @FT_TRUETYPE_IDS_H.  */
  /*                                                                       */
  /* <Input>                                                               */
  /*    charmap ::                                                         */
  /*      The target charmap.                                              */
  /*                                                                       */
  /* <Return>                                                              */
  /*    The language ID of `charmap'.  If `charmap' doesn't belong to an   */
  /*    SFNT face, just return~0 as the default value.                     */
  /*                                                                       */
  /*    For a format~14 cmap (to access Unicode IVS), the return value is  */
  /*    0xFFFFFFFF.                                                        */
  /*                                                                       */
  FT_EXPORT( FT_ULong )
  FT_Get_CMap_Language_ID( FT_CharMap  charmap );

  /*************************************************************************/
  /*                                                                       */
  /* <Function>                                                            */
  /*    FT_Get_CMap_Format                                                 */
  /*                                                                       */
  /* <Description>                                                         */
  /*    Return the format of an SFNT `cmap' table.                         */
  /*                                                                       */
  /* <Input>                                                               */
  /*    charmap ::                                                         */
  /*      The target charmap.                                              */
  /*                                                                       */
  /* <Return>                                                              */
  /*    The format of `charmap'.  If `charmap' doesn't belong to an SFNT   */
  /*    face, return -1.                                                   */
  /*                                                                       */
  FT_EXPORT( FT_Long )
  FT_Get_CMap_Format( FT_CharMap  charmap );

  /* */

FT_END_HEADER

#endif /* TTTABLES_H_ */

/* END */

repo_name: JoshParnell/libphx

repo_language: C

mime_type: text/x-c++


text:
/***************************************************************************/
/*                                                                         */
/*  fterrdef.h                                                             */
/*                                                                         */
/*    FreeType error codes (specification).                                */
/*                                                                         */
/*  Copyright 2002-2017 by                                                 */
/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used,       */
/*  modified, and distributed under the terms of the FreeType project      */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/***************************************************************************/

  /*************************************************************************/
  /*                                                                       */
  /* <Section>                                                             */
  /*   error_code_values                                                   */
  /*                                                                       */
  /* <Title>                                                               */
  /*   Error Code Values                                                   */
  /*                                                                       */
  /* <Abstract>                                                            */
  /*   All possible error codes returned by FreeType functions.            */
  /*                                                                       */
  /* <Description>                                                         */
  /*   The list below is taken verbatim from the file `fterrdef.h'         */
  /*   (loaded automatically by including `FT_FREETYPE_H').  The first     */
  /*   argument of the `FT_ERROR_DEF_' macro is the error label; by        */
  /*   default, the prefix `FT_Err_' gets added so that you get error      */
  /*   names like `FT_Err_Cannot_Open_Resource'.  The second argument is   */
  /*   the error code, and the last argument an error string, which is not */
  /*   used by FreeType.                                                   */
  /*                                                                       */
  /*   Within your application you should *only* use error names and       */
  /*   *never* its numeric values!  The latter might (and actually do)     */
  /*   change in forthcoming FreeType versions.                            */
  /*                                                                       */
  /*   Macro `FT_NOERRORDEF_' defines `FT_Err_Ok', which is always zero.   */
  /*   See the `Error Enumerations' subsection how to automatically        */
  /*   generate a list of error strings.                                   */
  /*                                                                       */
  /*************************************************************************/

  /*************************************************************************/
  /*                                                                       */
  /* <Enum>                                                                */
  /*    FT_Err_XXX                                                         */
  /*                                                                       */
  /*************************************************************************/

  /* generic errors */

  FT_NOERRORDEF_( Ok,                                        0x00,
                  "no error" )

  FT_ERRORDEF_( Cannot_Open_Resource,                        0x01,
                "cannot open resource" )
  FT_ERRORDEF_( Unknown_File_Format,                         0x02,
                "unknown file format" )
  FT_ERRORDEF_( Invalid_File_Format,                         0x03,
                "broken file" )
  FT_ERRORDEF_( Invalid_Version,                             0x04,
                "invalid FreeType version" )
  FT_ERRORDEF_( Lower_Module_Version,                        0x05,
                "module version is too low" )
  FT_ERRORDEF_( Invalid_Argument,                            0x06,
                "invalid argument" )
  FT_ERRORDEF_( Unimplemented_Feature,                       0x07,
                "unimplemented feature" )
  FT_ERRORDEF_( Invalid_Table,                               0x08,
                "broken table" )
  FT_ERRORDEF_( Invalid_Offset,                              0x09,
                "broken offset within table" )
  FT_ERRORDEF_( Array_Too_Large,                             0x0A,
                "array allocation size too large" )
  FT_ERRORDEF_( Missing_Module,                              0x0B,
                "missing module" )
  FT_ERRORDEF_( Missing_Property,                            0x0C,
                "missing property" )

  /* glyph/character errors */

  FT_ERRORDEF_( Invalid_Glyph_Index,                         0x10,
                "invalid glyph index" )
  FT_ERRORDEF_( Invalid_Character_Code,                      0x11,
                "invalid character code" )
  FT_ERRORDEF_( Invalid_Glyph_Format,                        0x12,
                "unsupported glyph image format" )
  FT_ERRORDEF_( Cannot_Render_Glyph,                         0x13,
                "cannot render this glyph format" )
  FT_ERRORDEF_( Invalid_Outline,                             0x14,
                "invalid outline" )
  FT_ERRORDEF_( Invalid_Composite,                           0x15,
                "invalid composite glyph" )
  FT_ERRORDEF_( Too_Many_Hints,                              0x16,
                "too many hints" )
  FT_ERRORDEF_( Invalid_Pixel_Size,                          0x17,
                "invalid pixel size" )

  /* handle errors */

  FT_ERRORDEF_( Invalid_Handle,                              0x20,
                "invalid object handle" )
  FT_ERRORDEF_( Invalid_Library_Handle,                      0x21,
                "invalid library handle" )
  FT_ERRORDEF_( Invalid_Driver_Handle,                       0x22,
                "invalid module handle" )
  FT_ERRORDEF_( Invalid_Face_Handle,                         0x23,
                "invalid face handle" )
  FT_ERRORDEF_( Invalid_Size_Handle,                         0x24,
                "invalid size handle" )
  FT_ERRORDEF_( Invalid_Slot_Handle,                         0x25,
                "invalid glyph slot handle" )
  FT_ERRORDEF_( Invalid_CharMap_Handle,                      0x26,
                "invalid charmap handle" )
  FT_ERRORDEF_( Invalid_Cache_Handle,                        0x27,
                "invalid cache manager handle" )
  FT_ERRORDEF_( Invalid_Stream_Handle,                       0x28,
                "invalid stream handle" )

  /* driver errors */

  FT_ERRORDEF_( Too_Many_Drivers,                            0x30,
                "too many modules" )
  FT_ERRORDEF_( Too_Many_Extensions,                         0x31,
                "too many extensions" )

  /* memory errors */

  FT_ERRORDEF_( Out_Of_Memory,                               0x40,
                "out of memory" )
  FT_ERRORDEF_( Unlisted_Object,                             0x41,
                "unlisted object" )

  /* stream errors */

  FT_ERRORDEF_( Cannot_Open_Stream,                          0x51,
                "cannot open stream" )
  FT_ERRORDEF_( Invalid_Stream_Seek,                         0x52,
                "invalid stream seek" )
  FT_ERRORDEF_( Invalid_Stream_Skip,                         0x53,
                "invalid stream skip" )
  FT_ERRORDEF_( Invalid_Stream_Read,                         0x54,
                "invalid stream read" )
  FT_ERRORDEF_( Invalid_Stream_Operation,                    0x55,
                "invalid stream operation" )
  FT_ERRORDEF_( Invalid_Frame_Operation,                     0x56,
                "invalid frame operation" )
  FT_ERRORDEF_( Nested_Frame_Access,                         0x57,
                "nested frame access" )
  FT_ERRORDEF_( Invalid_Frame_Read,                          0x58,
                "invalid frame read" )

  /* raster errors */

  FT_ERRORDEF_( Raster_Uninitialized,                        0x60,
                "raster uninitialized" )
  FT_ERRORDEF_( Raster_Corrupted,                            0x61,
                "raster corrupted" )
  FT_ERRORDEF_( Raster_Overflow,                             0x62,
                "raster overflow" )
  FT_ERRORDEF_( Raster_Negative_Height,                      0x63,
                "negative height while rastering" )

  /* cache errors */

  FT_ERRORDEF_( Too_Many_Caches,                             0x70,
                "too many registered caches" )

  /* TrueType and SFNT errors */

  FT_ERRORDEF_( Invalid_Opcode,                              0x80,
                "invalid opcode" )
  FT_ERRORDEF_( Too_Few_Arguments,                           0x81,
                "too few arguments" )
  FT_ERRORDEF_( Stack_Overflow,                              0x82,
                "stack overflow" )
  FT_ERRORDEF_( Code_Overflow,                               0x83,
                "code overflow" )
  FT_ERRORDEF_( Bad_Argument,                                0x84,
                "bad argument" )
  FT_ERRORDEF_( Divide_By_Zero,                              0x85,
                "division by zero" )
  FT_ERRORDEF_( Invalid_Reference,                           0x86,
                "invalid reference" )
  FT_ERRORDEF_( Debug_OpCode,                                0x87,
                "found debug opcode" )
  FT_ERRORDEF_( ENDF_In_Exec_Stream,                         0x88,
                "found ENDF opcode in execution stream" )
  FT_ERRORDEF_( Nested_DEFS,                                 0x89,
                "nested DEFS" )
  FT_ERRORDEF_( Invalid_CodeRange,                           0x8A,
                "invalid code range" )
  FT_ERRORDEF_( Execution_Too_Long,                          0x8B,
                "execution context too long" )
  FT_ERRORDEF_( Too_Many_Function_Defs,                      0x8C,
                "too many function definitions" )
  FT_ERRORDEF_( Too_Many_Instruction_Defs,                   0x8D,
                "too many instruction definitions" )
  FT_ERRORDEF_( Table_Missing,                               0x8E,
                "SFNT font table missing" )
  FT_ERRORDEF_( Horiz_Header_Missing,                        0x8F,
                "horizontal header (hhea) table missing" )
  FT_ERRORDEF_( Locations_Missing,                           0x90,
                "locations (loca) table missing" )
  FT_ERRORDEF_( Name_Table_Missing,                          0x91,
                "name table missing" )
  FT_ERRORDEF_( CMap_Table_Missing,                          0x92,
                "character map (cmap) table missing" )
  FT_ERRORDEF_( Hmtx_Table_Missing,                          0x93,
                "horizontal metrics (hmtx) table missing" )
  FT_ERRORDEF_( Post_Table_Missing,                          0x94,
                "PostScript (post) table missing" )
  FT_ERRORDEF_( Invalid_Horiz_Metrics,                       0x95,
                "invalid horizontal metrics" )
  FT_ERRORDEF_( Invalid_CharMap_Format,                      0x96,
                "invalid character map (cmap) format" )
  FT_ERRORDEF_( Invalid_PPem,                                0x97,
                "invalid ppem value" )
  FT_ERRORDEF_( Invalid_Vert_Metrics,                        0x98,
                "invalid vertical metrics" )
  FT_ERRORDEF_( Could_Not_Find_Context,                      0x99,
                "could not find context" )
  FT_ERRORDEF_( Invalid_Post_Table_Format,                   0x9A,
                "invalid PostScript (post) table format" )
  FT_ERRORDEF_( Invalid_Post_Table,                          0x9B,
                "invalid PostScript (post) table" )
  FT_ERRORDEF_( DEF_In_Glyf_Bytecode,                        0x9C,
                "found FDEF or IDEF opcode in glyf bytecode" )

  /* CFF, CID, and Type 1 errors */

  FT_ERRORDEF_( Syntax_Error,                                0xA0,
                "opcode syntax error" )
  FT_ERRORDEF_( Stack_Underflow,                             0xA1,
                "argument stack underflow" )
  FT_ERRORDEF_( Ignore,                                      0xA2,
                "ignore" )
  FT_ERRORDEF_( No_Unicode_Glyph_Name,                       0xA3,
                "no Unicode glyph name found" )
  FT_ERRORDEF_( Glyph_Too_Big,                               0xA4,
                "glyph too big for hinting" )

  /* BDF errors */

  FT_ERRORDEF_( Missing_Startfont_Field,                     0xB0,
                "`STARTFONT' field missing" )
  FT_ERRORDEF_( Missing_Font_Field,                          0xB1,
                "`FONT' field missing" )
  FT_ERRORDEF_( Missing_Size_Field,                          0xB2,
                "`SIZE' field missing" )
  FT_ERRORDEF_( Missing_Fontboundingbox_Field,               0xB3,
                "`FONTBOUNDINGBOX' field missing" )
  FT_ERRORDEF_( Missing_Chars_Field,                         0xB4,
                "`CHARS' field missing" )
  FT_ERRORDEF_( Missing_Startchar_Field,                     0xB5,
                "`STARTCHAR' field missing" )
  FT_ERRORDEF_( Missing_Encoding_Field,                      0xB6,
                "`ENCODING' field missing" )
  FT_ERRORDEF_( Missing_Bbx_Field,                           0xB7,
                "`BBX' field missing" )
  FT_ERRORDEF_( Bbx_Too_Big,                                 0xB8,
                "`BBX' too big" )
  FT_ERRORDEF_( Corrupted_Font_Header,                       0xB9,
                "Font header corrupted or missing fields" )
  FT_ERRORDEF_( Corrupted_Font_Glyphs,                       0xBA,
                "Font glyphs corrupted or missing fields" )

  /* */

/* END */


text:
/***************************************************************************/
/*                                                                         */
/*  ftcid.h                                                                */
/*                                                                         */
/*    FreeType API for accessing CID font information (specification).     */
/*                                                                         */
/*  Copyright 2007-2017 by                                                 */
/*  Dereg Clegg and Michael Toftdal.                                       */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used,       */
/*  modified, and distributed under the terms of the FreeType project      */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/***************************************************************************/

#ifndef FTCID_H_
#define FTCID_H_

#include <ft2build.h>
#include FT_FREETYPE_H

#ifdef FREETYPE_H
#error "freetype.h of FreeType 1 has been loaded!"
#error "Please fix the directory search order for header files"
#error "so that freetype.h of FreeType 2 is found first."
#endif

FT_BEGIN_HEADER

  /*************************************************************************/
  /*                                                                       */
  /* <Section>                                                             */
  /*    cid_fonts                                                          */
  /*                                                                       */
  /* <Title>                                                               */
  /*    CID Fonts                                                          */
  /*                                                                       */
  /* <Abstract>                                                            */
  /*    CID-keyed font specific API.                                       */
  /*                                                                       */
  /* <Description>                                                         */
  /*    This section contains the declaration of CID-keyed font specific   */
  /*    functions.                                                         */
  /*                                                                       */
  /*************************************************************************/

  /**********************************************************************
   *
   * @function:
   *    FT_Get_CID_Registry_Ordering_Supplement
   *
   * @description:
   *    Retrieve the Registry/Ordering/Supplement triple (also known as the
   *    "R/O/S") from a CID-keyed font.
   *
   * @input:
   *    face ::
   *       A handle to the input face.
   *
   * @output:
   *    registry ::
   *       The registry, as a C~string, owned by the face.
   *
   *    ordering ::
   *       The ordering, as a C~string, owned by the face.
   *
   *    supplement ::
   *       The supplement.
   *
   * @return:
   *    FreeType error code.  0~means success.
   *
   * @note:
   *    This function only works with CID faces, returning an error
   *    otherwise.
   *
   * @since:
   *    2.3.6
   */
  FT_EXPORT( FT_Error )
  FT_Get_CID_Registry_Ordering_Supplement( FT_Face       face,
                                           const char*  *registry,
                                           const char*  *ordering,
                                           FT_Int       *supplement);

  /**********************************************************************
   *
   * @function:
   *    FT_Get_CID_Is_Internally_CID_Keyed
   *
   * @description:
   *    Retrieve the type of the input face, CID keyed or not.  In
   *    contrast to the @FT_IS_CID_KEYED macro this function returns
   *    successfully also for CID-keyed fonts in an SFNT wrapper.
   *
   * @input:
   *    face ::
   *       A handle to the input face.
   *
   * @output:
   *    is_cid ::
   *       The type of the face as an @FT_Bool.
   *
   * @return:
   *    FreeType error code.  0~means success.
   *
   * @note:
   *    This function only works with CID faces and OpenType fonts,
   *    returning an error otherwise.
   *
   * @since:
   *    2.3.9
   */
  FT_EXPORT( FT_Error )
  FT_Get_CID_Is_Internally_CID_Keyed( FT_Face   face,
                                      FT_Bool  *is_cid );

  /**********************************************************************
   *
   * @function:
   *    FT_Get_CID_From_Glyph_Index
   *
   * @description:
   *    Retrieve the CID of the input glyph index.
   *
   * @input:
   *    face ::
   *       A handle to the input face.
   *
   *    glyph_index ::
   *       The input glyph index.
   *
   * @output:
   *    cid ::
   *       The CID as an @FT_UInt.
   *
   * @return:
   *    FreeType error code.  0~means success.
   *
   * @note:
   *    This function only works with CID faces and OpenType fonts,
   *    returning an error otherwise.
   *
   * @since:
   *    2.3.9
   */
  FT_EXPORT( FT_Error )
  FT_Get_CID_From_Glyph_Index( FT_Face   face,
                               FT_UInt   glyph_index,
                               FT_UInt  *cid );

  /* */

FT_END_HEADER

#endif /* FTCID_H_ */

/* END */


text:
/***************************************************************************/
/*                                                                         */
/*  ftlcdfil.h                                                             */
/*                                                                         */
/*    FreeType API for color filtering of subpixel bitmap glyphs           */
/*    (specification).                                                     */
/*                                                                         */
/*  Copyright 2006-2017 by                                                 */
/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used,       */
/*  modified, and distributed under the terms of the FreeType project      */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/***************************************************************************/

#ifndef FTLCDFIL_H_
#define FTLCDFIL_H_

#include <ft2build.h>
#include FT_FREETYPE_H

#ifdef FREETYPE_H
#error "freetype.h of FreeType 1 has been loaded!"
#error "Please fix the directory search order for header files"
#error "so that freetype.h of FreeType 2 is found first."
#endif

FT_BEGIN_HEADER

  /***************************************************************************
   *
   * @section:
   *   lcd_filtering
   *
   * @title:
   *   LCD Filtering
   *
   * @abstract:
   *   Reduce color fringes of subpixel-rendered bitmaps.
   *
   * @description:
   *   Subpixel rendering exploits the color-striped structure of LCD
   *   pixels, increasing the available resolution in the direction of the
   *   stripe (usually horizontal RGB) by a factor of~3.  Since these
   *   subpixels are color pixels, using them unfiltered creates severe
   *   color fringes.  Use the @FT_Library_SetLcdFilter API to specify a
   *   low-pass filter, which is then applied to subpixel-rendered bitmaps
   *   generated through @FT_Render_Glyph.  The filter sacrifices some of
   *   the higher resolution to reduce color fringes, making the glyph image
   *   slightly blurrier.  Positional improvements will remain.
   *
   *   Note that no filter is active by default, and that this function is
   *   *not* implemented in default builds of the library.  You need to
   *   #define FT_CONFIG_OPTION_SUBPIXEL_RENDERING in your `ftoption.h' file
   *   in order to activate it and explicitly call @FT_Library_SetLcdFilter
   *   to enable it.
   *
   *   A filter should have two properties:
   *
   *   1) It should be normalized, meaning the sum of the 5~components
   *      should be 256 (0x100).  It is possible to go above or under this
   *      target sum, however: going under means tossing out contrast, going
   *      over means invoking clamping and thereby non-linearities that
   *      increase contrast somewhat at the expense of greater distortion
   *      and color-fringing.  Contrast is better enhanced through stem
   *      darkening.
   *
   *   2) It should be color-balanced, meaning a filter `{~a, b, c, b, a~}'
   *      where a~+ b~=~c.  It distributes the computed coverage for one
   *      subpixel to all subpixels equally, sacrificing some won resolution
   *      but drastically reducing color-fringing.  Positioning improvements
   *      remain!  Note that color-fringing can only really be minimized
   *      when using a color-balanced filter and alpha-blending the glyph
   *      onto a surface in linear space; see @FT_Render_Glyph.
   *
   *   Regarding the form, a filter can be a `boxy' filter or a `beveled'
   *   filter.  Boxy filters are sharper but are less forgiving of non-ideal
   *   gamma curves of a screen (viewing angles!), beveled filters are
   *   fuzzier but more tolerant.
   *
   *   Examples:
   *
   *   - [0x10 0x40 0x70 0x40 0x10] is beveled and neither balanced nor
   *     normalized.
   *
   *   - [0x1A 0x33 0x4D 0x33 0x1A] is beveled and balanced but not
   *     normalized.
   *
   *   - [0x19 0x33 0x66 0x4c 0x19] is beveled and normalized but not
   *     balanced.
   *
   *   - [0x00 0x4c 0x66 0x4c 0x00] is boxily beveled and normalized but not
   *     balanced.
   *
   *   - [0x00 0x55 0x56 0x55 0x00] is boxy, normalized, and almost
   *     balanced.
   *
   *   - [0x08 0x4D 0x56 0x4D 0x08] is beveled, normalized and, almost
   *     balanced.
   *
   *   The filter affects glyph bitmaps rendered through @FT_Render_Glyph,
   *   @FT_Load_Glyph, and @FT_Load_Char.  It does _not_ affect the output
   *   of @FT_Outline_Render and @FT_Outline_Get_Bitmap.
   *
   *   If this feature is activated, the dimensions of LCD glyph bitmaps are
   *   either wider or taller than the dimensions of the corresponding
   *   outline with regard to the pixel grid.  For example, for
   *   @FT_RENDER_MODE_LCD, the filter adds 3~subpixels to the left, and
   *   3~subpixels to the right.  The bitmap offset values are adjusted
   *   accordingly, so clients shouldn't need to modify their layout and
   *   glyph positioning code when enabling the filter.
   *
   *   It is important to understand that linear alpha blending and gamma
   *   correction is critical for correctly rendering glyphs onto surfaces
   *   without artifacts and even more critical when subpixel rendering is
   *   involved.
   *
   *   Each of the 3~alpha values (subpixels) is independently used to blend
   *   one color channel.  That is, red alpha blends the red channel of the
   *   text color with the red channel of the background pixel.  The
   *   distribution of density values by the color-balanced filter assumes
   *   alpha blending is done in linear space; only then color artifacts
   *   cancel out.
   */

  /****************************************************************************
   *
   * @enum:
   *   FT_LcdFilter
   *
   * @description:
   *   A list of values to identify various types of LCD filters.
   *
   * @values:
   *   FT_LCD_FILTER_NONE ::
   *     Do not perform filtering.  When used with subpixel rendering, this
   *     results in sometimes severe color fringes.
   *
   *   FT_LCD_FILTER_DEFAULT ::
   *     The default filter reduces color fringes considerably, at the cost
   *     of a slight blurriness in the output.
   *
   *     It is a beveled, normalized, and color-balanced five-tap filter
   *     that is more forgiving to screens with non-ideal gamma curves and
   *     viewing angles.  Note that while color-fringing is reduced, it can
   *     only be minimized by using linear alpha blending and gamma
   *     correction to render glyphs onto surfaces.  The default filter
   *     weights are [0x08 0x4D 0x56 0x4D 0x08].
   *
   *   FT_LCD_FILTER_LIGHT ::
   *     The light filter is a variant that is sharper at the cost of
   *     slightly more color fringes than the default one.
   *
   *     It is a boxy, normalized, and color-balanced three-tap filter that
   *     is less forgiving to screens with non-ideal gamma curves and
   *     viewing angles.  This filter works best when the rendering system
   *     uses linear alpha blending and gamma correction to render glyphs
   *     onto surfaces.  The light filter weights are
   *     [0x00 0x55 0x56 0x55 0x00].
   *
   *   FT_LCD_FILTER_LEGACY ::
   *     This filter corresponds to the original libXft color filter.  It
   *     provides high contrast output but can exhibit really bad color
   *     fringes if glyphs are not extremely well hinted to the pixel grid.
   *     In other words, it only works well if the TrueType bytecode
   *     interpreter is enabled *and* high-quality hinted fonts are used.
   *
   *     This filter is only provided for comparison purposes, and might be
   *     disabled or stay unsupported in the future.
   *
   *   FT_LCD_FILTER_LEGACY1 ::
   *     For historical reasons, the FontConfig library returns a different
   *     enumeration value for legacy LCD filtering.  To make code work that
   *     (incorrectly) forwards FontConfig's enumeration value to
   *     @FT_Library_SetLcdFilter without proper mapping, it is thus easiest
   *     to have another enumeration value, which is completely equal to
   *     `FT_LCD_FILTER_LEGACY'.
   *
   * @since:
   *   2.3.0 (`FT_LCD_FILTER_LEGACY1' since 2.6.2)
   */
  typedef enum  FT_LcdFilter_
  {
    FT_LCD_FILTER_NONE    = 0,
    FT_LCD_FILTER_DEFAULT = 1,
    FT_LCD_FILTER_LIGHT   = 2,
    FT_LCD_FILTER_LEGACY1 = 3,
    FT_LCD_FILTER_LEGACY  = 16,

    FT_LCD_FILTER_MAX   /* do not remove */

  } FT_LcdFilter;

  /**************************************************************************
   *
   * @func:
   *   FT_Library_SetLcdFilter
   *
   * @description:
   *   This function is used to apply color filtering to LCD decimated
   *   bitmaps, like the ones used when calling @FT_Render_Glyph with
   *   @FT_RENDER_MODE_LCD or @FT_RENDER_MODE_LCD_V.
   *
   * @input:
   *   library ::
   *     A handle to the target library instance.
   *
   *   filter ::
   *     The filter type.
   *
   *     You can use @FT_LCD_FILTER_NONE here to disable this feature, or
   *     @FT_LCD_FILTER_DEFAULT to use a default filter that should work
   *     well on most LCD screens.
   *
   * @return:
   *   FreeType error code.  0~means success.
   *
   * @note:
   *   This feature is always disabled by default.  Clients must make an
   *   explicit call to this function with a `filter' value other than
   *   @FT_LCD_FILTER_NONE in order to enable it.
   *
   *   Due to *PATENTS* covering subpixel rendering, this function doesn't
   *   do anything except returning `FT_Err_Unimplemented_Feature' if the
   *   configuration macro FT_CONFIG_OPTION_SUBPIXEL_RENDERING is not
   *   defined in your build of the library, which should correspond to all
   *   default builds of FreeType.
   *
   * @since:
   *   2.3.0
   */
  FT_EXPORT( FT_Error )
  FT_Library_SetLcdFilter( FT_Library    library,
                           FT_LcdFilter  filter );

  /**************************************************************************
   *
   * @func:
   *   FT_Library_SetLcdFilterWeights
   *
   * @description:
   *   This function can be used to enable LCD filter with custom weights,
   *   instead of using presets in @FT_Library_SetLcdFilter.
   *
   * @input:
   *   library ::
   *     A handle to the target library instance.
   *
   *   weights ::
   *     A pointer to an array; the function copies the first five bytes and
   *     uses them to specify the filter weights.
   *
   * @return:
   *   FreeType error code.  0~means success.
   *
   * @note:
   *   Due to *PATENTS* covering subpixel rendering, this function doesn't
   *   do anything except returning `FT_Err_Unimplemented_Feature' if the
   *   configuration macro FT_CONFIG_OPTION_SUBPIXEL_RENDERING is not
   *   defined in your build of the library, which should correspond to all
   *   default builds of FreeType.
   *
   *   LCD filter weights can also be set per face using @FT_Face_Properties
   *   with @FT_PARAM_TAG_LCD_FILTER_WEIGHTS.
   *
   * @since:
   *   2.4.0
   */
  FT_EXPORT( FT_Error )
  FT_Library_SetLcdFilterWeights( FT_Library      library,
                                  unsigned char  *weights );

  /**************************************************************************
   *
   * @constant:
   *   FT_PARAM_TAG_LCD_FILTER_WEIGHTS
   *
   * @description:
   *   An @FT_Parameter tag to be used with @FT_Face_Properties.  The
   *   corresponding argument specifies the five LCD filter weights for a
   *   given face (if using @FT_LOAD_TARGET_LCD, for example), overriding
   *   the global default values or the values set up with
   *   @FT_Library_SetLcdFilterWeights.
   *
   */
#define FT_PARAM_TAG_LCD_FILTER_WEIGHTS \
          FT_MAKE_TAG( 'l', 'c', 'd', 'f' )

  /*
   * @type:
   *   FT_LcdFiveTapFilter
   *
   * @description:
   *   A typedef for passing the five LCD filter weights to
   *   @FT_Face_Properties within an @FT_Parameter structure.
   *
   */
#define FT_LCD_FILTER_FIVE_TAPS  5

  typedef FT_Byte  FT_LcdFiveTapFilter[FT_LCD_FILTER_FIVE_TAPS];

  /* */

FT_END_HEADER

#endif /* FTLCDFIL_H_ */

/* END */