ref: 5e32a03496327d6e73fc108a315d76511dd41a50
dir: /include/freetype/tttables.h/
/****************************************************************************
*
* tttables.h
*
* Basic SFNT/TrueType tables definitions and interface
* (specification only).
*
* Copyright (C) 1996-2021 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 <freetype/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. The 64-bit timestamps are stored in
* two-element arrays `Created` and `Modified`, first the upper then
* the lower 32~bits.
*/
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_ULong Created [2];
FT_ULong 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.
*
* @example:
* Here is an example demonstrating access to 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 */