/**************************************************************************** * * tttables.h * * Basic SFNT/TrueType tables definitions and interface * (specification only). * * Copyright (C) 1996-2023 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. */ 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`. */ 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`. */ 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. */ 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`. */ TT_Postscript; /************************************************************************** * * @struct: * TT_PCLT * * @description: * A structure to model a TrueType 'PCLT' table. All fields comply to * the OpenType specification. */ 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. */ 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. */ FT_Sfnt_Tag; /* these constants are deprecated; use the corresponding `FT_Sfnt_Tag` */ /* values instead */ #define ft_sfnt_head … #define ft_sfnt_maxp … #define ft_sfnt_os2 … #define ft_sfnt_hhea … #define ft_sfnt_vhea … #define ft_sfnt_post … #define 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 */
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