ref: 799d27b0b68008d427df1a55e761e3f5b42bd3f6
dir: /include/freetype/freetype.h/
/**************************************************************************** * * freetype.h * * FreeType high-level API and common types (specification only). * * Copyright 1996-2018 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 FREETYPE_H_ #define FREETYPE_H_ #ifndef FT_FREETYPE_H #error "`ft2build.h' hasn't been included yet!" #error "Please always use macros to include FreeType header files." #error "Example:" #error " #include <ft2build.h>" #error " #include FT_FREETYPE_H" #endif #include <ft2build.h> #include FT_CONFIG_CONFIG_H #include FT_TYPES_H #include FT_ERRORS_H FT_BEGIN_HEADER /************************************************************************** * * @section: * header_inclusion * * @title: * FreeType's header inclusion scheme * * @abstract: * How client applications should include FreeType header files. * * @description: * To be as flexible as possible (and for historical reasons), * FreeType uses a very special inclusion scheme to load header * files, for example * * { * #include <ft2build.h> * * #include FT_FREETYPE_H * #include FT_OUTLINE_H * } * * A compiler and its preprocessor only needs an include path to find * the file `ft2build.h'; the exact locations and names of the other * FreeType header files are hidden by @header_file_macros, loaded by * `ft2build.h'. The API documentation always gives the header macro * name needed for a particular function. * */ /************************************************************************** * * @section: * user_allocation * * @title: * User allocation * * @abstract: * How client applications should allocate FreeType data structures. * * @description: * FreeType assumes that structures allocated by the user and passed * as arguments are zeroed out except for the actual data. In other * words, it is recommended to use `calloc' (or variants of it) * instead of `malloc' for allocation. * */ /*************************************************************************/ /*************************************************************************/ /* */ /* B A S I C T Y P E S */ /* */ /*************************************************************************/ /*************************************************************************/ /************************************************************************** * * @section: * base_interface * * @title: * Base Interface * * @abstract: * The FreeType~2 base font interface. * * @description: * This section describes the most important public high-level API * functions of FreeType~2. * * @order: * FT_Library * FT_Face * FT_Size * FT_GlyphSlot * FT_CharMap * FT_Encoding * FT_ENC_TAG * * FT_FaceRec * * FT_FACE_FLAG_SCALABLE * FT_FACE_FLAG_FIXED_SIZES * FT_FACE_FLAG_FIXED_WIDTH * FT_FACE_FLAG_HORIZONTAL * FT_FACE_FLAG_VERTICAL * FT_FACE_FLAG_COLOR * FT_FACE_FLAG_SFNT * FT_FACE_FLAG_CID_KEYED * FT_FACE_FLAG_TRICKY * FT_FACE_FLAG_KERNING * FT_FACE_FLAG_MULTIPLE_MASTERS * FT_FACE_FLAG_VARIATION * FT_FACE_FLAG_GLYPH_NAMES * FT_FACE_FLAG_EXTERNAL_STREAM * FT_FACE_FLAG_HINTER * * FT_HAS_HORIZONTAL * FT_HAS_VERTICAL * FT_HAS_KERNING * FT_HAS_FIXED_SIZES * FT_HAS_GLYPH_NAMES * FT_HAS_COLOR * FT_HAS_MULTIPLE_MASTERS * * FT_IS_SFNT * FT_IS_SCALABLE * FT_IS_FIXED_WIDTH * FT_IS_CID_KEYED * FT_IS_TRICKY * FT_IS_NAMED_INSTANCE * FT_IS_VARIATION * * FT_STYLE_FLAG_BOLD * FT_STYLE_FLAG_ITALIC * * FT_SizeRec * FT_Size_Metrics * * FT_GlyphSlotRec * FT_Glyph_Metrics * FT_SubGlyph * * FT_Bitmap_Size * * FT_Init_FreeType * FT_Done_FreeType * * FT_New_Face * FT_Done_Face * FT_Reference_Face * FT_New_Memory_Face * FT_Face_Properties * FT_Open_Face * FT_Open_Args * FT_Parameter * FT_Attach_File * FT_Attach_Stream * * FT_Set_Char_Size * FT_Set_Pixel_Sizes * FT_Request_Size * FT_Select_Size * FT_Size_Request_Type * FT_Size_RequestRec * FT_Size_Request * FT_Set_Transform * FT_Load_Glyph * FT_Get_Char_Index * FT_Get_First_Char * FT_Get_Next_Char * FT_Get_Name_Index * FT_Load_Char * * FT_OPEN_MEMORY * FT_OPEN_STREAM * FT_OPEN_PATHNAME * FT_OPEN_DRIVER * FT_OPEN_PARAMS * * FT_LOAD_DEFAULT * FT_LOAD_RENDER * FT_LOAD_MONOCHROME * FT_LOAD_LINEAR_DESIGN * FT_LOAD_NO_SCALE * FT_LOAD_NO_HINTING * FT_LOAD_NO_BITMAP * FT_LOAD_NO_AUTOHINT * FT_LOAD_COLOR * * FT_LOAD_VERTICAL_LAYOUT * FT_LOAD_IGNORE_TRANSFORM * FT_LOAD_FORCE_AUTOHINT * FT_LOAD_NO_RECURSE * FT_LOAD_PEDANTIC * * FT_LOAD_TARGET_NORMAL * FT_LOAD_TARGET_LIGHT * FT_LOAD_TARGET_MONO * FT_LOAD_TARGET_LCD * FT_LOAD_TARGET_LCD_V * * FT_LOAD_TARGET_MODE * * FT_Render_Glyph * FT_Render_Mode * FT_Get_Kerning * FT_Kerning_Mode * FT_Get_Track_Kerning * FT_Get_Glyph_Name * FT_Get_Postscript_Name * * FT_CharMapRec * FT_Select_Charmap * FT_Set_Charmap * FT_Get_Charmap_Index * * FT_Get_FSType_Flags * FT_Get_SubGlyph_Info * * FT_Face_Internal * FT_Size_Internal * FT_Slot_Internal * * FT_FACE_FLAG_XXX * FT_STYLE_FLAG_XXX * FT_OPEN_XXX * FT_LOAD_XXX * FT_LOAD_TARGET_XXX * FT_SUBGLYPH_FLAG_XXX * FT_FSTYPE_XXX * * FT_HAS_FAST_GLYPHS * */ /************************************************************************** * * @struct: * FT_Glyph_Metrics * * @description: * A structure to model the metrics of a single glyph. The values * are expressed in 26.6 fractional pixel format; if the flag * @FT_LOAD_NO_SCALE has been used while loading the glyph, values * are expressed in font units instead. * * @fields: * width :: * The glyph's width. * * height :: * The glyph's height. * * horiBearingX :: * Left side bearing for horizontal layout. * * horiBearingY :: * Top side bearing for horizontal layout. * * horiAdvance :: * Advance width for horizontal layout. * * vertBearingX :: * Left side bearing for vertical layout. * * vertBearingY :: * Top side bearing for vertical layout. Larger positive values * mean further below the vertical glyph origin. * * vertAdvance :: * Advance height for vertical layout. Positive values mean the * glyph has a positive advance downward. * * @note: * If not disabled with @FT_LOAD_NO_HINTING, the values represent * dimensions of the hinted glyph (in case hinting is applicable). * * Stroking a glyph with an outside border does not increase * `horiAdvance' or `vertAdvance'; you have to manually adjust these * values to account for the added width and height. * * FreeType doesn't use the `VORG' table data for CFF fonts because * it doesn't have an interface to quickly retrieve the glyph height. * The y~coordinate of the vertical origin can be simply computed as * `vertBearingY + height' after loading a glyph. */ typedef struct FT_Glyph_Metrics_ { FT_Pos width; FT_Pos height; FT_Pos horiBearingX; FT_Pos horiBearingY; FT_Pos horiAdvance; FT_Pos vertBearingX; FT_Pos vertBearingY; FT_Pos vertAdvance; } FT_Glyph_Metrics; /************************************************************************** * * @struct: * FT_Bitmap_Size * * @description: * This structure models the metrics of a bitmap strike (i.e., a set * of glyphs for a given point size and resolution) in a bitmap font. * It is used for the `available_sizes' field of @FT_Face. * * @fields: * height :: * The vertical distance, in pixels, between two * consecutive baselines. It is always positive. * * width :: * The average width, in pixels, of all glyphs in the * strike. * * size :: * The nominal size of the strike in 26.6 fractional * points. This field is not very useful. * * x_ppem :: * The horizontal ppem (nominal width) in 26.6 fractional * pixels. * * y_ppem :: * The vertical ppem (nominal height) in 26.6 fractional * pixels. * * @note: * Windows FNT: * The nominal size given in a FNT font is not reliable. If the * driver finds it incorrect, it sets `size' to some calculated * values, and `x_ppem' and `y_ppem' to the pixel width and height * given in the font, respectively. * * TrueType embedded bitmaps: * `size', `width', and `height' values are not contained in the * bitmap strike itself. They are computed from the global font * parameters. */ typedef struct FT_Bitmap_Size_ { FT_Short height; FT_Short width; FT_Pos size; FT_Pos x_ppem; FT_Pos y_ppem; } FT_Bitmap_Size; /*************************************************************************/ /*************************************************************************/ /* */ /* O B J E C T C L A S S E S */ /* */ /*************************************************************************/ /*************************************************************************/ /************************************************************************** * * @type: * FT_Library * * @description: * A handle to a FreeType library instance. Each `library' is * completely independent from the others; it is the `root' of a set * of objects like fonts, faces, sizes, etc. * * It also embeds a memory manager (see @FT_Memory), as well as a * scan-line converter object (see @FT_Raster). * * In multi-threaded applications it is easiest to use one * `FT_Library' object per thread. In case this is too cumbersome, * a single `FT_Library' object across threads is possible also * (since FreeType version 2.5.6), as long as a mutex lock is used * around @FT_New_Face and @FT_Done_Face. * * @note: * Library objects are normally created by @FT_Init_FreeType, and * destroyed with @FT_Done_FreeType. If you need reference-counting * (cf. @FT_Reference_Library), use @FT_New_Library and * @FT_Done_Library. */ typedef struct FT_LibraryRec_ *FT_Library; /************************************************************************** * * @section: * module_management * */ /************************************************************************** * * @type: * FT_Module * * @description: * A handle to a given FreeType module object. A module can be a * font driver, a renderer, or anything else that provides services * to the former. */ typedef struct FT_ModuleRec_* FT_Module; /************************************************************************** * * @type: * FT_Driver * * @description: * A handle to a given FreeType font driver object. A font driver * is a module capable of creating faces from font files. */ typedef struct FT_DriverRec_* FT_Driver; /************************************************************************** * * @type: * FT_Renderer * * @description: * A handle to a given FreeType renderer. A renderer is a module in * charge of converting a glyph's outline image to a bitmap. It * supports a single glyph image format, and one or more target * surface depths. */ typedef struct FT_RendererRec_* FT_Renderer; /************************************************************************** * * @section: * base_interface * */ /************************************************************************** * * @type: * FT_Face * * @description: * A handle to a typographic face object. A face object models a * given typeface, in a given style. * * @note: * A face object also owns a single @FT_GlyphSlot object, as well * as one or more @FT_Size objects. * * Use @FT_New_Face or @FT_Open_Face to create a new face object from * a given filepath or a custom input stream. * * Use @FT_Done_Face to destroy it (along with its slot and sizes). * * An `FT_Face' object can only be safely used from one thread at a * time. Similarly, creation and destruction of `FT_Face' with the * same @FT_Library object can only be done from one thread at a * time. On the other hand, functions like @FT_Load_Glyph and its * siblings are thread-safe and do not need the lock to be held as * long as the same `FT_Face' object is not used from multiple * threads at the same time. * * @also: * See @FT_FaceRec for the publicly accessible fields of a given face * object. */ typedef struct FT_FaceRec_* FT_Face; /************************************************************************** * * @type: * FT_Size * * @description: * A handle to an object that models a face scaled to a given * character size. * * @note: * An @FT_Face has one _active_ @FT_Size object that is used by * functions like @FT_Load_Glyph to determine the scaling * transformation that in turn is used to load and hint glyphs and * metrics. * * You can use @FT_Set_Char_Size, @FT_Set_Pixel_Sizes, * @FT_Request_Size or even @FT_Select_Size to change the content * (i.e., the scaling values) of the active @FT_Size. * * You can use @FT_New_Size to create additional size objects for a * given @FT_Face, but they won't be used by other functions until * you activate it through @FT_Activate_Size. Only one size can be * activated at any given time per face. * * @also: * See @FT_SizeRec for the publicly accessible fields of a given size * object. */ typedef struct FT_SizeRec_* FT_Size; /************************************************************************** * * @type: * FT_GlyphSlot * * @description: * A handle to a given `glyph slot'. A slot is a container that can * hold any of the glyphs contained in its parent face. * * In other words, each time you call @FT_Load_Glyph or * @FT_Load_Char, the slot's content is erased by the new glyph data, * i.e., the glyph's metrics, its image (bitmap or outline), and * other control information. * * @also: * See @FT_GlyphSlotRec for the publicly accessible glyph fields. */ typedef struct FT_GlyphSlotRec_* FT_GlyphSlot; /************************************************************************** * * @type: * FT_CharMap * * @description: * A handle to a character map (usually abbreviated to `charmap'). A * charmap is used to translate character codes in a given encoding * into glyph indexes for its parent's face. Some font formats may * provide several charmaps per font. * * Each face object owns zero or more charmaps, but only one of them * can be `active', providing the data used by @FT_Get_Char_Index or * @FT_Load_Char. * * The list of available charmaps in a face is available through the * `face->num_charmaps' and `face->charmaps' fields of @FT_FaceRec. * * The currently active charmap is available as `face->charmap'. * You should call @FT_Set_Charmap to change it. * * @note: * When a new face is created (either through @FT_New_Face or * @FT_Open_Face), the library looks for a Unicode charmap within * the list and automatically activates it. If there is no Unicode * charmap, FreeType doesn't set an `active' charmap. * * @also: * See @FT_CharMapRec for the publicly accessible fields of a given * character map. */ typedef struct FT_CharMapRec_* FT_CharMap; /************************************************************************** * * @macro: * FT_ENC_TAG * * @description: * This macro converts four-letter tags into an unsigned long. It is * used to define `encoding' identifiers (see @FT_Encoding). * * @note: * Since many 16-bit compilers don't like 32-bit enumerations, you * should redefine this macro in case of problems to something like * this: * * { * #define FT_ENC_TAG( value, a, b, c, d ) value * } * * to get a simple enumeration without assigning special numbers. */ #ifndef FT_ENC_TAG #define FT_ENC_TAG( value, a, b, c, d ) \ value = ( ( (FT_UInt32)(a) << 24 ) | \ ( (FT_UInt32)(b) << 16 ) | \ ( (FT_UInt32)(c) << 8 ) | \ (FT_UInt32)(d) ) #endif /* FT_ENC_TAG */ /************************************************************************** * * @enum: * FT_Encoding * * @description: * An enumeration to specify character sets supported by charmaps. * Used in the @FT_Select_Charmap API function. * * @note: * Despite the name, this enumeration lists specific character * repertories (i.e., charsets), and not text encoding methods (e.g., * UTF-8, UTF-16, etc.). * * Other encodings might be defined in the future. * * @values: * FT_ENCODING_NONE :: * The encoding value~0 is reserved for all formats except BDF, PCF, * and Windows FNT; see below for more information. * * FT_ENCODING_UNICODE :: * The Unicode character set. This value covers all versions of * the Unicode repertoire, including ASCII and Latin-1. Most fonts * include a Unicode charmap, but not all of them. * * For example, if you want to access Unicode value U+1F028 (and * the font contains it), use value 0x1F028 as the input value for * @FT_Get_Char_Index. * * FT_ENCODING_MS_SYMBOL :: * Microsoft Symbol encoding, used to encode mathematical symbols * and wingdings. For more information, see * `https://www.microsoft.com/typography/otspec/recom.htm', * `http://www.kostis.net/charsets/symbol.htm', and * `http://www.kostis.net/charsets/wingding.htm'. * * This encoding uses character codes from the PUA (Private Unicode * Area) in the range U+F020-U+F0FF. * * FT_ENCODING_SJIS :: * Shift JIS encoding for Japanese. More info at * `https://en.wikipedia.org/wiki/Shift_JIS'. See note on * multi-byte encodings below. * * FT_ENCODING_PRC :: * Corresponds to encoding systems mainly for Simplified Chinese as * used in People's Republic of China (PRC). The encoding layout * is based on GB~2312 and its supersets GBK and GB~18030. * * FT_ENCODING_BIG5 :: * Corresponds to an encoding system for Traditional Chinese as * used in Taiwan and Hong Kong. * * FT_ENCODING_WANSUNG :: * Corresponds to the Korean encoding system known as Extended * Wansung (MS Windows code page 949). * For more information see * `https://www.unicode.org/Public/MAPPINGS/VENDORS/MICSFT/WindowsBestFit/bestfit949.txt'. * * FT_ENCODING_JOHAB :: * The Korean standard character set (KS~C 5601-1992), which * corresponds to MS Windows code page 1361. This character set * includes all possible Hangul character combinations. * * FT_ENCODING_ADOBE_LATIN_1 :: * Corresponds to a Latin-1 encoding as defined in a Type~1 * PostScript font. It is limited to 256 character codes. * * FT_ENCODING_ADOBE_STANDARD :: * Adobe Standard encoding, as found in Type~1, CFF, and * OpenType/CFF fonts. It is limited to 256 character codes. * * FT_ENCODING_ADOBE_EXPERT :: * Adobe Expert encoding, as found in Type~1, CFF, and OpenType/CFF * fonts. It is limited to 256 character codes. * * FT_ENCODING_ADOBE_CUSTOM :: * Corresponds to a custom encoding, as found in Type~1, CFF, and * OpenType/CFF fonts. It is limited to 256 character codes. * * FT_ENCODING_APPLE_ROMAN :: * Apple roman encoding. Many TrueType and OpenType fonts contain * a charmap for this 8-bit encoding, since older versions of Mac * OS are able to use it. * * FT_ENCODING_OLD_LATIN_2 :: * This value is deprecated and was neither used nor reported by * FreeType. Don't use or test for it. * * FT_ENCODING_MS_SJIS :: * Same as FT_ENCODING_SJIS. Deprecated. * * FT_ENCODING_MS_GB2312 :: * Same as FT_ENCODING_PRC. Deprecated. * * FT_ENCODING_MS_BIG5 :: * Same as FT_ENCODING_BIG5. Deprecated. * * FT_ENCODING_MS_WANSUNG :: * Same as FT_ENCODING_WANSUNG. Deprecated. * * FT_ENCODING_MS_JOHAB :: * Same as FT_ENCODING_JOHAB. Deprecated. * * @note: * By default, FreeType enables a Unicode charmap and tags it with * FT_ENCODING_UNICODE when it is either provided or can be generated * from PostScript glyph name dictionaries in the font file. * All other encodings are considered legacy and tagged only if * explicitly defined in the font file. Otherwise, FT_ENCODING_NONE * is used. * * FT_ENCODING_NONE is set by the BDF and PCF drivers if the charmap * is neither Unicode nor ISO-8859-1 (otherwise it is set to * FT_ENCODING_UNICODE). Use @FT_Get_BDF_Charset_ID to find out * which encoding is really present. If, for example, the * `cs_registry' field is `KOI8' and the `cs_encoding' field is `R', * the font is encoded in KOI8-R. * * FT_ENCODING_NONE is always set (with a single exception) by the * winfonts driver. Use @FT_Get_WinFNT_Header and examine the * `charset' field of the @FT_WinFNT_HeaderRec structure to find out * which encoding is really present. For example, * @FT_WinFNT_ID_CP1251 (204) means Windows code page 1251 (for * Russian). * * FT_ENCODING_NONE is set if `platform_id' is @TT_PLATFORM_MACINTOSH * and `encoding_id' is not `TT_MAC_ID_ROMAN' (otherwise it is set to * FT_ENCODING_APPLE_ROMAN). * * If `platform_id' is @TT_PLATFORM_MACINTOSH, use the function * @FT_Get_CMap_Language_ID to query the Mac language ID that may * be needed to be able to distinguish Apple encoding variants. See * * https://www.unicode.org/Public/MAPPINGS/VENDORS/APPLE/Readme.txt * * to get an idea how to do that. Basically, if the language ID * is~0, don't use it, otherwise subtract 1 from the language ID. * Then examine `encoding_id'. If, for example, `encoding_id' is * `TT_MAC_ID_ROMAN' and the language ID (minus~1) is * `TT_MAC_LANGID_GREEK', it is the Greek encoding, not Roman. * `TT_MAC_ID_ARABIC' with `TT_MAC_LANGID_FARSI' means the Farsi * variant the Arabic encoding. */ typedef enum FT_Encoding_ { FT_ENC_TAG( FT_ENCODING_NONE, 0, 0, 0, 0 ), FT_ENC_TAG( FT_ENCODING_MS_SYMBOL, 's', 'y', 'm', 'b' ), FT_ENC_TAG( FT_ENCODING_UNICODE, 'u', 'n', 'i', 'c' ), FT_ENC_TAG( FT_ENCODING_SJIS, 's', 'j', 'i', 's' ), FT_ENC_TAG( FT_ENCODING_PRC, 'g', 'b', ' ', ' ' ), FT_ENC_TAG( FT_ENCODING_BIG5, 'b', 'i', 'g', '5' ), FT_ENC_TAG( FT_ENCODING_WANSUNG, 'w', 'a', 'n', 's' ), FT_ENC_TAG( FT_ENCODING_JOHAB, 'j', 'o', 'h', 'a' ), /* for backward compatibility */ FT_ENCODING_GB2312 = FT_ENCODING_PRC, FT_ENCODING_MS_SJIS = FT_ENCODING_SJIS, FT_ENCODING_MS_GB2312 = FT_ENCODING_PRC, FT_ENCODING_MS_BIG5 = FT_ENCODING_BIG5, FT_ENCODING_MS_WANSUNG = FT_ENCODING_WANSUNG, FT_ENCODING_MS_JOHAB = FT_ENCODING_JOHAB, FT_ENC_TAG( FT_ENCODING_ADOBE_STANDARD, 'A', 'D', 'O', 'B' ), FT_ENC_TAG( FT_ENCODING_ADOBE_EXPERT, 'A', 'D', 'B', 'E' ), FT_ENC_TAG( FT_ENCODING_ADOBE_CUSTOM, 'A', 'D', 'B', 'C' ), FT_ENC_TAG( FT_ENCODING_ADOBE_LATIN_1, 'l', 'a', 't', '1' ), FT_ENC_TAG( FT_ENCODING_OLD_LATIN_2, 'l', 'a', 't', '2' ), FT_ENC_TAG( FT_ENCODING_APPLE_ROMAN, 'a', 'r', 'm', 'n' ) } FT_Encoding; /* these constants are deprecated; use the corresponding `FT_Encoding' */ /* values instead */ #define ft_encoding_none FT_ENCODING_NONE #define ft_encoding_unicode FT_ENCODING_UNICODE #define ft_encoding_symbol FT_ENCODING_MS_SYMBOL #define ft_encoding_latin_1 FT_ENCODING_ADOBE_LATIN_1 #define ft_encoding_latin_2 FT_ENCODING_OLD_LATIN_2 #define ft_encoding_sjis FT_ENCODING_SJIS #define ft_encoding_gb2312 FT_ENCODING_PRC #define ft_encoding_big5 FT_ENCODING_BIG5 #define ft_encoding_wansung FT_ENCODING_WANSUNG #define ft_encoding_johab FT_ENCODING_JOHAB #define ft_encoding_adobe_standard FT_ENCODING_ADOBE_STANDARD #define ft_encoding_adobe_expert FT_ENCODING_ADOBE_EXPERT #define ft_encoding_adobe_custom FT_ENCODING_ADOBE_CUSTOM #define ft_encoding_apple_roman FT_ENCODING_APPLE_ROMAN /************************************************************************** * * @struct: * FT_CharMapRec * * @description: * The base charmap structure. * * @fields: * face :: * A handle to the parent face object. * * encoding :: * An @FT_Encoding tag identifying the charmap. Use * this with @FT_Select_Charmap. * * platform_id :: * An ID number describing the platform for the * following encoding ID. This comes directly from * the TrueType specification and gets emulated for * other formats. * * encoding_id :: * A platform-specific encoding number. This also comes from the * TrueType specification and gets emulated similarly. */ typedef struct FT_CharMapRec_ { FT_Face face; FT_Encoding encoding; FT_UShort platform_id; FT_UShort encoding_id; } FT_CharMapRec; /*************************************************************************/ /*************************************************************************/ /* */ /* B A S E O B J E C T C L A S S E S */ /* */ /*************************************************************************/ /*************************************************************************/ /************************************************************************** * * @type: * FT_Face_Internal * * @description: * An opaque handle to an `FT_Face_InternalRec' structure that models * the private data of a given @FT_Face object. * * This structure might change between releases of FreeType~2 and is * not generally available to client applications. */ typedef struct FT_Face_InternalRec_* FT_Face_Internal; /************************************************************************** * * @struct: * FT_FaceRec * * @description: * FreeType root face class structure. A face object models a * typeface in a font file. * * @fields: * num_faces :: * The number of faces in the font file. Some * font formats can have multiple faces in * a single font file. * * face_index :: * This field holds two different values. * Bits 0-15 are the index of the face in the * font file (starting with value~0). They * are set to~0 if there is only one face in * the font file. * * [Since 2.6.1] Bits 16-30 are relevant to GX * and OpenType variation fonts only, holding * the named instance index for the current * face index (starting with value~1; value~0 * indicates font access without a named * instance). For non-variation fonts, bits * 16-30 are ignored. If we have the third * named instance of face~4, say, `face_index' * is set to 0x00030004. * * Bit 31 is always zero (this is, * `face_index' is always a positive value). * * [Since 2.9] Changing the design coordinates * with @FT_Set_Var_Design_Coordinates or * @FT_Set_Var_Blend_Coordinates does not * influence the named instance index value * (only @FT_Set_Named_Instance does that). * * face_flags :: * A set of bit flags that give important * information about the face; see * @FT_FACE_FLAG_XXX for the details. * * style_flags :: * The lower 16~bits contain a set of bit * flags indicating the style of the face; see * @FT_STYLE_FLAG_XXX for the details. * * [Since 2.6.1] Bits 16-30 hold the number * of named instances available for the * current face if we have a GX or OpenType * variation (sub)font. Bit 31 is always zero * (this is, `style_flags' is always a * positive value). Note that a variation * font has always at least one named * instance, namely the default instance. * * num_glyphs :: * The number of glyphs in the face. If the * face is scalable and has sbits (see * `num_fixed_sizes'), it is set to the number * of outline glyphs. * * For CID-keyed fonts (not in an SFNT * wrapper) this value gives the highest CID * used in the font. * * family_name :: * The face's family name. This is an ASCII string, usually in * English, that describes the typeface's family (like `Times New * Roman', `Bodoni', `Garamond', etc). This is a least common * denominator used to list fonts. Some formats (TrueType & OpenType) * provide localized and Unicode versions of this string. * Applications should use the format-specific interface to access * them. Can be NULL (e.g., in fonts embedded in a PDF file). * * In case the font doesn't provide a specific * family name entry, FreeType tries to * synthesize one, deriving it from other name * entries. * * style_name :: * The face's style name. This is an ASCII string, usually in * English, that describes the typeface's style (like `Italic', * `Bold', `Condensed', etc). Not all font formats provide a style * name, so this field is optional, and can be set to NULL. As for * `family_name', some formats provide localized and Unicode versions * of this string. Applications should use the format-specific * interface to access them. * * num_fixed_sizes :: * The number of bitmap strikes in the face. * Even if the face is scalable, there might * still be bitmap strikes, which are called * `sbits' in that case. * * available_sizes :: * An array of @FT_Bitmap_Size for all bitmap * strikes in the face. It is set to NULL if * there is no bitmap strike. * * Note that FreeType tries to sanitize the * strike data since they are sometimes sloppy * or incorrect, but this can easily fail. * * num_charmaps :: * The number of charmaps in the face. * * charmaps :: * An array of the charmaps of the face. * * generic :: * A field reserved for client uses. See the * @FT_Generic type description. * * bbox :: * The font bounding box. Coordinates are * expressed in font units (see * `units_per_EM'). The box is large enough * to contain any glyph from the font. Thus, * `bbox.yMax' can be seen as the `maximum * ascender', and `bbox.yMin' as the `minimum * descender'. Only relevant for scalable * formats. * * Note that the bounding box might be off by * (at least) one pixel for hinted fonts. See * @FT_Size_Metrics for further discussion. * * units_per_EM :: * The number of font units per EM square for * this face. This is typically 2048 for * TrueType fonts, and 1000 for Type~1 fonts. * Only relevant for scalable formats. * * ascender :: * The typographic ascender of the face, * expressed in font units. For font formats * not having this information, it is set to * `bbox.yMax'. Only relevant for scalable * formats. * * descender :: * The typographic descender of the face, * expressed in font units. For font formats * not having this information, it is set to * `bbox.yMin'. Note that this field is * negative for values below the baseline. * Only relevant for scalable formats. * * height :: * This value is the vertical distance * between two consecutive baselines, * expressed in font units. It is always * positive. Only relevant for scalable * formats. * * If you want the global glyph height, use * `ascender - descender'. * * max_advance_width :: * The maximum advance width, in font units, * for all glyphs in this face. This can be * used to make word wrapping computations * faster. Only relevant for scalable * formats. * * max_advance_height :: * The maximum advance height, in font units, * for all glyphs in this face. This is only * relevant for vertical layouts, and is set * to `height' for fonts that do not provide * vertical metrics. Only relevant for * scalable formats. * * underline_position :: * The position, in font units, of the * underline line for this face. It is the * center of the underlining stem. Only * relevant for scalable formats. * * underline_thickness :: * The thickness, in font units, of the * underline for this face. Only relevant for * scalable formats. * * glyph :: * The face's associated glyph slot(s). * * size :: * The current active size for this face. * * charmap :: * The current active charmap for this face. * * @note: * Fields may be changed after a call to @FT_Attach_File or * @FT_Attach_Stream. * * 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', `height', `underline_position', and * `underline_thickness'. * * Especially for TrueType fonts see also the documentation for * @FT_Size_Metrics. */ typedef struct FT_FaceRec_ { FT_Long num_faces; FT_Long face_index; FT_Long face_flags; FT_Long style_flags; FT_Long num_glyphs; FT_String* family_name; FT_String* style_name; FT_Int num_fixed_sizes; FT_Bitmap_Size* available_sizes; FT_Int num_charmaps; FT_CharMap* charmaps; FT_Generic generic; /*# The following member variables (down to `underline_thickness') */ /*# are only relevant to scalable outlines; cf. @FT_Bitmap_Size */ /*# for bitmap fonts. */ FT_BBox bbox; FT_UShort units_per_EM; FT_Short ascender; FT_Short descender; FT_Short height; FT_Short max_advance_width; FT_Short max_advance_height; FT_Short underline_position; FT_Short underline_thickness; FT_GlyphSlot glyph; FT_Size size; FT_CharMap charmap; /*@private begin */ FT_Driver driver; FT_Memory memory; FT_Stream stream; FT_ListRec sizes_list; FT_Generic autohint; /* face-specific auto-hinter data */ void* extensions; /* unused */ FT_Face_Internal internal; /*@private end */ } FT_FaceRec; /************************************************************************** * * @enum: * FT_FACE_FLAG_XXX * * @description: * A list of bit flags used in the `face_flags' field of the * @FT_FaceRec structure. They inform client applications of * properties of the corresponding face. * * @values: * FT_FACE_FLAG_SCALABLE :: * The face contains outline glyphs. Note that a face can contain * bitmap strikes also, i.e., a face can have both this flag and * @FT_FACE_FLAG_FIXED_SIZES set. * * FT_FACE_FLAG_FIXED_SIZES :: * The face contains bitmap strikes. See also the * `num_fixed_sizes' and `available_sizes' fields of @FT_FaceRec. * * FT_FACE_FLAG_FIXED_WIDTH :: * The face contains fixed-width characters (like Courier, Lucida, * MonoType, etc.). * * FT_FACE_FLAG_SFNT :: * The face uses the SFNT storage scheme. For now, this means * TrueType and OpenType. * * FT_FACE_FLAG_HORIZONTAL :: * The face contains horizontal glyph metrics. This should be set * for all common formats. * * FT_FACE_FLAG_VERTICAL :: * The face contains vertical glyph metrics. This is only * available in some formats, not all of them. * * FT_FACE_FLAG_KERNING :: * The face contains kerning information. If set, the kerning * distance can be retrieved using the function @FT_Get_Kerning. * Otherwise the function always return the vector (0,0). Note * that FreeType doesn't handle kerning data from the SFNT `GPOS' * table (as present in many OpenType fonts). * * FT_FACE_FLAG_FAST_GLYPHS :: * THIS FLAG IS DEPRECATED. DO NOT USE OR TEST IT. * * FT_FACE_FLAG_MULTIPLE_MASTERS :: * The face contains multiple masters and is capable of * interpolating between them. Supported formats are Adobe MM, * TrueType GX, and OpenType variation fonts. * * See section @multiple_masters for API details. * * FT_FACE_FLAG_GLYPH_NAMES :: * The face contains glyph names, which can be retrieved using * @FT_Get_Glyph_Name. Note that some TrueType fonts contain * broken glyph name tables. Use the function * @FT_Has_PS_Glyph_Names when needed. * * FT_FACE_FLAG_EXTERNAL_STREAM :: * Used internally by FreeType to indicate that a face's stream was * provided by the client application and should not be destroyed * when @FT_Done_Face is called. Don't read or test this flag. * * FT_FACE_FLAG_HINTER :: * The font driver has a hinting machine of its own. For example, * with TrueType fonts, it makes sense to use data from the SFNT * `gasp' table only if the native TrueType hinting engine (with * the bytecode interpreter) is available and active. * * FT_FACE_FLAG_CID_KEYED :: * The face is CID-keyed. In that case, the face is not accessed * by glyph indices but by CID values. For subsetted CID-keyed * fonts this has the consequence that not all index values are a * valid argument to @FT_Load_Glyph. Only the CID values for which * corresponding glyphs in the subsetted font exist make * `FT_Load_Glyph' return successfully; in all other cases you get * an `FT_Err_Invalid_Argument' error. * * Note that CID-keyed fonts that are in an SFNT wrapper (this is, * all OpenType/CFF fonts) don't have this flag set since the * glyphs are accessed in the normal way (using contiguous * indices); the `CID-ness' isn't visible to the application. * * FT_FACE_FLAG_TRICKY :: * The face is `tricky', this is, it always needs the font format's * native hinting engine to get a reasonable result. A typical * example is the old Chinese font `mingli.ttf' (but not * `mingliu.ttc') that uses TrueType bytecode instructions to move * and scale all of its subglyphs. * * It is not possible to auto-hint such fonts using * @FT_LOAD_FORCE_AUTOHINT; it will also ignore * @FT_LOAD_NO_HINTING. You have to set both @FT_LOAD_NO_HINTING * and @FT_LOAD_NO_AUTOHINT to really disable hinting; however, you * probably never want this except for demonstration purposes. * * Currently, there are about a dozen TrueType fonts in the list of * tricky fonts; they are hard-coded in file `ttobjs.c'. * * FT_FACE_FLAG_COLOR :: * [Since 2.5.1] The face has color glyph tables. See * @FT_LOAD_COLOR for more information. * * FT_FACE_FLAG_VARIATION :: * [Since 2.9] Set if the current face (or named instance) has been * altered with @FT_Set_MM_Design_Coordinates, * @FT_Set_Var_Design_Coordinates, or * @FT_Set_Var_Blend_Coordinates. This flag is unset by a call to * @FT_Set_Named_Instance. */ #define FT_FACE_FLAG_SCALABLE ( 1L << 0 ) #define FT_FACE_FLAG_FIXED_SIZES ( 1L << 1 ) #define FT_FACE_FLAG_FIXED_WIDTH ( 1L << 2 ) #define FT_FACE_FLAG_SFNT ( 1L << 3 ) #define FT_FACE_FLAG_HORIZONTAL ( 1L << 4 ) #define FT_FACE_FLAG_VERTICAL ( 1L << 5 ) #define FT_FACE_FLAG_KERNING ( 1L << 6 ) #define FT_FACE_FLAG_FAST_GLYPHS ( 1L << 7 ) #define FT_FACE_FLAG_MULTIPLE_MASTERS ( 1L << 8 ) #define FT_FACE_FLAG_GLYPH_NAMES ( 1L << 9 ) #define FT_FACE_FLAG_EXTERNAL_STREAM ( 1L << 10 ) #define FT_FACE_FLAG_HINTER ( 1L << 11 ) #define FT_FACE_FLAG_CID_KEYED ( 1L << 12 ) #define FT_FACE_FLAG_TRICKY ( 1L << 13 ) #define FT_FACE_FLAG_COLOR ( 1L << 14 ) #define FT_FACE_FLAG_VARIATION ( 1L << 15 ) /************************************************************************* * * @macro: * FT_HAS_HORIZONTAL * * @description: * A macro that returns true whenever a face object contains * horizontal metrics (this is true for all font formats though). * * @also: * @FT_HAS_VERTICAL can be used to check for vertical metrics. * */ #define FT_HAS_HORIZONTAL( face ) \ ( (face)->face_flags & FT_FACE_FLAG_HORIZONTAL ) /************************************************************************* * * @macro: * FT_HAS_VERTICAL * * @description: * A macro that returns true whenever a face object contains real * vertical metrics (and not only synthesized ones). * */ #define FT_HAS_VERTICAL( face ) \ ( (face)->face_flags & FT_FACE_FLAG_VERTICAL ) /************************************************************************* * * @macro: * FT_HAS_KERNING * * @description: * A macro that returns true whenever a face object contains kerning * data that can be accessed with @FT_Get_Kerning. * */ #define FT_HAS_KERNING( face ) \ ( (face)->face_flags & FT_FACE_FLAG_KERNING ) /************************************************************************* * * @macro: * FT_IS_SCALABLE * * @description: * A macro that returns true whenever a face object contains a scalable * font face (true for TrueType, Type~1, Type~42, CID, OpenType/CFF, * and PFR font formats). * */ #define FT_IS_SCALABLE( face ) \ ( (face)->face_flags & FT_FACE_FLAG_SCALABLE ) /************************************************************************* * * @macro: * FT_IS_SFNT * * @description: * A macro that returns true whenever a face object contains a font * whose format is based on the SFNT storage scheme. This usually * means: TrueType fonts, OpenType fonts, as well as SFNT-based embedded * bitmap fonts. * * If this macro is true, all functions defined in @FT_SFNT_NAMES_H and * @FT_TRUETYPE_TABLES_H are available. * */ #define FT_IS_SFNT( face ) \ ( (face)->face_flags & FT_FACE_FLAG_SFNT ) /************************************************************************* * * @macro: * FT_IS_FIXED_WIDTH * * @description: * A macro that returns true whenever a face object contains a font face * that contains fixed-width (or `monospace', `fixed-pitch', etc.) * glyphs. * */ #define FT_IS_FIXED_WIDTH( face ) \ ( (face)->face_flags & FT_FACE_FLAG_FIXED_WIDTH ) /************************************************************************* * * @macro: * FT_HAS_FIXED_SIZES * * @description: * A macro that returns true whenever a face object contains some * embedded bitmaps. See the `available_sizes' field of the * @FT_FaceRec structure. * */ #define FT_HAS_FIXED_SIZES( face ) \ ( (face)->face_flags & FT_FACE_FLAG_FIXED_SIZES ) /************************************************************************* * * @macro: * FT_HAS_FAST_GLYPHS * * @description: * Deprecated. * */ #define FT_HAS_FAST_GLYPHS( face ) 0 /************************************************************************* * * @macro: * FT_HAS_GLYPH_NAMES * * @description: * A macro that returns true whenever a face object contains some glyph * names that can be accessed through @FT_Get_Glyph_Name. * */ #define FT_HAS_GLYPH_NAMES( face ) \ ( (face)->face_flags & FT_FACE_FLAG_GLYPH_NAMES ) /************************************************************************* * * @macro: * FT_HAS_MULTIPLE_MASTERS * * @description: * A macro that returns true whenever a face object contains some * multiple masters. The functions provided by @FT_MULTIPLE_MASTERS_H * are then available to choose the exact design you want. * */ #define FT_HAS_MULTIPLE_MASTERS( face ) \ ( (face)->face_flags & FT_FACE_FLAG_MULTIPLE_MASTERS ) /************************************************************************* * * @macro: * FT_IS_NAMED_INSTANCE * * @description: * A macro that returns true whenever a face object is a named instance * of a GX or OpenType variation font. * * [Since 2.9] Changing the design coordinates with * @FT_Set_Var_Design_Coordinates or @FT_Set_Var_Blend_Coordinates does * not influence the return value of this macro (only * @FT_Set_Named_Instance does that). * * @since: * 2.7 * */ #define FT_IS_NAMED_INSTANCE( face ) \ ( (face)->face_index & 0x7FFF0000L ) /************************************************************************* * * @macro: * FT_IS_VARIATION * * @description: * A macro that returns true whenever a face object has been altered * by @FT_Set_MM_Design_Coordinates, @FT_Set_Var_Design_Coordinates, or * @FT_Set_Var_Blend_Coordinates. * * @since: * 2.9 * */ #define FT_IS_VARIATION( face ) \ ( (face)->face_flags & FT_FACE_FLAG_VARIATION ) /************************************************************************* * * @macro: * FT_IS_CID_KEYED * * @description: * A macro that returns true whenever a face object contains a CID-keyed * font. See the discussion of @FT_FACE_FLAG_CID_KEYED for more * details. * * If this macro is true, all functions defined in @FT_CID_H are * available. * */ #define FT_IS_CID_KEYED( face ) \ ( (face)->face_flags & FT_FACE_FLAG_CID_KEYED ) /************************************************************************* * * @macro: * FT_IS_TRICKY * * @description: * A macro that returns true whenever a face represents a `tricky' font. * See the discussion of @FT_FACE_FLAG_TRICKY for more details. * */ #define FT_IS_TRICKY( face ) \ ( (face)->face_flags & FT_FACE_FLAG_TRICKY ) /************************************************************************* * * @macro: * FT_HAS_COLOR * * @description: * A macro that returns true whenever a face object contains * tables for color glyphs. * * @since: * 2.5.1 * */ #define FT_HAS_COLOR( face ) \ ( (face)->face_flags & FT_FACE_FLAG_COLOR ) /************************************************************************** * * @enum: * FT_STYLE_FLAG_XXX * * @description: * A list of bit flags to indicate the style of a given face. These * are used in the `style_flags' field of @FT_FaceRec. * * @values: * FT_STYLE_FLAG_ITALIC :: * The face style is italic or oblique. * * FT_STYLE_FLAG_BOLD :: * The face is bold. * * @note: * The style information as provided by FreeType is very basic. More * details are beyond the scope and should be done on a higher level * (for example, by analyzing various fields of the `OS/2' table in * SFNT based fonts). */ #define FT_STYLE_FLAG_ITALIC ( 1 << 0 ) #define FT_STYLE_FLAG_BOLD ( 1 << 1 ) /************************************************************************** * * @type: * FT_Size_Internal * * @description: * An opaque handle to an `FT_Size_InternalRec' structure, used to * model private data of a given @FT_Size object. */ typedef struct FT_Size_InternalRec_* FT_Size_Internal; /************************************************************************** * * @struct: * FT_Size_Metrics * * @description: * The size metrics structure gives the metrics of a size object. * * @fields: * x_ppem :: * The width of the scaled EM square in pixels, hence * the term `ppem' (pixels per EM). It is also * referred to as `nominal width'. * * y_ppem :: * The height of the scaled EM square in pixels, * hence the term `ppem' (pixels per EM). It is also * referred to as `nominal height'. * * x_scale :: * A 16.16 fractional scaling value to convert * horizontal metrics from font units to 26.6 * fractional pixels. Only relevant for scalable * font formats. * * y_scale :: * A 16.16 fractional scaling value to convert * vertical metrics from font units to 26.6 * fractional pixels. Only relevant for scalable * font formats. * * ascender :: * The ascender in 26.6 fractional pixels, rounded up * to an integer value. See @FT_FaceRec for the * details. * * descender :: * The descender in 26.6 fractional pixels, rounded * down to an integer value. See @FT_FaceRec for the * details. * * height :: * The height in 26.6 fractional pixels, rounded to * an integer value. See @FT_FaceRec for the * details. * * max_advance :: * The maximum advance width in 26.6 fractional * pixels, rounded to an integer value. See * @FT_FaceRec for the details. * * @note: * The scaling values, if relevant, are determined first during a * size changing operation. The remaining fields are then set by the * driver. For scalable formats, they are usually set to scaled * values of the corresponding fields in @FT_FaceRec. Some values * like ascender or descender are rounded for historical reasons; * more precise values (for outline fonts) can be derived by scaling * the corresponding @FT_FaceRec values manually, with code similar * to the following. * * { * scaled_ascender = FT_MulFix( face->ascender, * size_metrics->y_scale ); * } * * Note that due to glyph hinting and the selected rendering mode * these values are usually not exact; consequently, they must be * treated as unreliable with an error margin of at least one pixel! * * Indeed, the only way to get the exact metrics is to render _all_ * glyphs. As this would be a definite performance hit, it is up to * client applications to perform such computations. * * The `FT_Size_Metrics' structure is valid for bitmap fonts also. * * * *TrueType* *fonts* *with* *native* *bytecode* *hinting* * * All applications that handle TrueType fonts with native hinting * must be aware that TTFs expect different rounding of vertical font * dimensions. The application has to cater for this, especially if * it wants to rely on a TTF's vertical data (for example, to * properly align box characters vertically). * * Only the application knows _in_ _advance_ that it is going to use * native hinting for TTFs! FreeType, on the other hand, selects the * hinting mode not at the time of creating an @FT_Size object but * much later, namely while calling @FT_Load_Glyph. * * Here is some pseudo code that illustrates a possible solution. * * { * font_format = FT_Get_Font_Format( face ); * * if ( !strcmp( font_format, "TrueType" ) && * do_native_bytecode_hinting ) * { * ascender = ROUND( FT_MulFix( face->ascender, * size_metrics->y_scale ) ); * descender = ROUND( FT_MulFix( face->descender, * size_metrics->y_scale ) ); * } * else * { * ascender = size_metrics->ascender; * descender = size_metrics->descender; * } * * height = size_metrics->height; * max_advance = size_metrics->max_advance; * } */ typedef struct FT_Size_Metrics_ { FT_UShort x_ppem; /* horizontal pixels per EM */ FT_UShort y_ppem; /* vertical pixels per EM */ FT_Fixed x_scale; /* scaling values used to convert font */ FT_Fixed y_scale; /* units to 26.6 fractional pixels */ FT_Pos ascender; /* ascender in 26.6 frac. pixels */ FT_Pos descender; /* descender in 26.6 frac. pixels */ FT_Pos height; /* text height in 26.6 frac. pixels */ FT_Pos max_advance; /* max horizontal advance, in 26.6 pixels */ } FT_Size_Metrics; /************************************************************************** * * @struct: * FT_SizeRec * * @description: * FreeType root size class structure. A size object models a face * object at a given size. * * @fields: * face :: * Handle to the parent face object. * * generic :: * A typeless pointer, unused by the FreeType library or * any of its drivers. It can be used by client * applications to link their own data to each size * object. * * metrics :: * Metrics for this size object. This field is read-only. */ typedef struct FT_SizeRec_ { FT_Face face; /* parent face object */ FT_Generic generic; /* generic pointer for client uses */ FT_Size_Metrics metrics; /* size metrics */ FT_Size_Internal internal; } FT_SizeRec; /************************************************************************** * * @struct: * FT_SubGlyph * * @description: * The subglyph structure is an internal object used to describe * subglyphs (for example, in the case of composites). * * @note: * The subglyph implementation is not part of the high-level API, * hence the forward structure declaration. * * You can however retrieve subglyph information with * @FT_Get_SubGlyph_Info. */ typedef struct FT_SubGlyphRec_* FT_SubGlyph; /************************************************************************** * * @type: * FT_Slot_Internal * * @description: * An opaque handle to an `FT_Slot_InternalRec' structure, used to * model private data of a given @FT_GlyphSlot object. */ typedef struct FT_Slot_InternalRec_* FT_Slot_Internal; /************************************************************************** * * @struct: * FT_GlyphSlotRec * * @description: * FreeType root glyph slot class structure. A glyph slot is a * container where individual glyphs can be loaded, be they in * outline or bitmap format. * * @fields: * library :: * A handle to the FreeType library instance * this slot belongs to. * * face :: * A handle to the parent face object. * * next :: * In some cases (like some font tools), several * glyph slots per face object can be a good * thing. As this is rare, the glyph slots are * listed through a direct, single-linked list * using its `next' field. * * glyph_index :: * The glyph index passed as an argument to @FT_Load_Glyph while * initializeing the glyph slot (since FreeType version 2.10). * * generic :: * A typeless pointer unused by the FreeType * library or any of its drivers. It can be * used by client applications to link their own * data to each glyph slot object. * * metrics :: * The metrics of the last loaded glyph in the * slot. The returned values depend on the last * load flags (see the @FT_Load_Glyph API * function) and can be expressed either in 26.6 * fractional pixels or font units. * * Note that even when the glyph image is * transformed, the metrics are not. * * linearHoriAdvance :: * The advance width of the unhinted glyph. * Its value is expressed in 16.16 fractional * pixels, unless @FT_LOAD_LINEAR_DESIGN is set * when loading the glyph. This field can be * important to perform correct WYSIWYG layout. * Only relevant for outline glyphs. * * linearVertAdvance :: * The advance height of the unhinted glyph. * Its value is expressed in 16.16 fractional * pixels, unless @FT_LOAD_LINEAR_DESIGN is set * when loading the glyph. This field can be * important to perform correct WYSIWYG layout. * Only relevant for outline glyphs. * * advance :: * This shorthand is, depending on * @FT_LOAD_IGNORE_TRANSFORM, the transformed * (hinted) advance width for the glyph, in 26.6 * fractional pixel format. As specified with * @FT_LOAD_VERTICAL_LAYOUT, it uses either the * `horiAdvance' or the `vertAdvance' value of * `metrics' field. * * format :: * This field indicates the format of the image * contained in the glyph slot. Typically * @FT_GLYPH_FORMAT_BITMAP, * @FT_GLYPH_FORMAT_OUTLINE, or * @FT_GLYPH_FORMAT_COMPOSITE, but other values * are possible. * * bitmap :: * This field is used as a bitmap descriptor. * Note that the address and content of the * bitmap buffer can change between calls of * @FT_Load_Glyph and a few other functions. * * bitmap_left :: * The bitmap's left bearing expressed in * integer pixels. * * bitmap_top :: * The bitmap's top bearing expressed in integer * pixels. This is the distance from the * baseline to the top-most glyph scanline, * upwards y~coordinates being *positive*. * * outline :: * The outline descriptor for the current glyph * image if its format is * @FT_GLYPH_FORMAT_OUTLINE. Once a glyph is * loaded, `outline' can be transformed, * distorted, emboldened, etc. However, it must * not be freed. * * num_subglyphs :: * The number of subglyphs in a composite glyph. * This field is only valid for the composite * glyph format that should normally only be * loaded with the @FT_LOAD_NO_RECURSE flag. * * subglyphs :: * An array of subglyph descriptors for * composite glyphs. There are `num_subglyphs' * elements in there. Currently internal to * FreeType. * * control_data :: * Certain font drivers can also return the * control data for a given glyph image (e.g. * TrueType bytecode, Type~1 charstrings, etc.). * This field is a pointer to such data; it is * currently internal to FreeType. * * control_len :: * This is the length in bytes of the control * data. Currently internal to FreeType. * * other :: * Reserved. * * lsb_delta :: * The difference between hinted and unhinted * left side bearing while auto-hinting is * active. Zero otherwise. * * rsb_delta :: * The difference between hinted and unhinted * right side bearing while auto-hinting is * active. Zero otherwise. * * @note: * If @FT_Load_Glyph is called with default flags (see * @FT_LOAD_DEFAULT) the glyph image is loaded in the glyph slot in * its native format (e.g., an outline glyph for TrueType and Type~1 * formats). [Since 2.9] The prospective bitmap metrics are * calculated according to @FT_LOAD_TARGET_XXX and other flags even * for the outline glyph, even if @FT_LOAD_RENDER is not set. * * This image can later be converted into a bitmap by calling * @FT_Render_Glyph. This function searches the current renderer for * the native image's format, then invokes it. * * The renderer is in charge of transforming the native image through * the slot's face transformation fields, then converting it into a * bitmap that is returned in `slot->bitmap'. * * Note that `slot->bitmap_left' and `slot->bitmap_top' are also used * to specify the position of the bitmap relative to the current pen * position (e.g., coordinates (0,0) on the baseline). Of course, * `slot->format' is also changed to @FT_GLYPH_FORMAT_BITMAP. * * Here is a small pseudo code fragment that shows how to use * `lsb_delta' and `rsb_delta' to do fractional positioning of * glyphs: * * { * FT_GlyphSlot slot = face->glyph; * FT_Pos origin_x = 0; * * * for all glyphs do * <load glyph with `FT_Load_Glyph'> * * FT_Outline_Translate( slot->outline, origin_x & 63, 0 ); * * <save glyph image, or render glyph, or ...> * * <compute kern between current and next glyph * and add it to `origin_x'> * * origin_x += slot->advance.x; * origin_x += slot->rsb_delta - slot->lsb_delta; * endfor * } * * Here is another small pseudo code fragment that shows how to use * `lsb_delta' and `rsb_delta' to improve integer positioning of * glyphs: * * { * FT_GlyphSlot slot = face->glyph; * FT_Pos origin_x = 0; * FT_Pos prev_rsb_delta = 0; * * * for all glyphs do * <compute kern between current and previous glyph * and add it to `origin_x'> * * <load glyph with `FT_Load_Glyph'> * * if ( prev_rsb_delta - slot->lsb_delta > 32 ) * origin_x -= 64; * else if ( prev_rsb_delta - slot->lsb_delta < -31 ) * origin_x += 64; * * prev_rsb_delta = slot->rsb_delta; * * <save glyph image, or render glyph, or ...> * * origin_x += slot->advance.x; * endfor * } * * If you use strong auto-hinting, you *must* apply these delta * values! Otherwise you will experience far too large inter-glyph * spacing at small rendering sizes in most cases. Note that it * doesn't harm to use the above code for other hinting modes also, * since the delta values are zero then. */ typedef struct FT_GlyphSlotRec_ { FT_Library library; FT_Face face; FT_GlyphSlot next; FT_UInt glyph_index; /* new in 2.10; was reserved previously */ FT_Generic generic; FT_Glyph_Metrics metrics; FT_Fixed linearHoriAdvance; FT_Fixed linearVertAdvance; FT_Vector advance; FT_Glyph_Format format; FT_Bitmap bitmap; FT_Int bitmap_left; FT_Int bitmap_top; FT_Outline outline; FT_UInt num_subglyphs; FT_SubGlyph subglyphs; void* control_data; long control_len; FT_Pos lsb_delta; FT_Pos rsb_delta; void* other; FT_Slot_Internal internal; } FT_GlyphSlotRec; /*************************************************************************/ /*************************************************************************/ /* */ /* F U N C T I O N S */ /* */ /*************************************************************************/ /*************************************************************************/ /************************************************************************** * * @function: * FT_Init_FreeType * * @description: * Initialize a new FreeType library object. The set of modules * that are registered by this function is determined at build time. * * @output: * alibrary :: * A handle to a new library object. * * @return: * FreeType error code. 0~means success. * * @note: * In case you want to provide your own memory allocating routines, * use @FT_New_Library instead, followed by a call to * @FT_Add_Default_Modules (or a series of calls to @FT_Add_Module) * and @FT_Set_Default_Properties. * * See the documentation of @FT_Library and @FT_Face for * multi-threading issues. * * If you need reference-counting (cf. @FT_Reference_Library), use * @FT_New_Library and @FT_Done_Library. * * If compilation option FT_CONFIG_OPTION_ENVIRONMENT_PROPERTIES is * set, this function reads the `FREETYPE_PROPERTIES' environment * variable to control driver properties. See section @properties * for more. */ FT_EXPORT( FT_Error ) FT_Init_FreeType( FT_Library *alibrary ); /************************************************************************** * * @function: * FT_Done_FreeType * * @description: * Destroy a given FreeType library object and all of its children, * including resources, drivers, faces, sizes, etc. * * @input: * library :: * A handle to the target library object. * * @return: * FreeType error code. 0~means success. */ FT_EXPORT( FT_Error ) FT_Done_FreeType( FT_Library library ); /************************************************************************** * * @enum: * FT_OPEN_XXX * * @description: * A list of bit field constants used within the `flags' field of the * @FT_Open_Args structure. * * @values: * FT_OPEN_MEMORY :: * This is a memory-based stream. * * FT_OPEN_STREAM :: * Copy the stream from the `stream' field. * * FT_OPEN_PATHNAME :: * Create a new input stream from a C~path * name. * * FT_OPEN_DRIVER :: * Use the `driver' field. * * FT_OPEN_PARAMS :: * Use the `num_params' and `params' fields. * * @note: * The `FT_OPEN_MEMORY', `FT_OPEN_STREAM', and `FT_OPEN_PATHNAME' * flags are mutually exclusive. */ #define FT_OPEN_MEMORY 0x1 #define FT_OPEN_STREAM 0x2 #define FT_OPEN_PATHNAME 0x4 #define FT_OPEN_DRIVER 0x8 #define FT_OPEN_PARAMS 0x10 /* these constants are deprecated; use the corresponding `FT_OPEN_XXX' */ /* values instead */ #define ft_open_memory FT_OPEN_MEMORY #define ft_open_stream FT_OPEN_STREAM #define ft_open_pathname FT_OPEN_PATHNAME #define ft_open_driver FT_OPEN_DRIVER #define ft_open_params FT_OPEN_PARAMS /************************************************************************** * * @struct: * FT_Parameter * * @description: * A simple structure to pass more or less generic parameters to * @FT_Open_Face and @FT_Face_Properties. * * @fields: * tag :: * A four-byte identification tag. * * data :: * A pointer to the parameter data. * * @note: * The ID and function of parameters are driver-specific. See * section @parameter_tags for more information. */ typedef struct FT_Parameter_ { FT_ULong tag; FT_Pointer data; } FT_Parameter; /************************************************************************** * * @struct: * FT_Open_Args * * @description: * A structure to indicate how to open a new font file or stream. A * pointer to such a structure can be used as a parameter for the * functions @FT_Open_Face and @FT_Attach_Stream. * * @fields: * flags :: * A set of bit flags indicating how to use the * structure. * * memory_base :: * The first byte of the file in memory. * * memory_size :: * The size in bytes of the file in memory. * * pathname :: * A pointer to an 8-bit file pathname. * * stream :: * A handle to a source stream object. * * driver :: * This field is exclusively used by @FT_Open_Face; * it simply specifies the font driver to use for * opening the face. If set to NULL, FreeType tries * to load the face with each one of the drivers in * its list. * * num_params :: * The number of extra parameters. * * params :: * Extra parameters passed to the font driver when * opening a new face. * * @note: * The stream type is determined by the contents of `flags' that * are tested in the following order by @FT_Open_Face: * * If the @FT_OPEN_MEMORY bit is set, assume that this is a * memory file of `memory_size' bytes, located at `memory_address'. * The data are not copied, and the client is responsible for * releasing and destroying them _after_ the corresponding call to * @FT_Done_Face. * * Otherwise, if the @FT_OPEN_STREAM bit is set, assume that a * custom input stream `stream' is used. * * Otherwise, if the @FT_OPEN_PATHNAME bit is set, assume that this * is a normal file and use `pathname' to open it. * * If the @FT_OPEN_DRIVER bit is set, @FT_Open_Face only tries to * open the file with the driver whose handler is in `driver'. * * If the @FT_OPEN_PARAMS bit is set, the parameters given by * `num_params' and `params' is used. They are ignored otherwise. * * Ideally, both the `pathname' and `params' fields should be tagged * as `const'; this is missing for API backward compatibility. In * other words, applications should treat them as read-only. */ typedef struct FT_Open_Args_ { FT_UInt flags; const FT_Byte* memory_base; FT_Long memory_size; FT_String* pathname; FT_Stream stream; FT_Module driver; FT_Int num_params; FT_Parameter* params; } FT_Open_Args; /************************************************************************** * * @function: * FT_New_Face * * @description: * Call @FT_Open_Face to open a font by its pathname. * * @inout: * library :: * A handle to the library resource. * * @input: * pathname :: * A path to the font file. * * face_index :: * See @FT_Open_Face for a detailed description of this * parameter. * * @output: * aface :: * A handle to a new face object. If `face_index' is * greater than or equal to zero, it must be non-NULL. * * @return: * FreeType error code. 0~means success. * * @note: * Use @FT_Done_Face to destroy the created @FT_Face object (along * with its slot and sizes). */ FT_EXPORT( FT_Error ) FT_New_Face( FT_Library library, const char* filepathname, FT_Long face_index, FT_Face *aface ); /************************************************************************** * * @function: * FT_New_Memory_Face * * @description: * Call @FT_Open_Face to open a font that has been loaded into * memory. * * @inout: * library :: * A handle to the library resource. * * @input: * file_base :: * A pointer to the beginning of the font data. * * file_size :: * The size of the memory chunk used by the font data. * * face_index :: * See @FT_Open_Face for a detailed description of this * parameter. * * @output: * aface :: * A handle to a new face object. If `face_index' is * greater than or equal to zero, it must be non-NULL. * * @return: * FreeType error code. 0~means success. * * @note: * You must not deallocate the memory before calling @FT_Done_Face. */ FT_EXPORT( FT_Error ) FT_New_Memory_Face( FT_Library library, const FT_Byte* file_base, FT_Long file_size, FT_Long face_index, FT_Face *aface ); /************************************************************************** * * @function: * FT_Open_Face * * @description: * Create a face object from a given resource described by * @FT_Open_Args. * * @inout: * library :: * A handle to the library resource. * * @input: * args :: * A pointer to an `FT_Open_Args' structure that must * be filled by the caller. * * face_index :: * This field holds two different values. Bits 0-15 * are the index of the face in the font file (starting * with value~0). Set it to~0 if there is only one * face in the font file. * * [Since 2.6.1] Bits 16-30 are relevant to GX and * OpenType variation fonts only, specifying the named * instance index for the current face index (starting * with value~1; value~0 makes FreeType ignore named * instances). For non-variation fonts, bits 16-30 are * ignored. Assuming that you want to access the third * named instance in face~4, `face_index' should be set * to 0x00030004. If you want to access face~4 without * variation handling, simply set `face_index' to * value~4. * * `FT_Open_Face' and its siblings can be used to * quickly check whether the font format of a given * font resource is supported by FreeType. In general, * if the `face_index' argument is negative, the * function's return value is~0 if the font format is * recognized, or non-zero otherwise. The function * allocates a more or less empty face handle in * `*aface' (if `aface' isn't NULL); the only two * useful fields in this special case are * `face->num_faces' and `face->style_flags'. For any * negative value of `face_index', `face->num_faces' * gives the number of faces within the font file. For * the negative value `-(N+1)' (with `N' a non-negative * 16-bit value), bits 16-30 in `face->style_flags' * give the number of named instances in face `N' if we * have a variation font (or zero otherwise). After * examination, the returned @FT_Face structure should * be deallocated with a call to @FT_Done_Face. * * @output: * aface :: * A handle to a new face object. If `face_index' is * greater than or equal to zero, it must be non-NULL. * * @return: * FreeType error code. 0~means success. * * @note: * Unlike FreeType 1.x, this function automatically creates a glyph * slot for the face object that can be accessed directly through * `face->glyph'. * * Each new face object created with this function also owns a * default @FT_Size object, accessible as `face->size'. * * One @FT_Library instance can have multiple face objects, this is, * @FT_Open_Face and its siblings can be called multiple times using * the same `library' argument. * * See the discussion of reference counters in the description of * @FT_Reference_Face. * * @example: * To loop over all faces, use code similar to the following snippet * (omitting the error handling). * * { * ... * FT_Face face; * FT_Long i, num_faces; * * * error = FT_Open_Face( library, args, -1, &face ); * if ( error ) { ... } * * num_faces = face->num_faces; * FT_Done_Face( face ); * * for ( i = 0; i < num_faces; i++ ) * { * ... * error = FT_Open_Face( library, args, i, &face ); * ... * FT_Done_Face( face ); * ... * } * } * * To loop over all valid values for `face_index', use something * similar to the following snippet, again without error handling. * The code accesses all faces immediately (thus only a single call * of `FT_Open_Face' within the do-loop), with and without named * instances. * * { * ... * FT_Face face; * * FT_Long num_faces = 0; * FT_Long num_instances = 0; * * FT_Long face_idx = 0; * FT_Long instance_idx = 0; * * * do * { * FT_Long id = ( instance_idx << 16 ) + face_idx; * * * error = FT_Open_Face( library, args, id, &face ); * if ( error ) { ... } * * num_faces = face->num_faces; * num_instances = face->style_flags >> 16; * * ... * * FT_Done_Face( face ); * * if ( instance_idx < num_instances ) * instance_idx++; * else * { * face_idx++; * instance_idx = 0; * } * * } while ( face_idx < num_faces ) * } */ FT_EXPORT( FT_Error ) FT_Open_Face( FT_Library library, const FT_Open_Args* args, FT_Long face_index, FT_Face *aface ); /************************************************************************** * * @function: * FT_Attach_File * * @description: * Call @FT_Attach_Stream to attach a file. * * @inout: * face :: * The target face object. * * @input: * filepathname :: * The pathname. * * @return: * FreeType error code. 0~means success. */ FT_EXPORT( FT_Error ) FT_Attach_File( FT_Face face, const char* filepathname ); /************************************************************************** * * @function: * FT_Attach_Stream * * @description: * `Attach' data to a face object. Normally, this is used to read * additional information for the face object. For example, you can * attach an AFM file that comes with a Type~1 font to get the * kerning values and other metrics. * * @inout: * face :: * The target face object. * * @input: * parameters :: * A pointer to @FT_Open_Args that must be filled by * the caller. * * @return: * FreeType error code. 0~means success. * * @note: * The meaning of the `attach' (i.e., what really happens when the * new file is read) is not fixed by FreeType itself. It really * depends on the font format (and thus the font driver). * * Client applications are expected to know what they are doing * when invoking this function. Most drivers simply do not implement * file or stream attachments. */ FT_EXPORT( FT_Error ) FT_Attach_Stream( FT_Face face, FT_Open_Args* parameters ); /************************************************************************** * * @function: * FT_Reference_Face * * @description: * A counter gets initialized to~1 at the time an @FT_Face structure * is created. This function increments the counter. @FT_Done_Face * then only destroys a face if the counter is~1, otherwise it simply * decrements the counter. * * This function helps in managing life-cycles of structures that * reference @FT_Face objects. * * @input: * face :: * A handle to a target face object. * * @return: * FreeType error code. 0~means success. * * @since: * 2.4.2 */ FT_EXPORT( FT_Error ) FT_Reference_Face( FT_Face face ); /************************************************************************** * * @function: * FT_Done_Face * * @description: * Discard a given face object, as well as all of its child slots and * sizes. * * @input: * face :: * A handle to a target face object. * * @return: * FreeType error code. 0~means success. * * @note: * See the discussion of reference counters in the description of * @FT_Reference_Face. */ FT_EXPORT( FT_Error ) FT_Done_Face( FT_Face face ); /************************************************************************** * * @function: * FT_Select_Size * * @description: * Select a bitmap strike. To be more precise, this function sets * the scaling factors of the active @FT_Size object in a face so * that bitmaps from this particular strike are taken by * @FT_Load_Glyph and friends. * * @inout: * face :: * A handle to a target face object. * * @input: * strike_index :: * The index of the bitmap strike in the * `available_sizes' field of @FT_FaceRec structure. * * @return: * FreeType error code. 0~means success. * * @note: * For bitmaps embedded in outline fonts it is common that only a * subset of the available glyphs at a given ppem value is available. * FreeType silently uses outlines if there is no bitmap for a given * glyph index. * * For GX and OpenType variation fonts, a bitmap strike makes sense * only if the default instance is active (this is, no glyph * variation takes place); otherwise, FreeType simply ignores bitmap * strikes. The same is true for all named instances that are * different from the default instance. * * Don't use this function if you are using the FreeType cache API. */ FT_EXPORT( FT_Error ) FT_Select_Size( FT_Face face, FT_Int strike_index ); /************************************************************************** * * @enum: * FT_Size_Request_Type * * @description: * An enumeration type that lists the supported size request types, * i.e., what input size (in font units) maps to the requested output * size (in pixels, as computed from the arguments of * @FT_Size_Request). * * @values: * FT_SIZE_REQUEST_TYPE_NOMINAL :: * The nominal size. The `units_per_EM' field of @FT_FaceRec is * used to determine both scaling values. * * This is the standard scaling found in most applications. In * particular, use this size request type for TrueType fonts if * they provide optical scaling or something similar. Note, * however, that `units_per_EM' is a rather abstract value which * bears no relation to the actual size of the glyphs in a font. * * FT_SIZE_REQUEST_TYPE_REAL_DIM :: * The real dimension. The sum of the `ascender' and (minus of) * the `descender' fields of @FT_FaceRec is used to determine both * scaling values. * * FT_SIZE_REQUEST_TYPE_BBOX :: * The font bounding box. The width and height of the `bbox' field * of @FT_FaceRec are used to determine the horizontal and vertical * scaling value, respectively. * * FT_SIZE_REQUEST_TYPE_CELL :: * The `max_advance_width' field of @FT_FaceRec is used to * determine the horizontal scaling value; the vertical scaling * value is determined the same way as * @FT_SIZE_REQUEST_TYPE_REAL_DIM does. Finally, both scaling * values are set to the smaller one. This type is useful if you * want to specify the font size for, say, a window of a given * dimension and 80x24 cells. * * FT_SIZE_REQUEST_TYPE_SCALES :: * Specify the scaling values directly. * * @note: * The above descriptions only apply to scalable formats. For bitmap * formats, the behaviour is up to the driver. * * See the note section of @FT_Size_Metrics if you wonder how size * requesting relates to scaling values. */ typedef enum FT_Size_Request_Type_ { FT_SIZE_REQUEST_TYPE_NOMINAL, FT_SIZE_REQUEST_TYPE_REAL_DIM, FT_SIZE_REQUEST_TYPE_BBOX, FT_SIZE_REQUEST_TYPE_CELL, FT_SIZE_REQUEST_TYPE_SCALES, FT_SIZE_REQUEST_TYPE_MAX } FT_Size_Request_Type; /************************************************************************** * * @struct: * FT_Size_RequestRec * * @description: * A structure to model a size request. * * @fields: * type :: * See @FT_Size_Request_Type. * * width :: * The desired width, given as a 26.6 fractional * point value (with 72pt = 1in). * * height :: * The desired height, given as a 26.6 fractional * point value (with 72pt = 1in). * * horiResolution :: * The horizontal resolution (dpi, i.e., pixels per * inch). If set to zero, `width' is treated as a * 26.6 fractional *pixel* value, which gets * internally rounded to an integer. * * vertResolution :: * The vertical resolution (dpi, i.e., pixels per * inch). If set to zero, `height' is treated as a * 26.6 fractional *pixel* value, which gets * internally rounded to an integer. * * @note: * If `width' is zero, the horizontal scaling value is set equal * to the vertical scaling value, and vice versa. * * If `type' is FT_SIZE_REQUEST_TYPE_SCALES, `width' and `height' are * interpreted directly as 16.16 fractional scaling values, without * any further modification, and both `horiResolution' and * `vertResolution' are ignored. */ typedef struct FT_Size_RequestRec_ { FT_Size_Request_Type type; FT_Long width; FT_Long height; FT_UInt horiResolution; FT_UInt vertResolution; } FT_Size_RequestRec; /************************************************************************** * * @struct: * FT_Size_Request * * @description: * A handle to a size request structure. */ typedef struct FT_Size_RequestRec_ *FT_Size_Request; /************************************************************************** * * @function: * FT_Request_Size * * @description: * Resize the scale of the active @FT_Size object in a face. * * @inout: * face :: * A handle to a target face object. * * @input: * req :: * A pointer to a @FT_Size_RequestRec. * * @return: * FreeType error code. 0~means success. * * @note: * Although drivers may select the bitmap strike matching the * request, you should not rely on this if you intend to select a * particular bitmap strike. Use @FT_Select_Size instead in that * case. * * The relation between the requested size and the resulting glyph * size is dependent entirely on how the size is defined in the * source face. The font designer chooses the final size of each * glyph relative to this size. For more information refer to * `https://www.freetype.org/freetype2/docs/glyphs/glyphs-2.html'. * * Contrary to @FT_Set_Char_Size, this function doesn't have special * code to normalize zero-valued widths, heights, or resolutions * (which lead to errors in most cases). * * Don't use this function if you are using the FreeType cache API. */ FT_EXPORT( FT_Error ) FT_Request_Size( FT_Face face, FT_Size_Request req ); /************************************************************************** * * @function: * FT_Set_Char_Size * * @description: * Call @FT_Request_Size to request the nominal size (in points). * * @inout: * face :: * A handle to a target face object. * * @input: * char_width :: * The nominal width, in 26.6 fractional points. * * char_height :: * The nominal height, in 26.6 fractional points. * * horz_resolution :: * The horizontal resolution in dpi. * * vert_resolution :: * The vertical resolution in dpi. * * @return: * FreeType error code. 0~means success. * * @note: * While this function allows fractional points as input values, the * resulting ppem value for the given resolution is always rounded to * the nearest integer. * * If either the character width or height is zero, it is set equal * to the other value. * * If either the horizontal or vertical resolution is zero, it is set * equal to the other value. * * A character width or height smaller than 1pt is set to 1pt; if * both resolution values are zero, they are set to 72dpi. * * Don't use this function if you are using the FreeType cache API. */ FT_EXPORT( FT_Error ) FT_Set_Char_Size( FT_Face face, FT_F26Dot6 char_width, FT_F26Dot6 char_height, FT_UInt horz_resolution, FT_UInt vert_resolution ); /************************************************************************** * * @function: * FT_Set_Pixel_Sizes * * @description: * Call @FT_Request_Size to request the nominal size (in pixels). * * @inout: * face :: * A handle to the target face object. * * @input: * pixel_width :: * The nominal width, in pixels. * * pixel_height :: * The nominal height, in pixels. * * @return: * FreeType error code. 0~means success. * * @note: * You should not rely on the resulting glyphs matching or being * constrained to this pixel size. Refer to @FT_Request_Size to * understand how requested sizes relate to actual sizes. * * Don't use this function if you are using the FreeType cache API. */ FT_EXPORT( FT_Error ) FT_Set_Pixel_Sizes( FT_Face face, FT_UInt pixel_width, FT_UInt pixel_height ); /************************************************************************** * * @function: * FT_Load_Glyph * * @description: * Load a glyph into the glyph slot of a face object. * * @inout: * face :: * A handle to the target face object where the glyph * is loaded. * * @input: * glyph_index :: * The index of the glyph in the font file. For * CID-keyed fonts (either in PS or in CFF format) * this argument specifies the CID value. * * load_flags :: * A flag indicating what to load for this glyph. The * @FT_LOAD_XXX constants can be used to control the * glyph loading process (e.g., whether the outline * should be scaled, whether to load bitmaps or not, * whether to hint the outline, etc). * * @return: * FreeType error code. 0~means success. * * @note: * The loaded glyph may be transformed. See @FT_Set_Transform for * the details. * * For subsetted CID-keyed fonts, `FT_Err_Invalid_Argument' is * returned for invalid CID values (this is, for CID values that * don't have a corresponding glyph in the font). See the discussion * of the @FT_FACE_FLAG_CID_KEYED flag for more details. * * If you receive `FT_Err_Glyph_Too_Big', try getting the glyph * outline at EM size, then scale it manually and fill it as a * graphics operation. */ FT_EXPORT( FT_Error ) FT_Load_Glyph( FT_Face face, FT_UInt glyph_index, FT_Int32 load_flags ); /************************************************************************** * * @function: * FT_Load_Char * * @description: * Load a glyph into the glyph slot of a face object, accessed by its * character code. * * @inout: * face :: * A handle to a target face object where the glyph * is loaded. * * @input: * char_code :: * The glyph's character code, according to the * current charmap used in the face. * * load_flags :: * A flag indicating what to load for this glyph. The * @FT_LOAD_XXX constants can be used to control the * glyph loading process (e.g., whether the outline * should be scaled, whether to load bitmaps or not, * whether to hint the outline, etc). * * @return: * FreeType error code. 0~means success. * * @note: * This function simply calls @FT_Get_Char_Index and @FT_Load_Glyph. * * Many fonts contain glyphs that can't be loaded by this function * since its glyph indices are not listed in any of the font's * charmaps. * * If no active cmap is set up (i.e., `face->charmap' is zero), the * call to @FT_Get_Char_Index is omitted, and the function behaves * identically to @FT_Load_Glyph. */ FT_EXPORT( FT_Error ) FT_Load_Char( FT_Face face, FT_ULong char_code, FT_Int32 load_flags ); /************************************************************************* * * @enum: * FT_LOAD_XXX * * @description: * A list of bit field constants for @FT_Load_Glyph to indicate what * kind of operations to perform during glyph loading. * * @values: * FT_LOAD_DEFAULT :: * Corresponding to~0, this value is used as the default glyph load * operation. In this case, the following happens: * * 1. FreeType looks for a bitmap for the glyph corresponding to the * face's current size. If one is found, the function returns. * The bitmap data can be accessed from the glyph slot (see note * below). * * 2. If no embedded bitmap is searched for or found, FreeType looks * for a scalable outline. If one is found, it is loaded from * the font file, scaled to device pixels, then `hinted' to the * pixel grid in order to optimize it. The outline data can be * accessed from the glyph slot (see note below). * * Note that by default the glyph loader doesn't render outlines into * bitmaps. The following flags are used to modify this default * behaviour to more specific and useful cases. * * FT_LOAD_NO_SCALE :: * Don't scale the loaded outline glyph but keep it in font units. * * This flag implies @FT_LOAD_NO_HINTING and @FT_LOAD_NO_BITMAP, and * unsets @FT_LOAD_RENDER. * * If the font is `tricky' (see @FT_FACE_FLAG_TRICKY for more), using * FT_LOAD_NO_SCALE usually yields meaningless outlines because the * subglyphs must be scaled and positioned with hinting instructions. * This can be solved by loading the font without FT_LOAD_NO_SCALE and * setting the character size to `font->units_per_EM'. * * FT_LOAD_NO_HINTING :: * Disable hinting. This generally generates `blurrier' bitmap glyphs * when the glyph are rendered in any of the anti-aliased modes. See * also the note below. * * This flag is implied by @FT_LOAD_NO_SCALE. * * FT_LOAD_RENDER :: * Call @FT_Render_Glyph after the glyph is loaded. By default, the * glyph is rendered in @FT_RENDER_MODE_NORMAL mode. This can be * overridden by @FT_LOAD_TARGET_XXX or @FT_LOAD_MONOCHROME. * * This flag is unset by @FT_LOAD_NO_SCALE. * * FT_LOAD_NO_BITMAP :: * Ignore bitmap strikes when loading. Bitmap-only fonts ignore this * flag. * * @FT_LOAD_NO_SCALE always sets this flag. * * FT_LOAD_VERTICAL_LAYOUT :: * Load the glyph for vertical text layout. In particular, the * `advance' value in the @FT_GlyphSlotRec structure is set to the * `vertAdvance' value of the `metrics' field. * * In case @FT_HAS_VERTICAL doesn't return true, you shouldn't use * this flag currently. Reason is that in this case vertical metrics * get synthesized, and those values are not always consistent across * various font formats. * * FT_LOAD_FORCE_AUTOHINT :: * Prefer the auto-hinter over the font's native hinter. See also * the note below. * * FT_LOAD_PEDANTIC :: * Make the font driver perform pedantic verifications during glyph * loading. This is mostly used to detect broken glyphs in fonts. * By default, FreeType tries to handle broken fonts also. * * In particular, errors from the TrueType bytecode engine are not * passed to the application if this flag is not set; this might * result in partially hinted or distorted glyphs in case a glyph's * bytecode is buggy. * * FT_LOAD_NO_RECURSE :: * Don't load composite glyphs recursively. Instead, the font * driver should set the `num_subglyph' and `subglyphs' values of * the glyph slot accordingly, and set `glyph->format' to * @FT_GLYPH_FORMAT_COMPOSITE. The description of subglyphs can * then be accessed with @FT_Get_SubGlyph_Info. * * This flag implies @FT_LOAD_NO_SCALE and @FT_LOAD_IGNORE_TRANSFORM. * * FT_LOAD_IGNORE_TRANSFORM :: * Ignore the transform matrix set by @FT_Set_Transform. * * FT_LOAD_MONOCHROME :: * This flag is used with @FT_LOAD_RENDER to indicate that you want to * render an outline glyph to a 1-bit monochrome bitmap glyph, with * 8~pixels packed into each byte of the bitmap data. * * Note that this has no effect on the hinting algorithm used. You * should rather use @FT_LOAD_TARGET_MONO so that the * monochrome-optimized hinting algorithm is used. * * FT_LOAD_LINEAR_DESIGN :: * Keep `linearHoriAdvance' and `linearVertAdvance' fields of * @FT_GlyphSlotRec in font units. See @FT_GlyphSlotRec for * details. * * FT_LOAD_NO_AUTOHINT :: * Disable the auto-hinter. See also the note below. * * FT_LOAD_COLOR :: * Load colored glyphs. There are slight differences depending on the * font format. * * [Since 2.5] Load embedded color bitmap images. The resulting color * bitmaps, if available, will have the @FT_PIXEL_MODE_BGRA format, * with pre-multiplied color channels. If the flag is not set and * color bitmaps are found, they are converted to 256-level gray * bitmaps, using the @FT_PIXEL_MODE_GRAY format. * * [Since 2.10] If the glyph index contains an entry in the face's * `COLR' table with a `CPAL' palette table (as defined in the * OpenType specification), make @FT_Render_Glyph provide a default * blending of the color glyph layers associated with the glyph index, * using the same bitmap format as embedded color bitmap images. This * is mainly for convenience; for full control of color layers use * @FT_Get_Color_Glyph_Layer and FreeType's color functions like * @FT_Palette_Select instead of setting FT_LOAD_COLOR for rendering * so that the client application can handle blending by itself. * * FT_LOAD_COMPUTE_METRICS :: * [Since 2.6.1] Compute glyph metrics from the glyph data, without * the use of bundled metrics tables (for example, the `hdmx' table in * TrueType fonts). This flag is mainly used by font validating or * font editing applications, which need to ignore, verify, or edit * those tables. * * Currently, this flag is only implemented for TrueType fonts. * * FT_LOAD_BITMAP_METRICS_ONLY :: * [Since 2.7.1] Request loading of the metrics and bitmap image * information of a (possibly embedded) bitmap glyph without * allocating or copying the bitmap image data itself. No effect if * the target glyph is not a bitmap image. * * This flag unsets @FT_LOAD_RENDER. * * FT_LOAD_CROP_BITMAP :: * Ignored. Deprecated. * * FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH :: * Ignored. Deprecated. * * @note: * By default, hinting is enabled and the font's native hinter (see * @FT_FACE_FLAG_HINTER) is preferred over the auto-hinter. You can * disable hinting by setting @FT_LOAD_NO_HINTING or change the * precedence by setting @FT_LOAD_FORCE_AUTOHINT. You can also set * @FT_LOAD_NO_AUTOHINT in case you don't want the auto-hinter to be * used at all. * * See the description of @FT_FACE_FLAG_TRICKY for a special exception * (affecting only a handful of Asian fonts). * * Besides deciding which hinter to use, you can also decide which * hinting algorithm to use. See @FT_LOAD_TARGET_XXX for details. * * Note that the auto-hinter needs a valid Unicode cmap (either a native * one or synthesized by FreeType) for producing correct results. If a * font provides an incorrect mapping (for example, assigning the * character code U+005A, LATIN CAPITAL LETTER Z, to a glyph depicting a * mathematical integral sign), the auto-hinter might produce useless * results. * */ #define FT_LOAD_DEFAULT 0x0 #define FT_LOAD_NO_SCALE ( 1L << 0 ) #define FT_LOAD_NO_HINTING ( 1L << 1 ) #define FT_LOAD_RENDER ( 1L << 2 ) #define FT_LOAD_NO_BITMAP ( 1L << 3 ) #define FT_LOAD_VERTICAL_LAYOUT ( 1L << 4 ) #define FT_LOAD_FORCE_AUTOHINT ( 1L << 5 ) #define FT_LOAD_CROP_BITMAP ( 1L << 6 ) #define FT_LOAD_PEDANTIC ( 1L << 7 ) #define FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH ( 1L << 9 ) #define FT_LOAD_NO_RECURSE ( 1L << 10 ) #define FT_LOAD_IGNORE_TRANSFORM ( 1L << 11 ) #define FT_LOAD_MONOCHROME ( 1L << 12 ) #define FT_LOAD_LINEAR_DESIGN ( 1L << 13 ) #define FT_LOAD_NO_AUTOHINT ( 1L << 15 ) /* Bits 16-19 are used by `FT_LOAD_TARGET_' */ #define FT_LOAD_COLOR ( 1L << 20 ) #define FT_LOAD_COMPUTE_METRICS ( 1L << 21 ) #define FT_LOAD_BITMAP_METRICS_ONLY ( 1L << 22 ) /* */ /* used internally only by certain font drivers */ #define FT_LOAD_ADVANCE_ONLY ( 1L << 8 ) #define FT_LOAD_SBITS_ONLY ( 1L << 14 ) /************************************************************************** * * @enum: * FT_LOAD_TARGET_XXX * * @description: * A list of values to select a specific hinting algorithm for the * hinter. You should OR one of these values to your `load_flags' * when calling @FT_Load_Glyph. * * Note that a font's native hinters may ignore the hinting algorithm * you have specified (e.g., the TrueType bytecode interpreter). You * can set @FT_LOAD_FORCE_AUTOHINT to ensure that the auto-hinter is * used. * * @values: * FT_LOAD_TARGET_NORMAL :: * The default hinting algorithm, optimized for standard gray-level * rendering. For monochrome output, use @FT_LOAD_TARGET_MONO * instead. * * FT_LOAD_TARGET_LIGHT :: * A lighter hinting algorithm for gray-level modes. Many generated * glyphs are fuzzier but better resemble their original shape. This * is achieved by snapping glyphs to the pixel grid only vertically * (Y-axis), as is done by FreeType's new CFF engine or Microsoft's * ClearType font renderer. This preserves inter-glyph spacing in * horizontal text. The snapping is done either by the native font * driver, if the driver itself and the font support it, or by the * auto-hinter. * * Advance widths are rounded to integer values; however, using the * `lsb_delta' and `rsb_delta' fields of @FT_GlyphSlotRec, it is * possible to get fractional advance widths for subpixel positioning * (which is recommended to use). * * If configuration option AF_CONFIG_OPTION_TT_SIZE_METRICS is active, * TrueType-like metrics are used to make this mode behave similarly * as in unpatched FreeType versions between 2.4.6 and 2.7.1 * (inclusive). * * FT_LOAD_TARGET_MONO :: * Strong hinting algorithm that should only be used for monochrome * output. The result is probably unpleasant if the glyph is rendered * in non-monochrome modes. * * FT_LOAD_TARGET_LCD :: * A variant of @FT_LOAD_TARGET_LIGHT optimized for horizontally * decimated LCD displays. * * FT_LOAD_TARGET_LCD_V :: * A variant of @FT_LOAD_TARGET_NORMAL optimized for vertically * decimated LCD displays. * * @note: * You should use only _one_ of the FT_LOAD_TARGET_XXX values in your * `load_flags'. They can't be ORed. * * If @FT_LOAD_RENDER is also set, the glyph is rendered in the * corresponding mode (i.e., the mode that matches the used algorithm * best). An exception is FT_LOAD_TARGET_MONO since it implies * @FT_LOAD_MONOCHROME. * * You can use a hinting algorithm that doesn't correspond to the same * rendering mode. As an example, it is possible to use the `light' * hinting algorithm and have the results rendered in horizontal LCD * pixel mode, with code like * * { * FT_Load_Glyph( face, glyph_index, * load_flags | FT_LOAD_TARGET_LIGHT ); * * FT_Render_Glyph( face->glyph, FT_RENDER_MODE_LCD ); * } * * In general, you should stick with one rendering mode. For example, * switching between @FT_LOAD_TARGET_NORMAL and @FT_LOAD_TARGET_MONO * enforces a lot of recomputation for TrueType fonts, which is slow. * Another reason is caching: Selecting a different mode usually causes * changes in both the outlines and the rasterized bitmaps; it is thus * necessary to empty the cache after a mode switch to avoid false hits. * */ #define FT_LOAD_TARGET_( x ) ( (FT_Int32)( (x) & 15 ) << 16 ) #define FT_LOAD_TARGET_NORMAL FT_LOAD_TARGET_( FT_RENDER_MODE_NORMAL ) #define FT_LOAD_TARGET_LIGHT FT_LOAD_TARGET_( FT_RENDER_MODE_LIGHT ) #define FT_LOAD_TARGET_MONO FT_LOAD_TARGET_( FT_RENDER_MODE_MONO ) #define FT_LOAD_TARGET_LCD FT_LOAD_TARGET_( FT_RENDER_MODE_LCD ) #define FT_LOAD_TARGET_LCD_V FT_LOAD_TARGET_( FT_RENDER_MODE_LCD_V ) /************************************************************************** * * @macro: * FT_LOAD_TARGET_MODE * * @description: * Return the @FT_Render_Mode corresponding to a given * @FT_LOAD_TARGET_XXX value. * */ #define FT_LOAD_TARGET_MODE( x ) ( (FT_Render_Mode)( ( (x) >> 16 ) & 15 ) ) /************************************************************************** * * @function: * FT_Set_Transform * * @description: * Set the transformation that is applied to glyph images when they * are loaded into a glyph slot through @FT_Load_Glyph. * * @inout: * face :: * A handle to the source face object. * * @input: * matrix :: * A pointer to the transformation's 2x2 matrix. Use NULL * for the identity matrix. * delta :: * A pointer to the translation vector. Use NULL for the * null vector. * * @note: * The transformation is only applied to scalable image formats after * the glyph has been loaded. It means that hinting is unaltered by * the transformation and is performed on the character size given in * the last call to @FT_Set_Char_Size or @FT_Set_Pixel_Sizes. * * Note that this also transforms the `face.glyph.advance' field, but * *not* the values in `face.glyph.metrics'. */ FT_EXPORT( void ) FT_Set_Transform( FT_Face face, FT_Matrix* matrix, FT_Vector* delta ); /************************************************************************** * * @enum: * FT_Render_Mode * * @description: * Render modes supported by FreeType~2. Each mode corresponds to a * specific type of scanline conversion performed on the outline. * * For bitmap fonts and embedded bitmaps the `bitmap->pixel_mode' * field in the @FT_GlyphSlotRec structure gives the format of the * returned bitmap. * * All modes except @FT_RENDER_MODE_MONO use 256 levels of opacity, * indicating pixel coverage. Use linear alpha blending and gamma * correction to correctly render non-monochrome glyph bitmaps onto a * surface; see @FT_Render_Glyph. * * @values: * FT_RENDER_MODE_NORMAL :: * Default render mode; it corresponds to 8-bit anti-aliased * bitmaps. * * FT_RENDER_MODE_LIGHT :: * This is equivalent to @FT_RENDER_MODE_NORMAL. It is only * defined as a separate value because render modes are also used * indirectly to define hinting algorithm selectors. See * @FT_LOAD_TARGET_XXX for details. * * FT_RENDER_MODE_MONO :: * This mode corresponds to 1-bit bitmaps (with 2~levels of * opacity). * * FT_RENDER_MODE_LCD :: * This mode corresponds to horizontal RGB and BGR subpixel * displays like LCD screens. It produces 8-bit bitmaps that are * 3~times the width of the original glyph outline in pixels, and * which use the @FT_PIXEL_MODE_LCD mode. * * FT_RENDER_MODE_LCD_V :: * This mode corresponds to vertical RGB and BGR subpixel displays * (like PDA screens, rotated LCD displays, etc.). It produces * 8-bit bitmaps that are 3~times the height of the original * glyph outline in pixels and use the @FT_PIXEL_MODE_LCD_V mode. * * @note: * Should you define FT_CONFIG_OPTION_SUBPIXEL_RENDERING in your * `ftoption.h', which enables patented ClearType-style rendering, * the LCD-optimized glyph bitmaps should be filtered to reduce color * fringes inherent to this technology. You can either set up LCD * filtering with @FT_Library_SetLcdFilter or @FT_Face_Properties, * or do the filtering yourself. The default FreeType LCD rendering * technology does not require filtering. * * The selected render mode only affects vector glyphs of a font. * Embedded bitmaps often have a different pixel mode like * @FT_PIXEL_MODE_MONO. You can use @FT_Bitmap_Convert to transform * them into 8-bit pixmaps. */ typedef enum FT_Render_Mode_ { FT_RENDER_MODE_NORMAL = 0, FT_RENDER_MODE_LIGHT, FT_RENDER_MODE_MONO, FT_RENDER_MODE_LCD, FT_RENDER_MODE_LCD_V, FT_RENDER_MODE_MAX } FT_Render_Mode; /* these constants are deprecated; use the corresponding */ /* `FT_Render_Mode' values instead */ #define ft_render_mode_normal FT_RENDER_MODE_NORMAL #define ft_render_mode_mono FT_RENDER_MODE_MONO /************************************************************************** * * @function: * FT_Render_Glyph * * @description: * Convert a given glyph image to a bitmap. It does so by inspecting * the glyph image format, finding the relevant renderer, and * invoking it. * * @inout: * slot :: * A handle to the glyph slot containing the image to * convert. * * @input: * render_mode :: * The render mode used to render the glyph image into * a bitmap. See @FT_Render_Mode for a list of * possible values. * * If @FT_RENDER_MODE_NORMAL is used, the flag * @FT_LOAD_COLOR can be additionally set to make the * function provide a default blending of colored * glyph layers associated with the current glyph slot * (provided the font contains such layers) instead of * rendering the glyph slot's outline. See * @FT_LOAD_COLOR for more information. * * @return: * FreeType error code. 0~means success. * * @note: * To get meaningful results, font scaling values must be set with * functions like @FT_Set_Char_Size before calling `FT_Render_Glyph'. * * When FreeType outputs a bitmap of a glyph, it really outputs an * alpha coverage map. If a pixel is completely covered by a * filled-in outline, the bitmap contains 0xFF at that pixel, meaning * that 0xFF/0xFF fraction of that pixel is covered, meaning the * pixel is 100% black (or 0% bright). If a pixel is only 50% * covered (value 0x80), the pixel is made 50% black (50% bright or a * middle shade of grey). 0% covered means 0% black (100% bright or * white). * * On high-DPI screens like on smartphones and tablets, the pixels * are so small that their chance of being completely covered and * therefore completely black are fairly good. On the low-DPI * screens, however, the situation is different. The pixels are too * large for most of the details of a glyph and shades of gray are * the norm rather than the exception. * * This is relevant because all our screens have a second problem: * they are not linear. 1~+~1 is not~2. Twice the value does not * result in twice the brightness. When a pixel is only 50% covered, * the coverage map says 50% black, and this translates to a pixel * value of 128 when you use 8~bits per channel (0-255). However, * this does not translate to 50% brightness for that pixel on our * sRGB and gamma~2.2 screens. Due to their non-linearity, they * dwell longer in the darks and only a pixel value of about 186 * results in 50% brightness -- 128 ends up too dark on both bright * and dark backgrounds. The net result is that dark text looks * burnt-out, pixely and blotchy on bright background, bright text * too frail on dark backgrounds, and colored text on colored * background (for example, red on green) seems to have dark halos or * `dirt' around it. The situation is especially ugly for diagonal * stems like in `w' glyph shapes where the quality of FreeType's * anti-aliasing depends on the correct display of grays. On * high-DPI screens where smaller, fully black pixels reign supreme, * this doesn't matter, but on our low-DPI screens with all the gray * shades, it does. 0% and 100% brightness are the same things in * linear and non-linear space, just all the shades in-between * aren't. * * The blending function for placing text over a background is * * { * dst = alpha * src + (1 - alpha) * dst , * } * * which is known as the OVER operator. * * To correctly composite an antialiased pixel of a glyph onto a * surface, * * 1. take the foreground and background colors (e.g., in sRGB space) * and apply gamma to get them in a linear space, * * 2. use OVER to blend the two linear colors using the glyph pixel * as the alpha value (remember, the glyph bitmap is an alpha * coverage bitmap), and * * 3. apply inverse gamma to the blended pixel and write it back to * the image. * * Internal testing at Adobe found that a target inverse gamma of~1.8 * for step~3 gives good results across a wide range of displays with * an sRGB gamma curve or a similar one. * * This process can cost performance. There is an approximation that * does not need to know about the background color; see * https://bel.fi/alankila/lcd/ and * https://bel.fi/alankila/lcd/alpcor.html for details. * * *ATTENTION*: Linear blending is even more important when dealing * with subpixel-rendered glyphs to prevent color-fringing! A * subpixel-rendered glyph must first be filtered with a filter that * gives equal weight to the three color primaries and does not * exceed a sum of 0x100, see section @lcd_rendering. Then the * only difference to gray linear blending is that subpixel-rendered * linear blending is done 3~times per pixel: red foreground subpixel * to red background subpixel and so on for green and blue. */ FT_EXPORT( FT_Error ) FT_Render_Glyph( FT_GlyphSlot slot, FT_Render_Mode render_mode ); /************************************************************************** * * @enum: * FT_Kerning_Mode * * @description: * An enumeration to specify the format of kerning values returned by * @FT_Get_Kerning. * * @values: * FT_KERNING_DEFAULT :: * Return grid-fitted kerning distances in * 26.6 fractional pixels. * * FT_KERNING_UNFITTED :: * Return un-grid-fitted kerning distances in * 26.6 fractional pixels. * * FT_KERNING_UNSCALED :: * Return the kerning vector in original font * units. * * @note: * FT_KERNING_DEFAULT returns full pixel values; it also makes * FreeType heuristically scale down kerning distances at small ppem * values so that they don't become too big. * * Both FT_KERNING_DEFAULT and FT_KERNING_UNFITTED use the current * horizontal scaling factor (as set e.g. with @FT_Set_Char_Size) to * convert font units to pixels. */ typedef enum FT_Kerning_Mode_ { FT_KERNING_DEFAULT = 0, FT_KERNING_UNFITTED, FT_KERNING_UNSCALED } FT_Kerning_Mode; /* these constants are deprecated; use the corresponding */ /* `FT_Kerning_Mode' values instead */ #define ft_kerning_default FT_KERNING_DEFAULT #define ft_kerning_unfitted FT_KERNING_UNFITTED #define ft_kerning_unscaled FT_KERNING_UNSCALED /************************************************************************** * * @function: * FT_Get_Kerning * * @description: * Return the kerning vector between two glyphs of the same face. * * @input: * face :: * A handle to a source face object. * * left_glyph :: * The index of the left glyph in the kern pair. * * right_glyph :: * The index of the right glyph in the kern pair. * * kern_mode :: * See @FT_Kerning_Mode for more information. * Determines the scale and dimension of the returned * kerning vector. * * @output: * akerning :: * The kerning vector. This is either in font units, * fractional pixels (26.6 format), or pixels for * scalable formats, and in pixels for fixed-sizes * formats. * * @return: * FreeType error code. 0~means success. * * @note: * Only horizontal layouts (left-to-right & right-to-left) are * supported by this method. Other layouts, or more sophisticated * kernings, are out of the scope of this API function -- they can be * implemented through format-specific interfaces. * * Kerning for OpenType fonts implemented in a `GPOS' table is not * supported; use @FT_HAS_KERNING to find out whether a font has data * that can be extracted with `FT_Get_Kerning'. */ FT_EXPORT( FT_Error ) FT_Get_Kerning( FT_Face face, FT_UInt left_glyph, FT_UInt right_glyph, FT_UInt kern_mode, FT_Vector *akerning ); /************************************************************************** * * @function: * FT_Get_Track_Kerning * * @description: * Return the track kerning for a given face object at a given size. * * @input: * face :: * A handle to a source face object. * * point_size :: * The point size in 16.16 fractional points. * * degree :: * The degree of tightness. Increasingly negative * values represent tighter track kerning, while * increasingly positive values represent looser track * kerning. Value zero means no track kerning. * * @output: * akerning :: * The kerning in 16.16 fractional points, to be * uniformly applied between all glyphs. * * @return: * FreeType error code. 0~means success. * * @note: * Currently, only the Type~1 font driver supports track kerning, * using data from AFM files (if attached with @FT_Attach_File or * @FT_Attach_Stream). * * Only very few AFM files come with track kerning data; please refer * to Adobe's AFM specification for more details. */ FT_EXPORT( FT_Error ) FT_Get_Track_Kerning( FT_Face face, FT_Fixed point_size, FT_Int degree, FT_Fixed* akerning ); /************************************************************************** * * @function: * FT_Get_Glyph_Name * * @description: * Retrieve the ASCII name of a given glyph in a face. This only * works for those faces where @FT_HAS_GLYPH_NAMES(face) returns~1. * * @input: * face :: * A handle to a source face object. * * glyph_index :: * The glyph index. * * buffer_max :: * The maximum number of bytes available in the * buffer. * * @output: * buffer :: * A pointer to a target buffer where the name is * copied to. * * @return: * FreeType error code. 0~means success. * * @note: * An error is returned if the face doesn't provide glyph names or if * the glyph index is invalid. In all cases of failure, the first * byte of `buffer' is set to~0 to indicate an empty name. * * The glyph name is truncated to fit within the buffer if it is too * long. The returned string is always zero-terminated. * * Be aware that FreeType reorders glyph indices internally so that * glyph index~0 always corresponds to the `missing glyph' (called * `.notdef'). * * This function always returns an error if the config macro * `FT_CONFIG_OPTION_NO_GLYPH_NAMES' is not defined in `ftoption.h'. */ FT_EXPORT( FT_Error ) FT_Get_Glyph_Name( FT_Face face, FT_UInt glyph_index, FT_Pointer buffer, FT_UInt buffer_max ); /************************************************************************** * * @function: * FT_Get_Postscript_Name * * @description: * Retrieve the ASCII PostScript name of a given face, if available. * This only works with PostScript, TrueType, and OpenType fonts. * * @input: * face :: * A handle to the source face object. * * @return: * A pointer to the face's PostScript name. NULL if unavailable. * * @note: * The returned pointer is owned by the face and is destroyed with * it. * * For variation fonts, this string changes if you select a different * instance, and you have to call `FT_Get_PostScript_Name' again to * retrieve it. FreeType follows Adobe TechNote #5902, `Generating * PostScript Names for Fonts Using OpenType Font Variations'. * * https://download.macromedia.com/pub/developer/opentype/tech-notes/5902.AdobePSNameGeneration.html * * [Since 2.9] Special PostScript names for named instances are only * returned if the named instance is set with @FT_Set_Named_Instance * (and the font has corresponding entries in its `fvar' table). If * @FT_IS_VARIATION returns true, the algorithmically derived * PostScript name is provided, not looking up special entries for * named instances. */ FT_EXPORT( const char* ) FT_Get_Postscript_Name( FT_Face face ); /************************************************************************** * * @function: * FT_Select_Charmap * * @description: * Select a given charmap by its encoding tag (as listed in * `freetype.h'). * * @inout: * face :: * A handle to the source face object. * * @input: * encoding :: * A handle to the selected encoding. * * @return: * FreeType error code. 0~means success. * * @note: * This function returns an error if no charmap in the face * corresponds to the encoding queried here. * * Because many fonts contain more than a single cmap for Unicode * encoding, this function has some special code to select the one * that covers Unicode best (`best' in the sense that a UCS-4 cmap is * preferred to a UCS-2 cmap). It is thus preferable to * @FT_Set_Charmap in this case. */ FT_EXPORT( FT_Error ) FT_Select_Charmap( FT_Face face, FT_Encoding encoding ); /************************************************************************** * * @function: * FT_Set_Charmap * * @description: * Select a given charmap for character code to glyph index mapping. * * @inout: * face :: * A handle to the source face object. * * @input: * charmap :: * A handle to the selected charmap. * * @return: * FreeType error code. 0~means success. * * @note: * This function returns an error if the charmap is not part of * the face (i.e., if it is not listed in the `face->charmaps' * table). * * It also fails if an OpenType type~14 charmap is selected (which * doesn't map character codes to glyph indices at all). */ FT_EXPORT( FT_Error ) FT_Set_Charmap( FT_Face face, FT_CharMap charmap ); /************************************************************************* * * @function: * FT_Get_Charmap_Index * * @description: * Retrieve index of a given charmap. * * @input: * charmap :: * A handle to a charmap. * * @return: * The index into the array of character maps within the face to which * `charmap' belongs. If an error occurs, -1 is returned. * */ FT_EXPORT( FT_Int ) FT_Get_Charmap_Index( FT_CharMap charmap ); /************************************************************************** * * @function: * FT_Get_Char_Index * * @description: * Return the glyph index of a given character code. This function * uses the currently selected charmap to do the mapping. * * @input: * face :: * A handle to the source face object. * * charcode :: * The character code. * * @return: * The glyph index. 0~means `undefined character code'. * * @note: * If you use FreeType to manipulate the contents of font files * directly, be aware that the glyph index returned by this function * doesn't always correspond to the internal indices used within the * file. This is done to ensure that value~0 always corresponds to * the `missing glyph'. If the first glyph is not named `.notdef', * then for Type~1 and Type~42 fonts, `.notdef' will be moved into * the glyph ID~0 position, and whatever was there will be moved to * the position `.notdef' had. For Type~1 fonts, if there is no * `.notdef' glyph at all, then one will be created at index~0 and * whatever was there will be moved to the last index -- Type~42 * fonts are considered invalid under this condition. */ FT_EXPORT( FT_UInt ) FT_Get_Char_Index( FT_Face face, FT_ULong charcode ); /************************************************************************** * * @function: * FT_Get_First_Char * * @description: * Return the first character code in the current charmap of a given * face, together with its corresponding glyph index. * * @input: * face :: * A handle to the source face object. * * @output: * agindex :: * Glyph index of first character code. 0~if charmap is * empty. * * @return: * The charmap's first character code. * * @note: * You should use this function together with @FT_Get_Next_Char to * parse all character codes available in a given charmap. The code * should look like this: * * { * FT_ULong charcode; * FT_UInt gindex; * * * charcode = FT_Get_First_Char( face, &gindex ); * while ( gindex != 0 ) * { * ... do something with (charcode,gindex) pair ... * * charcode = FT_Get_Next_Char( face, charcode, &gindex ); * } * } * * Be aware that character codes can have values up to 0xFFFFFFFF; * this might happen for non-Unicode or malformed cmaps. However, * even with regular Unicode encoding, so-called `last resort fonts' * (using SFNT cmap format 13, see function @FT_Get_CMap_Format) * normally have entries for all Unicode characters up to 0x1FFFFF, * which can cause *a lot* of iterations. * * Note that `*agindex' is set to~0 if the charmap is empty. The * result itself can be~0 in two cases: if the charmap is empty or * if the value~0 is the first valid character code. */ FT_EXPORT( FT_ULong ) FT_Get_First_Char( FT_Face face, FT_UInt *agindex ); /************************************************************************** * * @function: * FT_Get_Next_Char * * @description: * Return the next character code in the current charmap of a given * face following the value `char_code', as well as the corresponding * glyph index. * * @input: * face :: * A handle to the source face object. * * char_code :: * The starting character code. * * @output: * agindex :: * Glyph index of next character code. 0~if charmap * is empty. * * @return: * The charmap's next character code. * * @note: * You should use this function with @FT_Get_First_Char to walk * over all character codes available in a given charmap. See the * note for that function for a simple code example. * * Note that `*agindex' is set to~0 when there are no more codes in * the charmap. */ FT_EXPORT( FT_ULong ) FT_Get_Next_Char( FT_Face face, FT_ULong char_code, FT_UInt *agindex ); /************************************************************************* * * @function: * FT_Face_Properties * * @description: * Set or override certain (library or module-wide) properties on a * face-by-face basis. Useful for finer-grained control and avoiding * locks on shared structures (threads can modify their own faces as * they see fit). * * Contrary to @FT_Property_Set, this function uses @FT_Parameter so * that you can pass multiple properties to the target face in one call. * Note that only a subset of the available properties can be * controlled. * * * @FT_PARAM_TAG_STEM_DARKENING (stem darkening, corresponding to the * property `no-stem-darkening' provided by the `autofit', `cff', * `type1', and `t1cid' modules; see @no-stem-darkening). * * * @FT_PARAM_TAG_LCD_FILTER_WEIGHTS (LCD filter weights, corresponding * to function @FT_Library_SetLcdFilterWeights). * * * @FT_PARAM_TAG_RANDOM_SEED (seed value for the CFF, Type~1, and CID * `random' operator, corresponding to the `random-seed' property * provided by the `cff', `type1', and `t1cid' modules; see * @random-seed). * * Pass NULL as `data' in @FT_Parameter for a given tag to reset the * option and use the library or module default again. * * @input: * face :: * A handle to the source face object. * * num_properties :: * The number of properties that follow. * * properties :: * A handle to an @FT_Parameter array with `num_properties' elements. * * @return: * FreeType error code. 0~means success. * * @example: * Here an example that sets three properties. You must define * FT_CONFIG_OPTION_SUBPIXEL_RENDERING to make the LCD filter examples * work. * * { * FT_Parameter property1; * FT_Bool darken_stems = 1; * * FT_Parameter property2; * FT_LcdFiveTapFilter custom_weight = * { 0x11, 0x44, 0x56, 0x44, 0x11 }; * * FT_Parameter property3; * FT_Int32 random_seed = 314159265; * * FT_Parameter properties[3] = { property1, * property2, * property3 }; * * * property1.tag = FT_PARAM_TAG_STEM_DARKENING; * property1.data = &darken_stems; * * property2.tag = FT_PARAM_TAG_LCD_FILTER_WEIGHTS; * property2.data = custom_weight; * * property3.tag = FT_PARAM_TAG_RANDOM_SEED; * property3.data = &random_seed; * * FT_Face_Properties( face, 3, properties ); * } * * The next example resets a single property to its default value. * * { * FT_Parameter property; * * * property.tag = FT_PARAM_TAG_LCD_FILTER_WEIGHTS; * property.data = NULL; * * FT_Face_Properties( face, 1, &property ); * } * * @since: * 2.8 * */ FT_EXPORT( FT_Error ) FT_Face_Properties( FT_Face face, FT_UInt num_properties, FT_Parameter* properties ); /************************************************************************** * * @function: * FT_Get_Name_Index * * @description: * Return the glyph index of a given glyph name. * * @input: * face :: * A handle to the source face object. * * glyph_name :: * The glyph name. * * @return: * The glyph index. 0~means `undefined character code'. */ FT_EXPORT( FT_UInt ) FT_Get_Name_Index( FT_Face face, FT_String* glyph_name ); /************************************************************************* * * @enum: * FT_SUBGLYPH_FLAG_XXX * * @description: * A list of constants describing subglyphs. Please refer to the * `glyf' table description in the OpenType specification for the * meaning of the various flags (which get synthesized for * non-OpenType subglyphs). * * https://docs.microsoft.com/en-us/typography/opentype/spec/glyf#composite-glyph-description * * @values: * FT_SUBGLYPH_FLAG_ARGS_ARE_WORDS :: * FT_SUBGLYPH_FLAG_ARGS_ARE_XY_VALUES :: * FT_SUBGLYPH_FLAG_ROUND_XY_TO_GRID :: * FT_SUBGLYPH_FLAG_SCALE :: * FT_SUBGLYPH_FLAG_XY_SCALE :: * FT_SUBGLYPH_FLAG_2X2 :: * FT_SUBGLYPH_FLAG_USE_MY_METRICS :: * */ #define FT_SUBGLYPH_FLAG_ARGS_ARE_WORDS 1 #define FT_SUBGLYPH_FLAG_ARGS_ARE_XY_VALUES 2 #define FT_SUBGLYPH_FLAG_ROUND_XY_TO_GRID 4 #define FT_SUBGLYPH_FLAG_SCALE 8 #define FT_SUBGLYPH_FLAG_XY_SCALE 0x40 #define FT_SUBGLYPH_FLAG_2X2 0x80 #define FT_SUBGLYPH_FLAG_USE_MY_METRICS 0x200 /************************************************************************* * * @function: * FT_Get_SubGlyph_Info * * @description: * Retrieve a description of a given subglyph. Only use it if * `glyph->format' is @FT_GLYPH_FORMAT_COMPOSITE; an error is * returned otherwise. * * @input: * glyph :: * The source glyph slot. * * sub_index :: * The index of the subglyph. Must be less than * `glyph->num_subglyphs'. * * @output: * p_index :: * The glyph index of the subglyph. * * p_flags :: * The subglyph flags, see @FT_SUBGLYPH_FLAG_XXX. * * p_arg1 :: * The subglyph's first argument (if any). * * p_arg2 :: * The subglyph's second argument (if any). * * p_transform :: * The subglyph transformation (if any). * * @return: * FreeType error code. 0~means success. * * @note: * The values of `*p_arg1', `*p_arg2', and `*p_transform' must be * interpreted depending on the flags returned in `*p_flags'. See the * OpenType specification for details. * */ FT_EXPORT( FT_Error ) FT_Get_SubGlyph_Info( FT_GlyphSlot glyph, FT_UInt sub_index, FT_Int *p_index, FT_UInt *p_flags, FT_Int *p_arg1, FT_Int *p_arg2, FT_Matrix *p_transform ); /************************************************************************** * * @section: * layer_management * * @title: * Glyph Layer Management * * @abstract: * Retrieving and manipulating OpenType's `COLR' table data. * * @description: * The functions described here allow access of colored glyph layer data * in OpenType's `COLR' tables. */ /********************************************************************** * * @struct: * FT_LayerIterator * * @description: * This iterator object is needed for @FT_Get_Color_Glyph_Layer. * * @fields: * num_layers :: * The number of glyph layers for the requested glyph index. Will be * set by @FT_Get_Color_Glyph_Layer. * * layer :: * The current layer. Will be set by @FT_Get_Color_Glyph_Layer. * * p :: * An opaque pointer into `COLR' table data. The caller must set this * to NULL before the first call of @FT_Get_Color_Glyph_Layer. */ typedef struct FT_LayerIterator_ { FT_UInt num_layers; FT_UInt layer; FT_Byte* p; } FT_LayerIterator; /************************************************************************* * * @function: * FT_Get_Color_Glyph_Layer * * @description: * This is an interface to the `COLR' table in OpenType fonts to * iteratively retrieve the colored glyph layers associated with the * current glyph slot. * * https://docs.microsoft.com/en-us/typography/opentype/spec/colr * * The glyph layer data for a given glyph index, if present, provides an * alternative, multi-colour glyph representation: Instead of rendering * the outline or bitmap with the given glyph index, glyphs with the * indices and colors returned by this function are rendered layer by * layer. * * The returned elements are ordered in the z~direction from bottom to * top; the `n'th element should be rendered with the associated palette * color and blended on top of the already rendered layers (elements 0, * 1, ..., n-1). * * @input: * face :: * A handle to the parent face object. * * base_glyph :: * The glyph index the colored glyph layers are associated with. * * @inout: * iterator :: * An @FT_LayerIterator object. For the first call you should set * `iterator->p' to NULL. For all following calls, simply use the * same object again. * * @output: * aglyph_index :: * The glyph index of the current layer. * * acolor_index :: * The color index into the font face's color palette of the current * layer. The value 0xFFFF is special; it doesn't reference a palette * entry but indicates that the text foreground color should be used * instead (to be set up by the application outside of FreeType). * * The color palette can be retrieved with @FT_Palette_Select. * * @return: * Value~1 if everything is OK. If there are no more layers (or if * there are no layers at all), value~0 gets returned. In case of an * error, value~0 is returned also. * * @note: * This function is necessary if you want to handle glyph layers by * yourself. In particular, functions that operate with @FT_GlyphRec * objects (like @FT_Get_Glyph or @FT_Glyph_To_Bitmap) don't have access * to this information. * * @FT_Render_Glyph, however, handles colored glyph layers * automatically if the @FT_LOAD_COLOR flag is passed to it. * * @example: * { * FT_Color* palette; * FT_LayerIterator iterator; * * FT_Bool have_layers; * FT_UInt layer_glyph_index; * FT_UInt layer_color_index; * * * error = FT_Palette_Select( face, palette_index, &palette ); * if ( error ) * palette = NULL; * * iterator.p = NULL; * have_layers = FT_Get_Color_Glyph_Layer( face, * glyph_index, * &layer_glyph_index, * &layer_color_index, * &iterator ); * * if ( palette && have_layers ) * { * do * { * FT_Color layer_color; * * * if ( layer_color_index == 0xFFFF ) * layer_color = text_foreground_color; * else * layer_color = palette[layer_color_index]; * * // Load and render glyph `layer_glyph_index', then * // blend resulting pixmap (using color `layer_color') * // with previously created pixmaps. * * } while ( FT_Get_Color_Glyph_Layer( face, * glyph_index, * &layer_glyph_index, * &layer_color_index, * &iterator ) ); * } * } */ FT_EXPORT( FT_Bool ) FT_Get_Color_Glyph_Layer( FT_Face face, FT_UInt base_glyph, FT_UInt *aglyph_index, FT_UInt *acolor_index, FT_LayerIterator* iterator ); /************************************************************************** * * @section: * base_interface * */ /************************************************************************** * * @enum: * FT_FSTYPE_XXX * * @description: * A list of bit flags used in the `fsType' field of the OS/2 table * in a TrueType or OpenType font and the `FSType' entry in a * PostScript font. These bit flags are returned by * @FT_Get_FSType_Flags; they inform client applications of embedding * and subsetting restrictions associated with a font. * * See * https://www.adobe.com/content/dam/Adobe/en/devnet/acrobat/pdfs/FontPolicies.pdf * for more details. * * @values: * FT_FSTYPE_INSTALLABLE_EMBEDDING :: * Fonts with no fsType bit set may be embedded and permanently * installed on the remote system by an application. * * FT_FSTYPE_RESTRICTED_LICENSE_EMBEDDING :: * Fonts that have only this bit set must not be modified, embedded * or exchanged in any manner without first obtaining permission of * the font software copyright owner. * * FT_FSTYPE_PREVIEW_AND_PRINT_EMBEDDING :: * The font may be embedded and temporarily loaded on the remote * system. Documents containing Preview & Print fonts must be * opened `read-only'; no edits can be applied to the document. * * FT_FSTYPE_EDITABLE_EMBEDDING :: * The font may be embedded but must only be installed temporarily * on other systems. In contrast to Preview & Print fonts, * documents containing editable fonts may be opened for reading, * editing is permitted, and changes may be saved. * * FT_FSTYPE_NO_SUBSETTING :: * The font may not be subsetted prior to embedding. * * FT_FSTYPE_BITMAP_EMBEDDING_ONLY :: * Only bitmaps contained in the font may be embedded; no outline * data may be embedded. If there are no bitmaps available in the * font, then the font is unembeddable. * * @note: * The flags are ORed together, thus more than a single value can be * returned. * * While the `fsType' flags can indicate that a font may be embedded, * a license with the font vendor may be separately required to use * the font in this way. */ #define FT_FSTYPE_INSTALLABLE_EMBEDDING 0x0000 #define FT_FSTYPE_RESTRICTED_LICENSE_EMBEDDING 0x0002 #define FT_FSTYPE_PREVIEW_AND_PRINT_EMBEDDING 0x0004 #define FT_FSTYPE_EDITABLE_EMBEDDING 0x0008 #define FT_FSTYPE_NO_SUBSETTING 0x0100 #define FT_FSTYPE_BITMAP_EMBEDDING_ONLY 0x0200 /************************************************************************** * * @function: * FT_Get_FSType_Flags * * @description: * Return the `fsType' flags for a font. * * @input: * face :: * A handle to the source face object. * * @return: * The `fsType' flags, see @FT_FSTYPE_XXX. * * @note: * Use this function rather than directly reading the `fs_type' field * in the @PS_FontInfoRec structure, which is only guaranteed to * return the correct results for Type~1 fonts. * * @since: * 2.3.8 */ FT_EXPORT( FT_UShort ) FT_Get_FSType_Flags( FT_Face face ); /************************************************************************** * * @section: * glyph_variants * * @title: * Unicode Variation Sequences * * @abstract: * The FreeType~2 interface to Unicode Variation Sequences (UVS), * using the SFNT cmap format~14. * * @description: * Many characters, especially for CJK scripts, have variant forms. * They are a sort of grey area somewhere between being totally * irrelevant and semantically distinct; for this reason, the Unicode * consortium decided to introduce Variation Sequences (VS), * consisting of a Unicode base character and a variation selector * instead of further extending the already huge number of * characters. * * Unicode maintains two different sets, namely `Standardized * Variation Sequences' and registered `Ideographic Variation * Sequences' (IVS), collected in the `Ideographic Variation * Database' (IVD). * * https://unicode.org/Public/UCD/latest/ucd/StandardizedVariants.txt * https://unicode.org/reports/tr37/ * https://unicode.org/ivd/ * * To date (January 2017), the character with the most ideographic * variations is U+9089, having 32 such IVS. * * Three Mongolian Variation Selectors have the values U+180B-U+180D; * 256 generic Variation Selectors are encoded in the ranges * U+FE00-U+FE0F and U+E0100-U+E01EF. IVS currently use Variation * Selectors from the range U+E0100-U+E01EF only. * * A VS consists of the base character value followed by a single * Variation Selector. For example, to get the first variation of * U+9089, you have to write the character sequence `U+9089 U+E0100'. * * Adobe and MS decided to support both standardized and ideographic * VS with a new cmap subtable (format~14). It is an odd subtable * because it is not a mapping of input code points to glyphs, but * contains lists of all variations supported by the font. * * A variation may be either `default' or `non-default' for a given * font. A default variation is the one you will get for that code * point if you look it up in the standard Unicode cmap. A * non-default variation is a different glyph. * */ /************************************************************************** * * @function: * FT_Face_GetCharVariantIndex * * @description: * Return the glyph index of a given character code as modified by * the variation selector. * * @input: * face :: * A handle to the source face object. * * charcode :: * The character code point in Unicode. * * variantSelector :: * The Unicode code point of the variation selector. * * @return: * The glyph index. 0~means either `undefined character code', or * `undefined selector code', or `no variation selector cmap * subtable', or `current CharMap is not Unicode'. * * @note: * If you use FreeType to manipulate the contents of font files * directly, be aware that the glyph index returned by this function * doesn't always correspond to the internal indices used within * the file. This is done to ensure that value~0 always corresponds * to the `missing glyph'. * * This function is only meaningful if * a) the font has a variation selector cmap sub table, * and * b) the current charmap has a Unicode encoding. * * @since: * 2.3.6 */ FT_EXPORT( FT_UInt ) FT_Face_GetCharVariantIndex( FT_Face face, FT_ULong charcode, FT_ULong variantSelector ); /************************************************************************** * * @function: * FT_Face_GetCharVariantIsDefault * * @description: * Check whether this variation of this Unicode character is the one * to be found in the `cmap'. * * @input: * face :: * A handle to the source face object. * * charcode :: * The character codepoint in Unicode. * * variantSelector :: * The Unicode codepoint of the variation selector. * * @return: * 1~if found in the standard (Unicode) cmap, 0~if found in the * variation selector cmap, or -1 if it is not a variation. * * @note: * This function is only meaningful if the font has a variation * selector cmap subtable. * * @since: * 2.3.6 */ FT_EXPORT( FT_Int ) FT_Face_GetCharVariantIsDefault( FT_Face face, FT_ULong charcode, FT_ULong variantSelector ); /************************************************************************** * * @function: * FT_Face_GetVariantSelectors * * @description: * Return a zero-terminated list of Unicode variation selectors found * in the font. * * @input: * face :: * A handle to the source face object. * * @return: * A pointer to an array of selector code points, or NULL if there is * no valid variation selector cmap subtable. * * @note: * The last item in the array is~0; the array is owned by the * @FT_Face object but can be overwritten or released on the next * call to a FreeType function. * * @since: * 2.3.6 */ FT_EXPORT( FT_UInt32* ) FT_Face_GetVariantSelectors( FT_Face face ); /************************************************************************** * * @function: * FT_Face_GetVariantsOfChar * * @description: * Return a zero-terminated list of Unicode variation selectors found * for the specified character code. * * @input: * face :: * A handle to the source face object. * * charcode :: * The character codepoint in Unicode. * * @return: * A pointer to an array of variation selector code points that are * active for the given character, or NULL if the corresponding list * is empty. * * @note: * The last item in the array is~0; the array is owned by the * @FT_Face object but can be overwritten or released on the next * call to a FreeType function. * * @since: * 2.3.6 */ FT_EXPORT( FT_UInt32* ) FT_Face_GetVariantsOfChar( FT_Face face, FT_ULong charcode ); /************************************************************************** * * @function: * FT_Face_GetCharsOfVariant * * @description: * Return a zero-terminated list of Unicode character codes found for * the specified variation selector. * * @input: * face :: * A handle to the source face object. * * variantSelector :: * The variation selector code point in Unicode. * * @return: * A list of all the code points that are specified by this selector * (both default and non-default codes are returned) or NULL if there * is no valid cmap or the variation selector is invalid. * * @note: * The last item in the array is~0; the array is owned by the * @FT_Face object but can be overwritten or released on the next * call to a FreeType function. * * @since: * 2.3.6 */ FT_EXPORT( FT_UInt32* ) FT_Face_GetCharsOfVariant( FT_Face face, FT_ULong variantSelector ); /************************************************************************** * * @section: * computations * * @title: * Computations * * @abstract: * Crunching fixed numbers and vectors. * * @description: * This section contains various functions used to perform * computations on 16.16 fixed-float numbers or 2d vectors. * * @order: * FT_MulDiv * FT_MulFix * FT_DivFix * FT_RoundFix * FT_CeilFix * FT_FloorFix * FT_Vector_Transform * FT_Matrix_Multiply * FT_Matrix_Invert * */ /************************************************************************** * * @function: * FT_MulDiv * * @description: * Compute `(a*b)/c' with maximum accuracy, using a 64-bit * intermediate integer whenever necessary. * * This function isn't necessarily as fast as some processor-specific * operations, but is at least completely portable. * * @input: * a :: * The first multiplier. * * b :: * The second multiplier. * * c :: * The divisor. * * @return: * The result of `(a*b)/c'. This function never traps when trying to * divide by zero; it simply returns `MaxInt' or `MinInt' depending * on the signs of `a' and `b'. */ FT_EXPORT( FT_Long ) FT_MulDiv( FT_Long a, FT_Long b, FT_Long c ); /************************************************************************** * * @function: * FT_MulFix * * @description: * Compute `(a*b)/0x10000' with maximum accuracy. Its main use is to * multiply a given value by a 16.16 fixed-point factor. * * @input: * a :: * The first multiplier. * * b :: * The second multiplier. Use a 16.16 factor here whenever * possible (see note below). * * @return: * The result of `(a*b)/0x10000'. * * @note: * This function has been optimized for the case where the absolute * value of `a' is less than 2048, and `b' is a 16.16 scaling factor. * As this happens mainly when scaling from notional units to * fractional pixels in FreeType, it resulted in noticeable speed * improvements between versions 2.x and 1.x. * * As a conclusion, always try to place a 16.16 factor as the * _second_ argument of this function; this can make a great * difference. */ FT_EXPORT( FT_Long ) FT_MulFix( FT_Long a, FT_Long b ); /************************************************************************** * * @function: * FT_DivFix * * @description: * Compute `(a*0x10000)/b' with maximum accuracy. Its main use is to * divide a given value by a 16.16 fixed-point factor. * * @input: * a :: * The numerator. * * b :: * The denominator. Use a 16.16 factor here. * * @return: * The result of `(a*0x10000)/b'. */ FT_EXPORT( FT_Long ) FT_DivFix( FT_Long a, FT_Long b ); /************************************************************************** * * @function: * FT_RoundFix * * @description: * Round a 16.16 fixed number. * * @input: * a :: * The number to be rounded. * * @return: * `a' rounded to the nearest 16.16 fixed integer, halfway cases away * from zero. * * @note: * The function uses wrap-around arithmetic. */ FT_EXPORT( FT_Fixed ) FT_RoundFix( FT_Fixed a ); /************************************************************************** * * @function: * FT_CeilFix * * @description: * Compute the smallest following integer of a 16.16 fixed number. * * @input: * a :: * The number for which the ceiling function is to be computed. * * @return: * `a' rounded towards plus infinity. * * @note: * The function uses wrap-around arithmetic. */ FT_EXPORT( FT_Fixed ) FT_CeilFix( FT_Fixed a ); /************************************************************************** * * @function: * FT_FloorFix * * @description: * Compute the largest previous integer of a 16.16 fixed number. * * @input: * a :: * The number for which the floor function is to be computed. * * @return: * `a' rounded towards minus infinity. */ FT_EXPORT( FT_Fixed ) FT_FloorFix( FT_Fixed a ); /************************************************************************** * * @function: * FT_Vector_Transform * * @description: * Transform a single vector through a 2x2 matrix. * * @inout: * vector :: * The target vector to transform. * * @input: * matrix :: * A pointer to the source 2x2 matrix. * * @note: * The result is undefined if either `vector' or `matrix' is invalid. */ FT_EXPORT( void ) FT_Vector_Transform( FT_Vector* vec, const FT_Matrix* matrix ); /************************************************************************** * * @section: * version * * @title: * FreeType Version * * @abstract: * Functions and macros related to FreeType versions. * * @description: * Note that those functions and macros are of limited use because * even a new release of FreeType with only documentation changes * increases the version number. * * @order: * FT_Library_Version * * FREETYPE_MAJOR * FREETYPE_MINOR * FREETYPE_PATCH * * FT_Face_CheckTrueTypePatents * FT_Face_SetUnpatentedHinting * */ /************************************************************************* * * @enum: * FREETYPE_XXX * * @description: * These three macros identify the FreeType source code version. * Use @FT_Library_Version to access them at runtime. * * @values: * FREETYPE_MAJOR :: * The major version number. * FREETYPE_MINOR :: * The minor version number. * FREETYPE_PATCH :: * The patch level. * * @note: * The version number of FreeType if built as a dynamic link library * with the `libtool' package is _not_ controlled by these three * macros. * */ #define FREETYPE_MAJOR 2 #define FREETYPE_MINOR 9 #define FREETYPE_PATCH 1 /************************************************************************** * * @function: * FT_Library_Version * * @description: * Return the version of the FreeType library being used. This is * useful when dynamically linking to the library, since one cannot * use the macros @FREETYPE_MAJOR, @FREETYPE_MINOR, and * @FREETYPE_PATCH. * * @input: * library :: * A source library handle. * * @output: * amajor :: * The major version number. * * aminor :: * The minor version number. * * apatch :: * The patch version number. * * @note: * The reason why this function takes a `library' argument is because * certain programs implement library initialization in a custom way * that doesn't use @FT_Init_FreeType. * * In such cases, the library version might not be available before * the library object has been created. */ FT_EXPORT( void ) FT_Library_Version( FT_Library library, FT_Int *amajor, FT_Int *aminor, FT_Int *apatch ); /************************************************************************** * * @function: * FT_Face_CheckTrueTypePatents * * @description: * Deprecated, does nothing. * * @input: * face :: * A face handle. * * @return: * Always returns false. * * @note: * Since May 2010, TrueType hinting is no longer patented. * * @since: * 2.3.5 */ FT_EXPORT( FT_Bool ) FT_Face_CheckTrueTypePatents( FT_Face face ); /************************************************************************** * * @function: * FT_Face_SetUnpatentedHinting * * @description: * Deprecated, does nothing. * * @input: * face :: * A face handle. * * value :: * New boolean setting. * * @return: * Always returns false. * * @note: * Since May 2010, TrueType hinting is no longer patented. * * @since: * 2.3.5 */ FT_EXPORT( FT_Bool ) FT_Face_SetUnpatentedHinting( FT_Face face, FT_Bool value ); /* */ FT_END_HEADER #endif /* FREETYPE_H_ */ /* END */