| /***************************************************************************/ |
| /* */ |
| /* ftautoh.h */ |
| /* */ |
| /* FreeType API for controlling the auto-hinter (specification only). */ |
| /* */ |
| /* Copyright 2012-2015 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 __FTAUTOH_H__ |
| #define __FTAUTOH_H__ |
| |
| #include <ft2build.h> |
| #include FT_FREETYPE_H |
| |
| #ifdef FREETYPE_H |
| #error "freetype.h of FreeType 1 has been loaded!" |
| #error "Please fix the directory search order for header files" |
| #error "so that freetype.h of FreeType 2 is found first." |
| #endif |
| |
| |
| FT_BEGIN_HEADER |
| |
| |
| /************************************************************************** |
| * |
| * @section: |
| * auto_hinter |
| * |
| * @title: |
| * The auto-hinter |
| * |
| * @abstract: |
| * Controlling the auto-hinting module. |
| * |
| * @description: |
| * While FreeType's auto-hinter doesn't expose API functions by itself, |
| * it is possible to control its behaviour with @FT_Property_Set and |
| * @FT_Property_Get. The following lists the available properties |
| * together with the necessary macros and structures. |
| * |
| * Note that the auto-hinter's module name is `autofitter' for |
| * historical reasons. |
| * |
| */ |
| |
| |
| /************************************************************************** |
| * |
| * @property: |
| * glyph-to-script-map |
| * |
| * @description: |
| * *Experimental* *only* |
| * |
| * The auto-hinter provides various script modules to hint glyphs. |
| * Examples of supported scripts are Latin or CJK. Before a glyph is |
| * auto-hinted, the Unicode character map of the font gets examined, and |
| * the script is then determined based on Unicode character ranges, see |
| * below. |
| * |
| * OpenType fonts, however, often provide much more glyphs than |
| * character codes (small caps, superscripts, ligatures, swashes, etc.), |
| * to be controlled by so-called `features'. Handling OpenType features |
| * can be quite complicated and thus needs a separate library on top of |
| * FreeType. |
| * |
| * The mapping between glyph indices and scripts (in the auto-hinter |
| * sense, see the @FT_AUTOHINTER_SCRIPT_XXX values) is stored as an |
| * array with `num_glyphs' elements, as found in the font's @FT_Face |
| * structure. The `glyph-to-script-map' property returns a pointer to |
| * this array, which can be modified as needed. Note that the |
| * modification should happen before the first glyph gets processed by |
| * the auto-hinter so that the global analysis of the font shapes |
| * actually uses the modified mapping. |
| * |
| * The following example code demonstrates how to access it (omitting |
| * the error handling). |
| * |
| * { |
| * FT_Library library; |
| * FT_Face face; |
| * FT_Prop_GlyphToScriptMap prop; |
| * |
| * |
| * FT_Init_FreeType( &library ); |
| * FT_New_Face( library, "foo.ttf", 0, &face ); |
| * |
| * prop.face = face; |
| * |
| * FT_Property_Get( library, "autofitter", |
| * "glyph-to-script-map", &prop ); |
| * |
| * // adjust `prop.map' as needed right here |
| * |
| * FT_Load_Glyph( face, ..., FT_LOAD_FORCE_AUTOHINT ); |
| * } |
| * |
| */ |
| |
| |
| /************************************************************************** |
| * |
| * @enum: |
| * FT_AUTOHINTER_SCRIPT_XXX |
| * |
| * @description: |
| * *Experimental* *only* |
| * |
| * A list of constants used for the @glyph-to-script-map property to |
| * specify the script submodule the auto-hinter should use for hinting a |
| * particular glyph. |
| * |
| * @values: |
| * FT_AUTOHINTER_SCRIPT_NONE :: |
| * Don't auto-hint this glyph. |
| * |
| * FT_AUTOHINTER_SCRIPT_LATIN :: |
| * Apply the latin auto-hinter. For the auto-hinter, `latin' is a |
| * very broad term, including Cyrillic and Greek also since characters |
| * from those scripts share the same design constraints. |
| * |
| * By default, characters from the following Unicode ranges are |
| * assigned to this submodule. |
| * |
| * { |
| * U+0020 - U+007F // Basic Latin (no control characters) |
| * U+00A0 - U+00FF // Latin-1 Supplement (no control characters) |
| * U+0100 - U+017F // Latin Extended-A |
| * U+0180 - U+024F // Latin Extended-B |
| * U+0250 - U+02AF // IPA Extensions |
| * U+02B0 - U+02FF // Spacing Modifier Letters |
| * U+0300 - U+036F // Combining Diacritical Marks |
| * U+0370 - U+03FF // Greek and Coptic |
| * U+0400 - U+04FF // Cyrillic |
| * U+0500 - U+052F // Cyrillic Supplement |
| * U+1D00 - U+1D7F // Phonetic Extensions |
| * U+1D80 - U+1DBF // Phonetic Extensions Supplement |
| * U+1DC0 - U+1DFF // Combining Diacritical Marks Supplement |
| * U+1E00 - U+1EFF // Latin Extended Additional |
| * U+1F00 - U+1FFF // Greek Extended |
| * U+2000 - U+206F // General Punctuation |
| * U+2070 - U+209F // Superscripts and Subscripts |
| * U+20A0 - U+20CF // Currency Symbols |
| * U+2150 - U+218F // Number Forms |
| * U+2460 - U+24FF // Enclosed Alphanumerics |
| * U+2C60 - U+2C7F // Latin Extended-C |
| * U+2DE0 - U+2DFF // Cyrillic Extended-A |
| * U+2E00 - U+2E7F // Supplemental Punctuation |
| * U+A640 - U+A69F // Cyrillic Extended-B |
| * U+A720 - U+A7FF // Latin Extended-D |
| * U+FB00 - U+FB06 // Alphab. Present. Forms (Latin Ligatures) |
| * U+1D400 - U+1D7FF // Mathematical Alphanumeric Symbols |
| * U+1F100 - U+1F1FF // Enclosed Alphanumeric Supplement |
| * } |
| * |
| * FT_AUTOHINTER_SCRIPT_CJK :: |
| * Apply the CJK auto-hinter, covering Chinese, Japanese, Korean, old |
| * Vietnamese, and some other scripts. |
| * |
| * By default, characters from the following Unicode ranges are |
| * assigned to this submodule. |
| * |
| * { |
| * U+1100 - U+11FF // Hangul Jamo |
| * U+2E80 - U+2EFF // CJK Radicals Supplement |
| * U+2F00 - U+2FDF // Kangxi Radicals |
| * U+2FF0 - U+2FFF // Ideographic Description Characters |
| * U+3000 - U+303F // CJK Symbols and Punctuation |
| * U+3040 - U+309F // Hiragana |
| * U+30A0 - U+30FF // Katakana |
| * U+3100 - U+312F // Bopomofo |
| * U+3130 - U+318F // Hangul Compatibility Jamo |
| * U+3190 - U+319F // Kanbun |
| * U+31A0 - U+31BF // Bopomofo Extended |
| * U+31C0 - U+31EF // CJK Strokes |
| * U+31F0 - U+31FF // Katakana Phonetic Extensions |
| * U+3200 - U+32FF // Enclosed CJK Letters and Months |
| * U+3300 - U+33FF // CJK Compatibility |
| * U+3400 - U+4DBF // CJK Unified Ideographs Extension A |
| * U+4DC0 - U+4DFF // Yijing Hexagram Symbols |
| * U+4E00 - U+9FFF // CJK Unified Ideographs |
| * U+A960 - U+A97F // Hangul Jamo Extended-A |
| * U+AC00 - U+D7AF // Hangul Syllables |
| * U+D7B0 - U+D7FF // Hangul Jamo Extended-B |
| * U+F900 - U+FAFF // CJK Compatibility Ideographs |
| * U+FE10 - U+FE1F // Vertical forms |
| * U+FE30 - U+FE4F // CJK Compatibility Forms |
| * U+FF00 - U+FFEF // Halfwidth and Fullwidth Forms |
| * U+1B000 - U+1B0FF // Kana Supplement |
| * U+1D300 - U+1D35F // Tai Xuan Hing Symbols |
| * U+1F200 - U+1F2FF // Enclosed Ideographic Supplement |
| * U+20000 - U+2A6DF // CJK Unified Ideographs Extension B |
| * U+2A700 - U+2B73F // CJK Unified Ideographs Extension C |
| * U+2B740 - U+2B81F // CJK Unified Ideographs Extension D |
| * U+2F800 - U+2FA1F // CJK Compatibility Ideographs Supplement |
| * } |
| * |
| * FT_AUTOHINTER_SCRIPT_INDIC :: |
| * Apply the indic auto-hinter, covering all major scripts from the |
| * Indian sub-continent and some other related scripts like Thai, Lao, |
| * or Tibetan. |
| * |
| * By default, characters from the following Unicode ranges are |
| * assigned to this submodule. |
| * |
| * { |
| * U+0900 - U+0DFF // Indic Range |
| * U+0F00 - U+0FFF // Tibetan |
| * U+1900 - U+194F // Limbu |
| * U+1B80 - U+1BBF // Sundanese |
| * U+1C80 - U+1CDF // Meetei Mayak |
| * U+A800 - U+A82F // Syloti Nagri |
| * U+11800 - U+118DF // Sharada |
| * } |
| * |
| * Note that currently Indic support is rudimentary only, missing blue |
| * zone support. |
| * |
| */ |
| #define FT_AUTOHINTER_SCRIPT_NONE 0 |
| #define FT_AUTOHINTER_SCRIPT_LATIN 1 |
| #define FT_AUTOHINTER_SCRIPT_CJK 2 |
| #define FT_AUTOHINTER_SCRIPT_INDIC 3 |
| |
| |
| /************************************************************************** |
| * |
| * @struct: |
| * FT_Prop_GlyphToScriptMap |
| * |
| * @description: |
| * *Experimental* *only* |
| * |
| * The data exchange structure for the @glyph-to-script-map property. |
| * |
| */ |
| typedef struct FT_Prop_GlyphToScriptMap_ |
| { |
| FT_Face face; |
| FT_Byte* map; |
| |
| } FT_Prop_GlyphToScriptMap; |
| |
| |
| /************************************************************************** |
| * |
| * @property: |
| * fallback-script |
| * |
| * @description: |
| * *Experimental* *only* |
| * |
| * If no auto-hinter script module can be assigned to a glyph, a |
| * fallback script gets assigned to it (see also the |
| * @glyph-to-script-map property). By default, this is |
| * @FT_AUTOHINTER_SCRIPT_CJK. Using the `fallback-script' property, |
| * this fallback value can be changed. |
| * |
| * { |
| * FT_Library library; |
| * FT_UInt fallback_script = FT_AUTOHINTER_SCRIPT_NONE; |
| * |
| * |
| * FT_Init_FreeType( &library ); |
| * |
| * FT_Property_Set( library, "autofitter", |
| * "fallback-script", &fallback_script ); |
| * } |
| * |
| * @note: |
| * This property can be used with @FT_Property_Get also. |
| * |
| * It's important to use the right timing for changing this value: The |
| * creation of the glyph-to-script map that eventually uses the |
| * fallback script value gets triggered either by setting or reading a |
| * face-specific property like @glyph-to-script-map, or by auto-hinting |
| * any glyph from that face. In particular, if you have already created |
| * an @FT_Face structure but not loaded any glyph (using the |
| * auto-hinter), a change of the fallback script will affect this face. |
| * |
| */ |
| |
| |
| /************************************************************************** |
| * |
| * @property: |
| * default-script |
| * |
| * @description: |
| * *Experimental* *only* |
| * |
| * If FreeType gets compiled with FT_CONFIG_OPTION_USE_HARFBUZZ to make |
| * the HarfBuzz library access OpenType features for getting better |
| * glyph coverages, this property sets the (auto-fitter) script to be |
| * used for the default (OpenType) script data of a font's GSUB table. |
| * Features for the default script are intended for all scripts not |
| * explicitly handled in GSUB; an example is a `dlig' feature, |
| * containing the combination of the characters `T', `E', and `L' to |
| * form a `TEL' ligature. |
| * |
| * By default, this is @FT_AUTOHINTER_SCRIPT_LATIN. Using the |
| * `default-script' property, this default value can be changed. |
| * |
| * { |
| * FT_Library library; |
| * FT_UInt default_script = FT_AUTOHINTER_SCRIPT_NONE; |
| * |
| * |
| * FT_Init_FreeType( &library ); |
| * |
| * FT_Property_Set( library, "autofitter", |
| * "default-script", &default_script ); |
| * } |
| * |
| * @note: |
| * This property can be used with @FT_Property_Get also. |
| * |
| * It's important to use the right timing for changing this value: The |
| * creation of the glyph-to-script map that eventually uses the |
| * default script value gets triggered either by setting or reading a |
| * face-specific property like @glyph-to-script-map, or by auto-hinting |
| * any glyph from that face. In particular, if you have already created |
| * an @FT_Face structure but not loaded any glyph (using the |
| * auto-hinter), a change of the default script will affect this face. |
| * |
| */ |
| |
| |
| /************************************************************************** |
| * |
| * @property: |
| * increase-x-height |
| * |
| * @description: |
| * For ppem values in the range 6~<= ppem <= `increase-x-height', round |
| * up the font's x~height much more often than normally. If the value |
| * is set to~0, which is the default, this feature is switched off. Use |
| * this property to improve the legibility of small font sizes if |
| * necessary. |
| * |
| * { |
| * FT_Library library; |
| * FT_Face face; |
| * FT_Prop_IncreaseXHeight prop; |
| * |
| * |
| * FT_Init_FreeType( &library ); |
| * FT_New_Face( library, "foo.ttf", 0, &face ); |
| * FT_Set_Char_Size( face, 10 * 64, 0, 72, 0 ); |
| * |
| * prop.face = face; |
| * prop.limit = 14; |
| * |
| * FT_Property_Set( library, "autofitter", |
| * "increase-x-height", &prop ); |
| * } |
| * |
| * @note: |
| * This property can be used with @FT_Property_Get also. |
| * |
| * Set this value right after calling @FT_Set_Char_Size, but before |
| * loading any glyph (using the auto-hinter). |
| * |
| */ |
| |
| |
| /************************************************************************** |
| * |
| * @struct: |
| * FT_Prop_IncreaseXHeight |
| * |
| * @description: |
| * The data exchange structure for the @increase-x-height property. |
| * |
| */ |
| typedef struct FT_Prop_IncreaseXHeight_ |
| { |
| FT_Face face; |
| FT_UInt limit; |
| |
| } FT_Prop_IncreaseXHeight; |
| |
| |
| /************************************************************************** |
| * |
| * @property: |
| * warping |
| * |
| * @description: |
| * *Experimental* *only* |
| * |
| * If FreeType gets compiled with option AF_CONFIG_OPTION_USE_WARPER to |
| * activate the warp hinting code in the auto-hinter, this property |
| * switches warping on and off. |
| * |
| * Warping only works in `light' auto-hinting mode. The idea of the |
| * code is to slightly scale and shift a glyph along the non-hinted |
| * dimension (which is usually the horizontal axis) so that as much of |
| * its segments are aligned (more or less) to the grid. To find out a |
| * glyph's optimal scaling and shifting value, various parameter |
| * combinations are tried and scored. |
| * |
| * By default, warping is off. The example below shows how to switch on |
| * warping (omitting the error handling). |
| * |
| * { |
| * FT_Library library; |
| * FT_Bool warping = 1; |
| * |
| * |
| * FT_Init_FreeType( &library ); |
| * |
| * FT_Property_Set( library, "autofitter", |
| * "warping", &warping ); |
| * } |
| * |
| * @note: |
| * This property can be used with @FT_Property_Get also. |
| * |
| * The warping code can also change advance widths. Have a look at the |
| * `lsb_delta' and `rsb_delta' fields in the @FT_GlyphSlotRec structure |
| * for details on improving inter-glyph distances while rendering. |
| * |
| * Since warping is a global property of the auto-hinter it is best to |
| * change its value before rendering any face. Otherwise, you should |
| * reload all faces that get auto-hinted in `light' hinting mode. |
| * |
| */ |
| |
| |
| /* */ |
| |
| |
| FT_END_HEADER |
| |
| #endif /* __FTAUTOH_H__ */ |
| |
| |
| /* END */ |
