/***************************************************************************/
/* */
/*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
#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_Librarylibrary;
* FT_Face face;
* FT_Prop_GlyphToScriptMapprop;
*
*
* 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_LATIN1
#define FT_AUTOHINTER_SCRIPT_CJK2
#define FT_AUTOHINTER_SCRIPT_INDIC3
/**************************************************************************
*
* @struct:
* FT_Prop_GlyphToScriptMap
*
* @description:
* *Experimental* *only*
*
* The data exchange structure for the @glyph-to-script-map property.
*
*/
typedef structFT_Prop_GlyphToScriptMap_
{
FT_Face face;
FT_UShort*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_Librarylibrary;
* 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_Librarylibrary;
* 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_Faceface; * FT_Prop_IncreaseXHeightprop; * * * 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 structFT_Prop_IncreaseXHeight_{FT_Faceface;FT_UIntlimit;} 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_Librarylibrary; * 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 */
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