ref: df14e6c0b9592cbb24d5381dfc6106b14f915e75
dir: /src/autofit/aftypes.h/
/***************************************************************************/ /* */ /* aftypes.h */ /* */ /* Auto-fitter types (specification only). */ /* */ /* Copyright 2003-2009, 2011-2014 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. */ /* */ /***************************************************************************/ /************************************************************************* * * The auto-fitter is a complete rewrite of the old auto-hinter. * Its main feature is the ability to differentiate between different * writing systems and scripts in order to apply specific rules. * * The code has also been compartmentized into several entities that * should make algorithmic experimentation easier than with the old * code. * *************************************************************************/ #ifndef __AFTYPES_H__ #define __AFTYPES_H__ #include <ft2build.h> #include FT_FREETYPE_H #include FT_OUTLINE_H #include FT_INTERNAL_OBJECTS_H #include FT_INTERNAL_DEBUG_H #include "afblue.h" FT_BEGIN_HEADER /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** D E B U G G I N G *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ #ifdef FT_DEBUG_AUTOFIT #include FT_CONFIG_STANDARD_LIBRARY_H extern int _af_debug_disable_horz_hints; extern int _af_debug_disable_vert_hints; extern int _af_debug_disable_blue_hints; extern void* _af_debug_hints; #endif /* FT_DEBUG_AUTOFIT */ /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** U T I L I T Y S T U F F *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ typedef struct AF_WidthRec_ { FT_Pos org; /* original position/width in font units */ FT_Pos cur; /* current/scaled position/width in device sub-pixels */ FT_Pos fit; /* current/fitted position/width in device sub-pixels */ } AF_WidthRec, *AF_Width; FT_LOCAL( void ) af_sort_pos( FT_UInt count, FT_Pos* table ); FT_LOCAL( void ) af_sort_and_quantize_widths( FT_UInt* count, AF_Width widths, FT_Pos threshold ); /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** A N G L E T Y P E S *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ /* * The auto-fitter doesn't need a very high angular accuracy; * this allows us to speed up some computations considerably with a * light Cordic algorithm (see afangles.c). */ typedef FT_Int AF_Angle; #define AF_ANGLE_PI 256 #define AF_ANGLE_2PI ( AF_ANGLE_PI * 2 ) #define AF_ANGLE_PI2 ( AF_ANGLE_PI / 2 ) #define AF_ANGLE_PI4 ( AF_ANGLE_PI / 4 ) #if 0 /* * compute the angle of a given 2-D vector */ FT_LOCAL( AF_Angle ) af_angle_atan( FT_Pos dx, FT_Pos dy ); /* * compute `angle2 - angle1'; the result is always within * the range [-AF_ANGLE_PI .. AF_ANGLE_PI - 1] */ FT_LOCAL( AF_Angle ) af_angle_diff( AF_Angle angle1, AF_Angle angle2 ); #endif /* 0 */ #define AF_ANGLE_DIFF( result, angle1, angle2 ) \ FT_BEGIN_STMNT \ AF_Angle _delta = (angle2) - (angle1); \ \ \ _delta %= AF_ANGLE_2PI; \ if ( _delta < 0 ) \ _delta += AF_ANGLE_2PI; \ \ if ( _delta > AF_ANGLE_PI ) \ _delta -= AF_ANGLE_2PI; \ \ result = _delta; \ FT_END_STMNT /* opaque handle to glyph-specific hints -- see `afhints.h' for more * details */ typedef struct AF_GlyphHintsRec_* AF_GlyphHints; /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** S C A L E R S *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ /* * A scaler models the target pixel device that will receive the * auto-hinted glyph image. */ typedef enum AF_ScalerFlags_ { AF_SCALER_FLAG_NO_HORIZONTAL = 1, /* disable horizontal hinting */ AF_SCALER_FLAG_NO_VERTICAL = 2, /* disable vertical hinting */ AF_SCALER_FLAG_NO_ADVANCE = 4 /* disable advance hinting */ } AF_ScalerFlags; typedef struct AF_ScalerRec_ { FT_Face face; /* source font face */ FT_Fixed x_scale; /* from font units to 1/64th device pixels */ FT_Fixed y_scale; /* from font units to 1/64th device pixels */ FT_Pos x_delta; /* in 1/64th device pixels */ FT_Pos y_delta; /* in 1/64th device pixels */ FT_Render_Mode render_mode; /* monochrome, anti-aliased, LCD, etc. */ FT_UInt32 flags; /* additional control flags, see above */ } AF_ScalerRec, *AF_Scaler; #define AF_SCALER_EQUAL_SCALES( a, b ) \ ( (a)->x_scale == (b)->x_scale && \ (a)->y_scale == (b)->y_scale && \ (a)->x_delta == (b)->x_delta && \ (a)->y_delta == (b)->y_delta ) typedef struct AF_StyleMetricsRec_* AF_StyleMetrics; /* This function parses an FT_Face to compute global metrics for * a specific style. */ typedef FT_Error (*AF_WritingSystem_InitMetricsFunc)( AF_StyleMetrics metrics, FT_Face face ); typedef void (*AF_WritingSystem_ScaleMetricsFunc)( AF_StyleMetrics metrics, AF_Scaler scaler ); typedef void (*AF_WritingSystem_DoneMetricsFunc)( AF_StyleMetrics metrics ); typedef FT_Error (*AF_WritingSystem_InitHintsFunc)( AF_GlyphHints hints, AF_StyleMetrics metrics ); typedef void (*AF_WritingSystem_ApplyHintsFunc)( AF_GlyphHints hints, FT_Outline* outline, AF_StyleMetrics metrics ); /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** W R I T I N G S Y S T E M S *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ /* * For the auto-hinter, a writing system consists of multiple scripts that * can be handled similarly *in a typographical way*; the relationship is * not based on history. For example, both the Greek and the unrelated * Armenian scripts share the same features like ascender, descender, * x-height, etc. Essentially, a writing system is covered by a * submodule of the auto-fitter; it contains * * - a specific global analyzer that computes global metrics specific to * the script (based on script-specific characters to identify ascender * height, x-height, etc.), * * - a specific glyph analyzer that computes segments and edges for each * glyph covered by the script, * * - a specific grid-fitting algorithm that distorts the scaled glyph * outline according to the results of the glyph analyzer. */ #define __AFWRTSYS_H__ /* don't load header files */ #undef WRITING_SYSTEM #define WRITING_SYSTEM( ws, WS ) \ AF_WRITING_SYSTEM_ ## WS, /* The list of known writing systems. */ typedef enum AF_WritingSystem_ { #include "afwrtsys.h" AF_WRITING_SYSTEM_MAX /* do not remove */ } AF_WritingSystem; #undef __AFWRTSYS_H__ typedef struct AF_WritingSystemClassRec_ { AF_WritingSystem writing_system; FT_Offset style_metrics_size; AF_WritingSystem_InitMetricsFunc style_metrics_init; AF_WritingSystem_ScaleMetricsFunc style_metrics_scale; AF_WritingSystem_DoneMetricsFunc style_metrics_done; AF_WritingSystem_InitHintsFunc style_hints_init; AF_WritingSystem_ApplyHintsFunc style_hints_apply; } AF_WritingSystemClassRec; typedef const AF_WritingSystemClassRec* AF_WritingSystemClass; /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** S C R I P T S *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ /* * Each script is associated with a set of Unicode ranges that gets used * to test whether the font face supports the script. * * We use four-letter script tags from the OpenType specification, * extended by `NONE', which indicates `no script'. */ #undef SCRIPT #define SCRIPT( s, S, d, h, sc1, sc2, sc3 ) \ AF_SCRIPT_ ## S, /* The list of known scripts. */ typedef enum AF_Script_ { #include "afscript.h" AF_SCRIPT_MAX /* do not remove */ } AF_Script; typedef struct AF_Script_UniRangeRec_ { FT_UInt32 first; FT_UInt32 last; } AF_Script_UniRangeRec; #define AF_UNIRANGE_REC( a, b ) { (FT_UInt32)(a), (FT_UInt32)(b) } typedef const AF_Script_UniRangeRec* AF_Script_UniRange; typedef struct AF_ScriptClassRec_ { AF_Script script; AF_Script_UniRange script_uni_ranges; /* last must be { 0, 0 } */ FT_UInt32 standard_char1; /* for default width and height */ FT_UInt32 standard_char2; /* ditto */ FT_UInt32 standard_char3; /* ditto */ } AF_ScriptClassRec; typedef const AF_ScriptClassRec* AF_ScriptClass; /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** C O V E R A G E S *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ /* * Usually, a font contains more glyphs than can be addressed by its * character map. * * In the PostScript font world, encoding vectors specific to a given * task are used to select such glyphs, and these glyphs can be often * recognized by having a suffix in its glyph names. For example, a * superscript glyph `A' might be called `A.sup'. Unfortunately, this * naming scheme is not standardized and thus unusable for us. * * In the OpenType world, a better solution was invented, namely * `features', which cleanly separate a character's input encoding from * the corresponding glyph's appearance, and which don't use glyph names * at all. For our purposes, and slightly generalized, an OpenType * feature is a name of a mapping that maps character codes to * non-standard glyph indices (features get used for other things also). * For example, the `sups' feature provides superscript glyphs, thus * mapping character codes like `A' or `B' to superscript glyph * representation forms. How this mapping happens is completely * uninteresting to us. * * For the auto-hinter, a `coverage' represents all glyphs of an OpenType * feature collected in a set (as listed below) that can be hinted * together. To continue the above example, superscript glyphs must not * be hinted together with normal glyphs because the blue zones * completely differ. * * Note that FreeType itself doesn't compute coverages; it only provides * the glyphs addressable by the default Unicode character map. Instead, * we use the HarfBuzz library (if available), which has many functions * exactly for this purpose. * * AF_COVERAGE_DEFAULT is special: It should cover everything that isn't * listed separately (including the glyphs addressable by the character * map). In case HarfBuzz isn't available, it exactly covers the glyphs * addressable by the character map. * */ #undef COVERAGE #define COVERAGE( name, NAME, description, \ tag1, tag2, tag3, tag4 ) \ AF_COVERAGE_ ## NAME, typedef enum AF_Coverage_ { #include "afcover.h" AF_COVERAGE_DEFAULT } AF_Coverage; /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** S T Y L E S *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ /* * The topmost structure for modelling the auto-hinter glyph input data * is a `style class', grouping everything together. */ #undef STYLE #define STYLE( s, S, d, ws, sc, ss, c ) \ AF_STYLE_ ## S, /* The list of known styles. */ typedef enum AF_Style_ { #include "afstyles.h" AF_STYLE_MAX /* do not remove */ } AF_Style; typedef struct AF_StyleClassRec_ { AF_Style style; AF_WritingSystem writing_system; AF_Script script; AF_Blue_Stringset blue_stringset; AF_Coverage coverage; } AF_StyleClassRec; typedef const AF_StyleClassRec* AF_StyleClass; /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** S T Y L E M E T R I C S *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ typedef struct AF_FaceGlobalsRec_* AF_FaceGlobals; /* This is the main structure that combines everything. Autofit modules */ /* specific to writing systems derive their structures from it, for */ /* example `AF_LatinMetrics'. */ typedef struct AF_StyleMetricsRec_ { AF_StyleClass style_class; AF_ScalerRec scaler; FT_Bool digits_have_same_width; AF_FaceGlobals globals; /* to access properties */ } AF_StyleMetricsRec; /* Declare and define vtables for classes */ #ifndef FT_CONFIG_OPTION_PIC #define AF_DECLARE_WRITING_SYSTEM_CLASS( writing_system_class ) \ FT_CALLBACK_TABLE const AF_WritingSystemClassRec \ writing_system_class; #define AF_DEFINE_WRITING_SYSTEM_CLASS( \ writing_system_class, \ system, \ m_size, \ m_init, \ m_scale, \ m_done, \ h_init, \ h_apply ) \ FT_CALLBACK_TABLE_DEF \ const AF_WritingSystemClassRec writing_system_class = \ { \ system, \ \ m_size, \ \ m_init, \ m_scale, \ m_done, \ \ h_init, \ h_apply \ }; #define AF_DECLARE_SCRIPT_CLASS( script_class ) \ FT_CALLBACK_TABLE const AF_ScriptClassRec \ script_class; #define AF_DEFINE_SCRIPT_CLASS( \ script_class, \ script, \ ranges, \ std_char1, \ std_char2, \ std_char3 ) \ FT_CALLBACK_TABLE_DEF \ const AF_ScriptClassRec script_class = \ { \ script, \ ranges, \ std_char1, \ std_char2, \ std_char3 \ }; #define AF_DECLARE_STYLE_CLASS( style_class ) \ FT_CALLBACK_TABLE const AF_StyleClassRec \ style_class; #define AF_DEFINE_STYLE_CLASS( \ style_class, \ style, \ writing_system, \ script, \ blue_stringset, \ coverage ) \ FT_CALLBACK_TABLE_DEF \ const AF_StyleClassRec style_class = \ { \ style, \ writing_system, \ script, \ blue_stringset, \ coverage \ }; #else /* FT_CONFIG_OPTION_PIC */ #define AF_DECLARE_WRITING_SYSTEM_CLASS( writing_system_class ) \ FT_LOCAL( void ) \ FT_Init_Class_ ## writing_system_class( AF_WritingSystemClassRec* ac ); #define AF_DEFINE_WRITING_SYSTEM_CLASS( \ writing_system_class, \ system, \ m_size, \ m_init, \ m_scale, \ m_done, \ h_init, \ h_apply ) \ FT_LOCAL_DEF( void ) \ FT_Init_Class_ ## writing_system_class( AF_WritingSystemClassRec* ac ) \ { \ ac->writing_system = system; \ \ ac->style_metrics_size = m_size; \ \ ac->style_metrics_init = m_init; \ ac->style_metrics_scale = m_scale; \ ac->style_metrics_done = m_done; \ \ ac->style_hints_init = h_init; \ ac->style_hints_apply = h_apply; \ } #define AF_DECLARE_SCRIPT_CLASS( script_class ) \ FT_LOCAL( void ) \ FT_Init_Class_ ## script_class( AF_ScriptClassRec* ac ); #define AF_DEFINE_SCRIPT_CLASS( \ script_class, \ script_, \ ranges, \ std_char1, \ std_char2, \ std_char3 ) \ FT_LOCAL_DEF( void ) \ FT_Init_Class_ ## script_class( AF_ScriptClassRec* ac ) \ { \ ac->script = script_; \ ac->script_uni_ranges = ranges; \ ac->standard_char1 = std_char1; \ ac->standard_char2 = std_char2; \ ac->standard_char3 = std_char3; \ } #define AF_DECLARE_STYLE_CLASS( style_class ) \ FT_LOCAL( void ) \ FT_Init_Class_ ## style_class( AF_StyleClassRec* ac ); #define AF_DEFINE_STYLE_CLASS( \ style_class, \ style_, \ writing_system_, \ script_, \ blue_stringset_, \ coverage_ ) \ FT_LOCAL_DEF( void ) \ FT_Init_Class_ ## style_class( AF_StyleClassRec* ac ) \ { \ ac->style = style_; \ ac->writing_system = writing_system_; \ ac->script = script_; \ ac->blue_stringset = blue_stringset_; \ ac->coverage = coverage_; \ } #endif /* FT_CONFIG_OPTION_PIC */ /* */ FT_END_HEADER #endif /* __AFTYPES_H__ */ /* END */