Edit
kc3-lang/freetype/src/autofit/aftypes.h
Alexei Podtelezhnikov
- src/autofit/aftypes.h
-
/**************************************************************************** * * aftypes.h * * Auto-fitter types (specification only). * * Copyright (C) 2003-2024 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 compartmentalized into several entities that * should make algorithmic experimentation easier than with the old * code. * *************************************************************************/ #ifndef AFTYPES_H_ #define AFTYPES_H_ #include <freetype/freetype.h> #include <freetype/ftoutln.h> #include <freetype/internal/ftobjs.h> #include <freetype/internal/ftdebug.h> #include "afblue.h" #ifdef FT_DEBUG_AUTOFIT #include FT_CONFIG_STANDARD_LIBRARY_H #endif FT_BEGIN_HEADER /*************************************************************************/ /*************************************************************************/ /***** *****/ /***** D E B U G G I N G *****/ /***** *****/ /*************************************************************************/ /*************************************************************************/ #ifdef FT_DEBUG_AUTOFIT 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 subpixels */ FT_Pos fit; /* current/fitted position/width in device subpixels */ } 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 ); /* * 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. */ #define AF_SCALER_FLAG_NO_HORIZONTAL 1U /* disable horizontal hinting */ #define AF_SCALER_FLAG_NO_VERTICAL 2U /* disable vertical hinting */ #define AF_SCALER_FLAG_NO_ADVANCE 4U /* disable advance hinting */ typedef struct AF_ScalerRec_ { FT_Face face; /* source font face */ FT_Fixed x_scale; /* from font units to 1/64 device pixels */ FT_Fixed y_scale; /* from font units to 1/64 device pixels */ FT_Pos x_delta; /* in 1/64 device pixels */ FT_Pos y_delta; /* in 1/64 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 void (*AF_WritingSystem_GetStdWidthsFunc)( AF_StyleMetrics metrics, FT_Pos* stdHW, FT_Pos* stdVW ); typedef FT_Error (*AF_WritingSystem_InitHintsFunc)( AF_GlyphHints hints, AF_StyleMetrics metrics ); typedef FT_Error (*AF_WritingSystem_ApplyHintsFunc)( FT_UInt glyph_index, 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. */ #undef WRITING_SYSTEM #define WRITING_SYSTEM( ws, WS ) \ AF_WRITING_SYSTEM_ ## WS, /* The list of known writing systems. */ typedef enum AF_WritingSystem_ { #include "afws-iter.h" AF_WRITING_SYSTEM_MAX /* do not remove */ } AF_WritingSystem; 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_GetStdWidthsFunc style_metrics_getstdw; 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 two sets of Unicode ranges to test * whether the font face supports the script, and which non-base * characters the script contains. * * 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, H, ss ) \ 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; /* last element in the ranges must be { 0, 0 } */ AF_Script_UniRange script_uni_ranges; AF_Script_UniRange script_uni_nonbase_ranges; FT_Bool top_to_bottom_hinting; const char* standard_charstring; /* for default width and height */ } 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; #define AF_HINTING_BOTTOM_TO_TOP 0 #define AF_HINTING_TOP_TO_BOTTOM 1 /* Declare and define vtables for classes */ #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, \ m_stdw, \ h_init, \ h_apply ) \ FT_CALLBACK_TABLE_DEF \ const AF_WritingSystemClassRec writing_system_class = \ { \ system, \ \ m_size, \ \ m_init, \ m_scale, \ m_done, \ m_stdw, \ \ 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, \ nonbase_ranges, \ top_to_bottom, \ std_charstring ) \ FT_CALLBACK_TABLE_DEF \ const AF_ScriptClassRec script_class = \ { \ script, \ ranges, \ nonbase_ranges, \ top_to_bottom, \ std_charstring, \ }; #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 \ }; /* */ FT_END_HEADER #endif /* AFTYPES_H_ */ /* END */