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+/****************************************************************************
+ *
+ * aftypes.h
+ *
+ * Auto-fitter types (specification only).
+ *
+ * Copyright (C) 2003-2023 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 */
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