kc3-lang/freetype/src/autofit/aftypes.h

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• Hash : 5bcaf51b
  Author :
  Date : 2021-07-23T11:59:58
  

  [autofit] Split `afwrtsys.h`. The header file `afwrtsys.h` has two distinct functions: to include the required writing system headers and also to generate code for each writing system. At each current use site only one or the other is used, with various macro trickery selecting one or the other. Split this header into `afws-decl.h` for the required writing system declarations and `afws-iter.h` for iterating over the writing systems to generate code. The motivation for this change is that the Visual C++ compiler treats the standard include guard idiom like `#pragma once` 'if no non-comment code or preprocessor directive comes before or after the standard form of the idiom'. It appears to check this after macro expansion, so if `WRITING_SYSTEM` expands to empty the bottom of `afwrtsys.h` is empty and looks like the standard include guard idiom which is treated like `#pragma once`, so subsequent inclusion of `afwrtsys.h` is elided. Fixes #1075. * src/autofit/afglobal.c (af_writing_system_classes), src/autofit/aftypes.h (AF_WritingSystem), src/autofit/rules.mk (AUTOF_DRV_H): Updated. * src/autofit/afwrtsys.h: Split into... * src/autofit/afws-decl.h, src/autofit/afws-iter.h: New files.

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• src/autofit/aftypes.h

• /****************************************************************************
   *
   * aftypes.h
   *
   *   Auto-fitter types (specification only).
   *
   * Copyright (C) 2003-2021 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 1/64th 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 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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