Home | History | Annotate | Download | only in autofit
      1 /****************************************************************************
      2  *
      3  * aflatin.h
      4  *
      5  *   Auto-fitter hinting routines for latin writing system
      6  *   (specification).
      7  *
      8  * Copyright 2003-2018 by
      9  * David Turner, Robert Wilhelm, and Werner Lemberg.
     10  *
     11  * This file is part of the FreeType project, and may only be used,
     12  * modified, and distributed under the terms of the FreeType project
     13  * license, LICENSE.TXT.  By continuing to use, modify, or distribute
     14  * this file you indicate that you have read the license and
     15  * understand and accept it fully.
     16  *
     17  */
     18 
     19 
     20 #ifndef AFLATIN_H_
     21 #define AFLATIN_H_
     22 
     23 #include "afhints.h"
     24 
     25 
     26 FT_BEGIN_HEADER
     27 
     28   /* the `latin' writing system */
     29 
     30   AF_DECLARE_WRITING_SYSTEM_CLASS( af_latin_writing_system_class )
     31 
     32 
     33   /* constants are given with units_per_em == 2048 in mind */
     34 #define AF_LATIN_CONSTANT( metrics, c )                                      \
     35   ( ( (c) * (FT_Long)( (AF_LatinMetrics)(metrics) )->units_per_em ) / 2048 )
     36 
     37 
     38   /*************************************************************************/
     39   /*************************************************************************/
     40   /*****                                                               *****/
     41   /*****            L A T I N   G L O B A L   M E T R I C S            *****/
     42   /*****                                                               *****/
     43   /*************************************************************************/
     44   /*************************************************************************/
     45 
     46 
     47   /*
     48    * The following declarations could be embedded in the file `aflatin.c';
     49    * they have been made semi-public to allow alternate writing system
     50    * hinters to re-use some of them.
     51    */
     52 
     53 
     54 #define AF_LATIN_IS_TOP_BLUE( b ) \
     55           ( (b)->properties & AF_BLUE_PROPERTY_LATIN_TOP )
     56 #define AF_LATIN_IS_SUB_TOP_BLUE( b ) \
     57           ( (b)->properties & AF_BLUE_PROPERTY_LATIN_SUB_TOP )
     58 #define AF_LATIN_IS_NEUTRAL_BLUE( b ) \
     59           ( (b)->properties & AF_BLUE_PROPERTY_LATIN_NEUTRAL )
     60 #define AF_LATIN_IS_X_HEIGHT_BLUE( b ) \
     61           ( (b)->properties & AF_BLUE_PROPERTY_LATIN_X_HEIGHT )
     62 #define AF_LATIN_IS_LONG_BLUE( b ) \
     63           ( (b)->properties & AF_BLUE_PROPERTY_LATIN_LONG )
     64 
     65 #define AF_LATIN_MAX_WIDTHS  16
     66 
     67 
     68 #define AF_LATIN_BLUE_ACTIVE      ( 1U << 0 ) /* zone height is <= 3/4px   */
     69 #define AF_LATIN_BLUE_TOP         ( 1U << 1 ) /* we have a top blue zone   */
     70 #define AF_LATIN_BLUE_SUB_TOP     ( 1U << 2 ) /* we have a subscript top   */
     71                                               /* blue zone                 */
     72 #define AF_LATIN_BLUE_NEUTRAL     ( 1U << 3 ) /* we have neutral blue zone */
     73 #define AF_LATIN_BLUE_ADJUSTMENT  ( 1U << 4 ) /* used for scale adjustment */
     74                                               /* optimization              */
     75 
     76 
     77   typedef struct  AF_LatinBlueRec_
     78   {
     79     AF_WidthRec  ref;
     80     AF_WidthRec  shoot;
     81     FT_Pos       ascender;
     82     FT_Pos       descender;
     83     FT_UInt      flags;
     84 
     85   } AF_LatinBlueRec, *AF_LatinBlue;
     86 
     87 
     88   typedef struct  AF_LatinAxisRec_
     89   {
     90     FT_Fixed         scale;
     91     FT_Pos           delta;
     92 
     93     FT_UInt          width_count;                 /* number of used widths */
     94     AF_WidthRec      widths[AF_LATIN_MAX_WIDTHS]; /* widths array          */
     95     FT_Pos           edge_distance_threshold;   /* used for creating edges */
     96     FT_Pos           standard_width;         /* the default stem thickness */
     97     FT_Bool          extra_light;         /* is standard width very light? */
     98 
     99     /* ignored for horizontal metrics */
    100     FT_UInt          blue_count;
    101     AF_LatinBlueRec  blues[AF_BLUE_STRINGSET_MAX];
    102 
    103     FT_Fixed         org_scale;
    104     FT_Pos           org_delta;
    105 
    106   } AF_LatinAxisRec, *AF_LatinAxis;
    107 
    108 
    109   typedef struct  AF_LatinMetricsRec_
    110   {
    111     AF_StyleMetricsRec  root;
    112     FT_UInt             units_per_em;
    113     AF_LatinAxisRec     axis[AF_DIMENSION_MAX];
    114 
    115   } AF_LatinMetricsRec, *AF_LatinMetrics;
    116 
    117 
    118   FT_LOCAL( FT_Error )
    119   af_latin_metrics_init( AF_LatinMetrics  metrics,
    120                          FT_Face          face );
    121 
    122   FT_LOCAL( void )
    123   af_latin_metrics_scale( AF_LatinMetrics  metrics,
    124                           AF_Scaler        scaler );
    125 
    126   FT_LOCAL( void )
    127   af_latin_metrics_init_widths( AF_LatinMetrics  metrics,
    128                                 FT_Face          face );
    129 
    130   FT_LOCAL( void )
    131   af_latin_metrics_check_digits( AF_LatinMetrics  metrics,
    132                                  FT_Face          face );
    133 
    134 
    135   /*************************************************************************/
    136   /*************************************************************************/
    137   /*****                                                               *****/
    138   /*****           L A T I N   G L Y P H   A N A L Y S I S             *****/
    139   /*****                                                               *****/
    140   /*************************************************************************/
    141   /*************************************************************************/
    142 
    143 #define AF_LATIN_HINTS_HORZ_SNAP    ( 1U << 0 ) /* stem width snapping  */
    144 #define AF_LATIN_HINTS_VERT_SNAP    ( 1U << 1 ) /* stem height snapping */
    145 #define AF_LATIN_HINTS_STEM_ADJUST  ( 1U << 2 ) /* stem width/height    */
    146                                                 /* adjustment           */
    147 #define AF_LATIN_HINTS_MONO         ( 1U << 3 ) /* monochrome rendering */
    148 
    149 
    150 #define AF_LATIN_HINTS_DO_HORZ_SNAP( h )             \
    151   AF_HINTS_TEST_OTHER( h, AF_LATIN_HINTS_HORZ_SNAP )
    152 
    153 #define AF_LATIN_HINTS_DO_VERT_SNAP( h )             \
    154   AF_HINTS_TEST_OTHER( h, AF_LATIN_HINTS_VERT_SNAP )
    155 
    156 #define AF_LATIN_HINTS_DO_STEM_ADJUST( h )             \
    157   AF_HINTS_TEST_OTHER( h, AF_LATIN_HINTS_STEM_ADJUST )
    158 
    159 #define AF_LATIN_HINTS_DO_MONO( h )             \
    160   AF_HINTS_TEST_OTHER( h, AF_LATIN_HINTS_MONO )
    161 
    162 
    163   /*
    164    * The next functions shouldn't normally be exported.  However, other
    165    * writing systems might like to use these functions as-is.
    166    */
    167   FT_LOCAL( FT_Error )
    168   af_latin_hints_compute_segments( AF_GlyphHints  hints,
    169                                    AF_Dimension   dim );
    170 
    171   FT_LOCAL( void )
    172   af_latin_hints_link_segments( AF_GlyphHints  hints,
    173                                 FT_UInt        width_count,
    174                                 AF_WidthRec*   widths,
    175                                 AF_Dimension   dim );
    176 
    177   FT_LOCAL( FT_Error )
    178   af_latin_hints_compute_edges( AF_GlyphHints  hints,
    179                                 AF_Dimension   dim );
    180 
    181   FT_LOCAL( FT_Error )
    182   af_latin_hints_detect_features( AF_GlyphHints  hints,
    183                                   FT_UInt        width_count,
    184                                   AF_WidthRec*   widths,
    185                                   AF_Dimension   dim );
    186 
    187 /* */
    188 
    189 FT_END_HEADER
    190 
    191 #endif /* AFLATIN_H_ */
    192 
    193 
    194 /* END */
    195