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1 /****************************************************************************
2  *
3  * aflatin.h
4  *
5  *   Auto-fitter hinting routines for latin writing system
6  *   (specification).
7  *
8  * Copyright (C) 2003-2019 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