1 /****************************************************************************
2 *
3 * ttmtx.c
4 *
5 * Load the metrics tables common to TTF and OTF fonts (body).
6 *
7 * Copyright (C) 2006-2019 by
8 * David Turner, Robert Wilhelm, and Werner Lemberg.
9 *
10 * This file is part of the FreeType project, and may only be used,
11 * modified, and distributed under the terms of the FreeType project
12 * license, LICENSE.TXT. By continuing to use, modify, or distribute
13 * this file you indicate that you have read the license and
14 * understand and accept it fully.
15 *
16 */
17
18
19 #include <ft2build.h>
20 #include FT_INTERNAL_DEBUG_H
21 #include FT_INTERNAL_STREAM_H
22 #include FT_TRUETYPE_TAGS_H
23
24 #ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
25 #include FT_SERVICE_METRICS_VARIATIONS_H
26 #endif
27
28 #include "ttmtx.h"
29
30 #include "sferrors.h"
31
32
33 /* IMPORTANT: The TT_HoriHeader and TT_VertHeader structures should */
34 /* be identical except for the names of their fields, */
35 /* which are different. */
36 /* */
37 /* This ensures that `tt_face_load_hmtx' is able to read */
38 /* both the horizontal and vertical headers. */
39
40
41 /**************************************************************************
42 *
43 * The macro FT_COMPONENT is used in trace mode. It is an implicit
44 * parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
45 * messages during execution.
46 */
47 #undef FT_COMPONENT
48 #define FT_COMPONENT ttmtx
49
50
51 /**************************************************************************
52 *
53 * @Function:
54 * tt_face_load_hmtx
55 *
56 * @Description:
57 * Load the `hmtx' or `vmtx' table into a face object.
58 *
59 * @Input:
60 * face ::
61 * A handle to the target face object.
62 *
63 * stream ::
64 * The input stream.
65 *
66 * vertical ::
67 * A boolean flag. If set, load `vmtx'.
68 *
69 * @Return:
70 * FreeType error code. 0 means success.
71 */
72 FT_LOCAL_DEF( FT_Error )
73 tt_face_load_hmtx( TT_Face face,
74 FT_Stream stream,
75 FT_Bool vertical )
76 {
77 FT_Error error;
78 FT_ULong tag, table_size;
79 FT_ULong* ptable_offset;
80 FT_ULong* ptable_size;
81
82
83 if ( vertical )
84 {
85 tag = TTAG_vmtx;
86 ptable_offset = &face->vert_metrics_offset;
87 ptable_size = &face->vert_metrics_size;
88 }
89 else
90 {
91 tag = TTAG_hmtx;
92 ptable_offset = &face->horz_metrics_offset;
93 ptable_size = &face->horz_metrics_size;
94 }
95
96 error = face->goto_table( face, tag, stream, &table_size );
97 if ( error )
98 goto Fail;
99
100 *ptable_size = table_size;
101 *ptable_offset = FT_STREAM_POS();
102
103 Fail:
104 return error;
105 }
106
107
108 /**************************************************************************
109 *
110 * @Function:
111 * tt_face_load_hhea
112 *
113 * @Description:
114 * Load the `hhea' or 'vhea' table into a face object.
115 *
116 * @Input:
117 * face ::
118 * A handle to the target face object.
119 *
120 * stream ::
121 * The input stream.
122 *
123 * vertical ::
124 * A boolean flag. If set, load `vhea'.
125 *
126 * @Return:
127 * FreeType error code. 0 means success.
128 */
129 FT_LOCAL_DEF( FT_Error )
130 tt_face_load_hhea( TT_Face face,
131 FT_Stream stream,
132 FT_Bool vertical )
133 {
134 FT_Error error;
135 TT_HoriHeader* header;
136
137 static const FT_Frame_Field metrics_header_fields[] =
138 {
139 #undef FT_STRUCTURE
140 #define FT_STRUCTURE TT_HoriHeader
141
142 FT_FRAME_START( 36 ),
143 FT_FRAME_ULONG ( Version ),
144 FT_FRAME_SHORT ( Ascender ),
145 FT_FRAME_SHORT ( Descender ),
146 FT_FRAME_SHORT ( Line_Gap ),
147 FT_FRAME_USHORT( advance_Width_Max ),
148 FT_FRAME_SHORT ( min_Left_Side_Bearing ),
149 FT_FRAME_SHORT ( min_Right_Side_Bearing ),
150 FT_FRAME_SHORT ( xMax_Extent ),
151 FT_FRAME_SHORT ( caret_Slope_Rise ),
152 FT_FRAME_SHORT ( caret_Slope_Run ),
153 FT_FRAME_SHORT ( caret_Offset ),
154 FT_FRAME_SHORT ( Reserved[0] ),
155 FT_FRAME_SHORT ( Reserved[1] ),
156 FT_FRAME_SHORT ( Reserved[2] ),
157 FT_FRAME_SHORT ( Reserved[3] ),
158 FT_FRAME_SHORT ( metric_Data_Format ),
159 FT_FRAME_USHORT( number_Of_HMetrics ),
160 FT_FRAME_END
161 };
162
163
164 if ( vertical )
165 {
166 void *v = &face->vertical;
167
168
169 error = face->goto_table( face, TTAG_vhea, stream, 0 );
170 if ( error )
171 goto Fail;
172
173 header = (TT_HoriHeader*)v;
174 }
175 else
176 {
177 error = face->goto_table( face, TTAG_hhea, stream, 0 );
178 if ( error )
179 goto Fail;
180
181 header = &face->horizontal;
182 }
183
184 if ( FT_STREAM_READ_FIELDS( metrics_header_fields, header ) )
185 goto Fail;
186
187 FT_TRACE3(( "Ascender: %5d\n", header->Ascender ));
188 FT_TRACE3(( "Descender: %5d\n", header->Descender ));
189 FT_TRACE3(( "number_Of_Metrics: %5u\n", header->number_Of_HMetrics ));
190
191 header->long_metrics = NULL;
192 header->short_metrics = NULL;
193
194 Fail:
195 return error;
196 }
197
198
199 /**************************************************************************
200 *
201 * @Function:
202 * tt_face_get_metrics
203 *
204 * @Description:
205 * Return the horizontal or vertical metrics in font units for a
206 * given glyph. The values are the left side bearing (top side
207 * bearing for vertical metrics) and advance width (advance height
208 * for vertical metrics).
209 *
210 * @Input:
211 * face ::
212 * A pointer to the TrueType face structure.
213 *
214 * vertical ::
215 * If set to TRUE, get vertical metrics.
216 *
217 * gindex ::
218 * The glyph index.
219 *
220 * @Output:
221 * abearing ::
222 * The bearing, either left side or top side.
223 *
224 * aadvance ::
225 * The advance width or advance height, depending on
226 * the `vertical' flag.
227 */
228 FT_LOCAL_DEF( void )
229 tt_face_get_metrics( TT_Face face,
230 FT_Bool vertical,
231 FT_UInt gindex,
232 FT_Short *abearing,
233 FT_UShort *aadvance )
234 {
235 FT_Error error;
236 FT_Stream stream = face->root.stream;
237 TT_HoriHeader* header;
238 FT_ULong table_pos, table_size, table_end;
239 FT_UShort k;
240
241 #ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
242 FT_Service_MetricsVariations var =
243 (FT_Service_MetricsVariations)face->var;
244 #endif
245
246
247 if ( vertical )
248 {
249 void* v = &face->vertical;
250
251
252 header = (TT_HoriHeader*)v;
253 table_pos = face->vert_metrics_offset;
254 table_size = face->vert_metrics_size;
255 }
256 else
257 {
258 header = &face->horizontal;
259 table_pos = face->horz_metrics_offset;
260 table_size = face->horz_metrics_size;
261 }
262
263 table_end = table_pos + table_size;
264
265 k = header->number_Of_HMetrics;
266
267 if ( k > 0 )
268 {
269 if ( gindex < (FT_UInt)k )
270 {
271 table_pos += 4 * gindex;
272 if ( table_pos + 4 > table_end )
273 goto NoData;
274
275 if ( FT_STREAM_SEEK( table_pos ) ||
276 FT_READ_USHORT( *aadvance ) ||
277 FT_READ_SHORT( *abearing ) )
278 goto NoData;
279 }
280 else
281 {
282 table_pos += 4 * ( k - 1 );
283 if ( table_pos + 4 > table_end )
284 goto NoData;
285
286 if ( FT_STREAM_SEEK( table_pos ) ||
287 FT_READ_USHORT( *aadvance ) )
288 goto NoData;
289
290 table_pos += 4 + 2 * ( gindex - k );
291 if ( table_pos + 2 > table_end )
292 *abearing = 0;
293 else
294 {
295 if ( !FT_STREAM_SEEK( table_pos ) )
296 (void)FT_READ_SHORT( *abearing );
297 }
298 }
299 }
300 else
301 {
302 NoData:
303 *abearing = 0;
304 *aadvance = 0;
305 }
306
307 #ifdef TT_CONFIG_OPTION_GX_VAR_SUPPORT
308 if ( var )
309 {
310 FT_Face f = FT_FACE( face );
311 FT_Int a = (FT_Int)*aadvance;
312 FT_Int b = (FT_Int)*abearing;
313
314
315 if ( vertical )
316 {
317 if ( var->vadvance_adjust )
318 var->vadvance_adjust( f, gindex, &a );
319 if ( var->tsb_adjust )
320 var->tsb_adjust( f, gindex, &b );
321 }
322 else
323 {
324 if ( var->hadvance_adjust )
325 var->hadvance_adjust( f, gindex, &a );
326 if ( var->lsb_adjust )
327 var->lsb_adjust( f, gindex, &b );
328 }
329
330 *aadvance = (FT_UShort)a;
331 *abearing = (FT_Short)b;
332 }
333 #endif
334 }
335
336
337 /* END */