1/*
2 * Copyright © 2017 Google, Inc.
3 *
4 * This is part of HarfBuzz, a text shaping library.
5 *
6 * Permission is hereby granted, without written agreement and without
7 * license or royalty fees, to use, copy, modify, and distribute this
8 * software and its documentation for any purpose, provided that the
9 * above copyright notice and the following two paragraphs appear in
10 * all copies of this software.
11 *
12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
16 * DAMAGE.
17 *
18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
21 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
22 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
23 *
24 * Google Author(s): Behdad Esfahbod
25 */
26
27#ifndef HB_OT_VAR_FVAR_TABLE_HH
28#define HB_OT_VAR_FVAR_TABLE_HH
29
30#include "hb-open-type.hh"
31
32/*
33 * fvar -- Font Variations
34 * https://docs.microsoft.com/en-us/typography/opentype/spec/fvar
35 */
36
37#define HB_OT_TAG_fvar HB_TAG('f','v','a','r')
38
39
40namespace OT {
41
42
43struct InstanceRecord
44{
45 friend struct fvar;
46
47 hb_array_t<const Fixed> get_coordinates (unsigned int axis_count) const
48 { return coordinatesZ.as_array (axis_count); }
49
50 bool sanitize (hb_sanitize_context_t *c, unsigned int axis_count) const
51 {
52 TRACE_SANITIZE (this);
53 return_trace (c->check_struct (this) &&
54 c->check_array (coordinatesZ.arrayZ, axis_count));
55 }
56
57 protected:
58 NameID subfamilyNameID;/* The name ID for entries in the 'name' table
59 * that provide subfamily names for this instance. */
60 HBUINT16 flags; /* Reserved for future use — set to 0. */
61 UnsizedArrayOf<Fixed>
62 coordinatesZ; /* The coordinates array for this instance. */
63 //NameID postScriptNameIDX;/*Optional. The name ID for entries in the 'name'
64 // * table that provide PostScript names for this
65 // * instance. */
66
67 public:
68 DEFINE_SIZE_UNBOUNDED (4);
69};
70
71struct AxisRecord
72{
73 enum
74 {
75 AXIS_FLAG_HIDDEN = 0x0001,
76 };
77
78 bool sanitize (hb_sanitize_context_t *c) const
79 {
80 TRACE_SANITIZE (this);
81 return_trace (c->check_struct (this));
82 }
83
84 public:
85 Tag axisTag; /* Tag identifying the design variation for the axis. */
86 Fixed minValue; /* The minimum coordinate value for the axis. */
87 Fixed defaultValue; /* The default coordinate value for the axis. */
88 Fixed maxValue; /* The maximum coordinate value for the axis. */
89 HBUINT16 flags; /* Axis flags. */
90 NameID axisNameID; /* The name ID for entries in the 'name' table that
91 * provide a display name for this axis. */
92
93 public:
94 DEFINE_SIZE_STATIC (20);
95};
96
97struct fvar
98{
99 static constexpr hb_tag_t tableTag = HB_OT_TAG_fvar;
100
101 bool has_data () const { return version.to_int (); }
102
103 bool sanitize (hb_sanitize_context_t *c) const
104 {
105 TRACE_SANITIZE (this);
106 return_trace (version.sanitize (c) &&
107 likely (version.major == 1) &&
108 c->check_struct (this) &&
109 axisSize == 20 && /* Assumed in our code. */
110 instanceSize >= axisCount * 4 + 4 &&
111 get_axes ().sanitize (c) &&
112 c->check_range (get_instance (0), instanceCount, instanceSize));
113 }
114
115 unsigned int get_axis_count () const { return axisCount; }
116
117 void get_axis_deprecated (unsigned int axis_index,
118 hb_ot_var_axis_t *info) const
119 {
120 const AxisRecord &axis = get_axes ()[axis_index];
121 info->tag = axis.axisTag;
122 info->name_id = axis.axisNameID;
123 info->default_value = axis.defaultValue / 65536.;
124 /* Ensure order, to simplify client math. */
125 info->min_value = MIN<float> (info->default_value, axis.minValue / 65536.);
126 info->max_value = MAX<float> (info->default_value, axis.maxValue / 65536.);
127 }
128
129 void get_axis_info (unsigned int axis_index,
130 hb_ot_var_axis_info_t *info) const
131 {
132 const AxisRecord &axis = get_axes ()[axis_index];
133 info->axis_index = axis_index;
134 info->tag = axis.axisTag;
135 info->name_id = axis.axisNameID;
136 info->flags = (hb_ot_var_axis_flags_t) (unsigned int) axis.flags;
137 info->default_value = axis.defaultValue / 65536.;
138 /* Ensure order, to simplify client math. */
139 info->min_value = MIN<float> (info->default_value, axis.minValue / 65536.);
140 info->max_value = MAX<float> (info->default_value, axis.maxValue / 65536.);
141 info->reserved = 0;
142 }
143
144 unsigned int get_axes_deprecated (unsigned int start_offset,
145 unsigned int *axes_count /* IN/OUT */,
146 hb_ot_var_axis_t *axes_array /* OUT */) const
147 {
148 if (axes_count)
149 {
150 /* TODO Rewrite as hb_array_t<>::sub-array() */
151 unsigned int count = axisCount;
152 start_offset = MIN (start_offset, count);
153
154 count -= start_offset;
155 axes_array += start_offset;
156
157 count = MIN (count, *axes_count);
158 *axes_count = count;
159
160 for (unsigned int i = 0; i < count; i++)
161 get_axis_deprecated (start_offset + i, axes_array + i);
162 }
163 return axisCount;
164 }
165
166 unsigned int get_axis_infos (unsigned int start_offset,
167 unsigned int *axes_count /* IN/OUT */,
168 hb_ot_var_axis_info_t *axes_array /* OUT */) const
169 {
170 if (axes_count)
171 {
172 /* TODO Rewrite as hb_array_t<>::sub-array() */
173 unsigned int count = axisCount;
174 start_offset = MIN (start_offset, count);
175
176 count -= start_offset;
177 axes_array += start_offset;
178
179 count = MIN (count, *axes_count);
180 *axes_count = count;
181
182 for (unsigned int i = 0; i < count; i++)
183 get_axis_info (start_offset + i, axes_array + i);
184 }
185 return axisCount;
186 }
187
188 bool find_axis_deprecated (hb_tag_t tag,
189 unsigned int *axis_index,
190 hb_ot_var_axis_t *info) const
191 {
192 const AxisRecord *axes = get_axes ();
193 unsigned int count = get_axis_count ();
194 for (unsigned int i = 0; i < count; i++)
195 if (axes[i].axisTag == tag)
196 {
197 if (axis_index)
198 *axis_index = i;
199 get_axis_deprecated (i, info);
200 return true;
201 }
202 if (axis_index)
203 *axis_index = HB_OT_VAR_NO_AXIS_INDEX;
204 return false;
205 }
206
207 bool find_axis_info (hb_tag_t tag,
208 hb_ot_var_axis_info_t *info) const
209 {
210 const AxisRecord *axes = get_axes ();
211 unsigned int count = get_axis_count ();
212 for (unsigned int i = 0; i < count; i++)
213 if (axes[i].axisTag == tag)
214 {
215 get_axis_info (i, info);
216 return true;
217 }
218 return false;
219 }
220
221 int normalize_axis_value (unsigned int axis_index, float v) const
222 {
223 hb_ot_var_axis_info_t axis;
224 get_axis_info (axis_index, &axis);
225
226 v = MAX (MIN (v, axis.max_value), axis.min_value); /* Clamp. */
227
228 if (v == axis.default_value)
229 return 0;
230 else if (v < axis.default_value)
231 v = (v - axis.default_value) / (axis.default_value - axis.min_value);
232 else
233 v = (v - axis.default_value) / (axis.max_value - axis.default_value);
234 return (int) (v * 16384.f + (v >= 0.f ? .5f : -.5f));
235 }
236
237 unsigned int get_instance_count () const { return instanceCount; }
238
239 hb_ot_name_id_t get_instance_subfamily_name_id (unsigned int instance_index) const
240 {
241 const InstanceRecord *instance = get_instance (instance_index);
242 if (unlikely (!instance)) return HB_OT_NAME_ID_INVALID;
243 return instance->subfamilyNameID;
244 }
245
246 hb_ot_name_id_t get_instance_postscript_name_id (unsigned int instance_index) const
247 {
248 const InstanceRecord *instance = get_instance (instance_index);
249 if (unlikely (!instance)) return HB_OT_NAME_ID_INVALID;
250 if (instanceSize >= axisCount * 4 + 6)
251 return StructAfter<NameID> (instance->get_coordinates (axisCount));
252 return HB_OT_NAME_ID_INVALID;
253 }
254
255 unsigned int get_instance_coords (unsigned int instance_index,
256 unsigned int *coords_length, /* IN/OUT */
257 float *coords /* OUT */) const
258 {
259 const InstanceRecord *instance = get_instance (instance_index);
260 if (unlikely (!instance))
261 {
262 if (coords_length)
263 *coords_length = 0;
264 return 0;
265 }
266
267 if (coords_length && *coords_length)
268 {
269 hb_array_t<const Fixed> instanceCoords = instance->get_coordinates (axisCount)
270 .sub_array (0, *coords_length);
271 for (unsigned int i = 0; i < instanceCoords.length; i++)
272 coords[i] = instanceCoords.arrayZ[i].to_float ();
273 }
274 return axisCount;
275 }
276
277 protected:
278 hb_array_t<const AxisRecord> get_axes () const
279 { return hb_array (&(this+firstAxis), axisCount); }
280
281 const InstanceRecord *get_instance (unsigned int i) const
282 {
283 if (unlikely (i >= instanceCount)) return nullptr;
284 return &StructAtOffset<InstanceRecord> (&StructAfter<InstanceRecord> (get_axes ()),
285 i * instanceSize);
286 }
287
288 protected:
289 FixedVersion<>version; /* Version of the fvar table
290 * initially set to 0x00010000u */
291 OffsetTo<AxisRecord>
292 firstAxis; /* Offset in bytes from the beginning of the table
293 * to the start of the AxisRecord array. */
294 HBUINT16 reserved; /* This field is permanently reserved. Set to 2. */
295 HBUINT16 axisCount; /* The number of variation axes in the font (the
296 * number of records in the axes array). */
297 HBUINT16 axisSize; /* The size in bytes of each VariationAxisRecord —
298 * set to 20 (0x0014) for this version. */
299 HBUINT16 instanceCount; /* The number of named instances defined in the font
300 * (the number of records in the instances array). */
301 HBUINT16 instanceSize; /* The size in bytes of each InstanceRecord — set
302 * to either axisCount * sizeof(Fixed) + 4, or to
303 * axisCount * sizeof(Fixed) + 6. */
304
305 public:
306 DEFINE_SIZE_STATIC (16);
307};
308
309} /* namespace OT */
310
311
312#endif /* HB_OT_VAR_FVAR_TABLE_HH */
313