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-private.hh"
31
32 namespace OT {
33
34
35 struct InstanceRecord
36 {
37 inline bool sanitize (hb_sanitize_context_t *c, unsigned int axis_count) const
38 {
39 TRACE_SANITIZE (this);
40 return_trace (c->check_struct (this) &&
41 c->check_array (coordinates, coordinates[0].static_size, axis_count));
42 }
43
44 protected:
45 USHORT subfamilyNameID;/* The name ID for entries in the 'name' table
46 * that provide subfamily names for this instance. */
47 USHORT reserved; /* Reserved for future use — set to 0. */
48 Fixed coordinates[VAR];/* The coordinates array for this instance. */
49 //USHORT postScriptNameIDX;/*Optional. The name ID for entries in the 'name'
50 // * table that provide PostScript names for this
51 // * instance. */
52
53 public:
54 DEFINE_SIZE_ARRAY (4, coordinates);
55 };
56
57 struct AxisRecord
58 {
59 inline bool sanitize (hb_sanitize_context_t *c) const
60 {
61 TRACE_SANITIZE (this);
62 return_trace (c->check_struct (this));
63 }
64
65 public:
66 Tag axisTag; /* Tag identifying the design variation for the axis. */
67 Fixed minValue; /* The minimum coordinate value for the axis. */
68 Fixed defaultValue; /* The default coordinate value for the axis. */
69 Fixed maxValue; /* The maximum coordinate value for the axis. */
70 USHORT reserved; /* Reserved for future use — set to 0. */
71 USHORT axisNameID; /* The name ID for entries in the 'name' table that
72 * provide a display name for this axis. */
73
74 public:
75 DEFINE_SIZE_STATIC (20);
76 };
77
78
79 /*
80 * fvar — Font Variations Table
81 */
82
83 #define HB_OT_TAG_fvar HB_TAG('f','v','a','r')
84
85 struct fvar
86 {
87 static const hb_tag_t tableTag = HB_OT_TAG_fvar;
88
89 inline bool sanitize (hb_sanitize_context_t *c) const
90 {
91 TRACE_SANITIZE (this);
92 return_trace (version.sanitize (c) &&
93 likely (version.major == 1) &&
94 c->check_struct (this) &&
95 instanceSize >= axisCount * 4 + 4 &&
96 axisSize <= 1024 && /* Arbitrary, just to simplify overflow checks. */
97 instanceSize <= 1024 && /* Arbitrary, just to simplify overflow checks. */
98 c->check_range (this, things) &&
99 c->check_range (&StructAtOffset<char> (this, things),
100 axisCount * axisSize + instanceCount * instanceSize));
101 }
102
103 inline unsigned int get_axis_count (void) const
104 { return axisCount; }
105
106 inline bool get_axis (unsigned int index, hb_ot_var_axis_t *info) const
107 {
108 if (unlikely (index >= axisCount))
109 return false;
110
111 if (info)
112 {
113 const AxisRecord &axis = get_axes ()[index];
114 info->tag = axis.axisTag;
115 info->name_id = axis.axisNameID;
116 info->default_value = axis.defaultValue / 65536.;
117 /* Ensure order, to simplify client math. */
118 info->min_value = MIN<float> (info->default_value, axis.minValue / 65536.);
119 info->max_value = MAX<float> (info->default_value, axis.maxValue / 65536.);
120 }
121
122 return true;
123 }
124
125 inline unsigned int get_axis_infos (unsigned int start_offset,
126 unsigned int *axes_count /* IN/OUT */,
127 hb_ot_var_axis_t *axes_array /* OUT */) const
128 {
129 if (axes_count)
130 {
131 unsigned int count = axisCount;
132 start_offset = MIN (start_offset, count);
133
134 count -= start_offset;
135 axes_array += start_offset;
136
137 count = MIN (count, *axes_count);
138 *axes_count = count;
139
140 for (unsigned int i = 0; i < count; i++)
141 get_axis (start_offset + i, axes_array + i);
142 }
143 return axisCount;
144 }
145
146 inline bool find_axis (hb_tag_t tag, unsigned int *index, hb_ot_var_axis_t *info) const
147 {
148 const AxisRecord *axes = get_axes ();
149 unsigned int count = get_axis_count ();
150 for (unsigned int i = 0; i < count; i++)
151 if (axes[i].axisTag == tag)
152 {
153 if (index)
154 *index = i;
155 return get_axis (i, info);
156 }
157 if (index)
158 *index = HB_OT_VAR_NO_AXIS_INDEX;
159 return false;
160 }
161
162 inline int normalize_axis_value (unsigned int axis_index, float v) const
163 {
164 hb_ot_var_axis_t axis;
165 if (!get_axis (axis_index, &axis))
166 return 0;
167
168 v = MAX (MIN (v, axis.max_value), axis.min_value); /* Clamp. */
169
170 if (v == axis.default_value)
171 return 0;
172 else if (v < axis.default_value)
173 v = (v - axis.default_value) / (axis.default_value - axis.min_value);
174 else
175 v = (v - axis.default_value) / (axis.max_value - axis.default_value);
176 return (int) (v * 16384. + (v >= 0. ? .5 : -.5));
177 }
178
179 protected:
180 inline const AxisRecord * get_axes (void) const
181 { return &StructAtOffset<AxisRecord> (this, things); }
182
183 inline const InstanceRecord * get_instances (void) const
184 { return &StructAtOffset<InstanceRecord> (get_axes () + axisCount, 0); }
185
186 protected:
187 FixedVersion<>version; /* Version of the fvar table
188 * initially set to 0x00010000u */
189 Offset<> things; /* Offset in bytes from the beginning of the table
190 * to the start of the AxisRecord array. */
191 USHORT reserved; /* This field is permanently reserved. Set to 2. */
192 USHORT axisCount; /* The number of variation axes in the font (the
193 * number of records in the axes array). */
194 USHORT axisSize; /* The size in bytes of each VariationAxisRecord —
195 * set to 20 (0x0014) for this version. */
196 USHORT instanceCount; /* The number of named instances defined in the font
197 * (the number of records in the instances array). */
198 USHORT instanceSize; /* The size in bytes of each InstanceRecord — set
199 * to either axisCount * sizeof(Fixed) + 4, or to
200 * axisCount * sizeof(Fixed) + 6. */
201
202 public:
203 DEFINE_SIZE_STATIC (16);
204 };
205
206 } /* namespace OT */
207
208
209 #endif /* HB_OT_VAR_FVAR_TABLE_HH */