Line data Source code
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 0 : inline bool sanitize (hb_sanitize_context_t *c) const
90 : {
91 0 : TRACE_SANITIZE (this);
92 0 : 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 0 : inline unsigned int get_axis_count (void) const
104 0 : { return axisCount; }
105 :
106 0 : inline bool get_axis (unsigned int index, hb_ot_var_axis_t *info) const
107 : {
108 0 : if (unlikely (index >= axisCount))
109 0 : return false;
110 :
111 0 : if (info)
112 : {
113 0 : const AxisRecord &axis = get_axes ()[index];
114 0 : info->tag = axis.axisTag;
115 0 : info->name_id = axis.axisNameID;
116 0 : info->default_value = axis.defaultValue / 65536.;
117 : /* Ensure order, to simplify client math. */
118 0 : info->min_value = MIN<float> (info->default_value, axis.minValue / 65536.);
119 0 : info->max_value = MAX<float> (info->default_value, axis.maxValue / 65536.);
120 : }
121 :
122 0 : return true;
123 : }
124 :
125 0 : 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 0 : if (axes_count)
130 : {
131 0 : unsigned int count = axisCount;
132 0 : start_offset = MIN (start_offset, count);
133 :
134 0 : count -= start_offset;
135 0 : axes_array += start_offset;
136 :
137 0 : count = MIN (count, *axes_count);
138 0 : *axes_count = count;
139 :
140 0 : for (unsigned int i = 0; i < count; i++)
141 0 : get_axis (start_offset + i, axes_array + i);
142 : }
143 0 : return axisCount;
144 : }
145 :
146 0 : inline bool find_axis (hb_tag_t tag, unsigned int *index, hb_ot_var_axis_t *info) const
147 : {
148 0 : const AxisRecord *axes = get_axes ();
149 0 : unsigned int count = get_axis_count ();
150 0 : for (unsigned int i = 0; i < count; i++)
151 0 : if (axes[i].axisTag == tag)
152 : {
153 0 : if (index)
154 0 : *index = i;
155 0 : return get_axis (i, info);
156 : }
157 0 : if (index)
158 0 : *index = HB_OT_VAR_NO_AXIS_INDEX;
159 0 : return false;
160 : }
161 :
162 0 : inline int normalize_axis_value (unsigned int axis_index, float v) const
163 : {
164 : hb_ot_var_axis_t axis;
165 0 : if (!get_axis (axis_index, &axis))
166 0 : return 0;
167 :
168 0 : v = MAX (MIN (v, axis.max_value), axis.min_value); /* Clamp. */
169 :
170 0 : if (v == axis.default_value)
171 0 : return 0;
172 0 : else if (v < axis.default_value)
173 0 : v = (v - axis.default_value) / (axis.default_value - axis.min_value);
174 : else
175 0 : v = (v - axis.default_value) / (axis.max_value - axis.default_value);
176 0 : return (int) (v * 16384. + (v >= 0. ? .5 : -.5));
177 : }
178 :
179 : protected:
180 0 : inline const AxisRecord * get_axes (void) const
181 0 : { 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 */
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