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 
40 namespace OT {
41 
42 
43 struct InstanceRecord
44 {
45   friend struct fvar;
46 
get_coordinatesOT::InstanceRecord47   hb_array_t<const HBFixed> get_coordinates (unsigned int axis_count) const
48   { return coordinatesZ.as_array (axis_count); }
49 
sanitizeOT::InstanceRecord50   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<HBFixed>
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 
71 struct AxisRecord
72 {
cmpOT::AxisRecord73   int cmp (hb_tag_t key) const { return axisTag.cmp (key); }
74 
75   enum
76   {
77     AXIS_FLAG_HIDDEN	= 0x0001,
78   };
79 
80 #ifndef HB_DISABLE_DEPRECATED
get_axis_deprecatedOT::AxisRecord81   void get_axis_deprecated (hb_ot_var_axis_t *info) const
82   {
83     info->tag = axisTag;
84     info->name_id = axisNameID;
85     get_coordinates (info->min_value, info->default_value, info->max_value);
86   }
87 #endif
88 
get_axis_infoOT::AxisRecord89   void get_axis_info (unsigned axis_index, hb_ot_var_axis_info_t *info) const
90   {
91     info->axis_index = axis_index;
92     info->tag = axisTag;
93     info->name_id = axisNameID;
94     info->flags = (hb_ot_var_axis_flags_t) (unsigned int) flags;
95     get_coordinates (info->min_value, info->default_value, info->max_value);
96     info->reserved = 0;
97   }
98 
normalize_axis_valueOT::AxisRecord99   int normalize_axis_value (float v) const
100   {
101     float min_value, default_value, max_value;
102     get_coordinates (min_value, default_value, max_value);
103 
104     v = hb_clamp (v, min_value, max_value);
105 
106     if (v == default_value)
107       return 0;
108     else if (v < default_value)
109       v = (v - default_value) / (default_value - min_value);
110     else
111       v = (v - default_value) / (max_value - default_value);
112     return roundf (v * 16384.f);
113   }
114 
unnormalize_axis_valueOT::AxisRecord115   float unnormalize_axis_value (int v) const
116   {
117     float min_value, default_value, max_value;
118     get_coordinates (min_value, default_value, max_value);
119 
120     if (v == 0)
121       return default_value;
122     else if (v < 0)
123       return v * (default_value - min_value) / 16384.f + default_value;
124     else
125       return v * (max_value - default_value) / 16384.f + default_value;
126   }
127 
get_name_idOT::AxisRecord128   hb_ot_name_id_t get_name_id () const { return axisNameID; }
129 
sanitizeOT::AxisRecord130   bool sanitize (hb_sanitize_context_t *c) const
131   {
132     TRACE_SANITIZE (this);
133     return_trace (c->check_struct (this));
134   }
135 
136   protected:
get_coordinatesOT::AxisRecord137   void get_coordinates (float &min, float &default_, float &max) const
138   {
139     default_ = defaultValue / 65536.f;
140     /* Ensure order, to simplify client math. */
141     min = hb_min (default_, minValue / 65536.f);
142     max = hb_max (default_, maxValue / 65536.f);
143   }
144 
145   protected:
146   Tag		axisTag;	/* Tag identifying the design variation for the axis. */
147   HBFixed	minValue;	/* The minimum coordinate value for the axis. */
148   HBFixed	defaultValue;	/* The default coordinate value for the axis. */
149   HBFixed	maxValue;	/* The maximum coordinate value for the axis. */
150   HBUINT16	flags;		/* Axis flags. */
151   NameID	axisNameID;	/* The name ID for entries in the 'name' table that
152 				 * provide a display name for this axis. */
153 
154   public:
155   DEFINE_SIZE_STATIC (20);
156 };
157 
158 struct fvar
159 {
160   static constexpr hb_tag_t tableTag = HB_OT_TAG_fvar;
161 
has_dataOT::fvar162   bool has_data () const { return version.to_int (); }
163 
sanitizeOT::fvar164   bool sanitize (hb_sanitize_context_t *c) const
165   {
166     TRACE_SANITIZE (this);
167     return_trace (version.sanitize (c) &&
168 		  likely (version.major == 1) &&
169 		  c->check_struct (this) &&
170 		  axisSize == 20 && /* Assumed in our code. */
171 		  instanceSize >= axisCount * 4 + 4 &&
172 		  get_axes ().sanitize (c) &&
173 		  c->check_range (get_instance (0), instanceCount, instanceSize));
174   }
175 
get_axis_countOT::fvar176   unsigned int get_axis_count () const { return axisCount; }
177 
178 #ifndef HB_DISABLE_DEPRECATED
get_axes_deprecatedOT::fvar179   unsigned int get_axes_deprecated (unsigned int      start_offset,
180 				    unsigned int     *axes_count /* IN/OUT */,
181 				    hb_ot_var_axis_t *axes_array /* OUT */) const
182   {
183     if (axes_count)
184     {
185       hb_array_t<const AxisRecord> arr = get_axes ().sub_array (start_offset, axes_count);
186       for (unsigned i = 0; i < arr.length; ++i)
187 	arr[i].get_axis_deprecated (&axes_array[i]);
188     }
189     return axisCount;
190   }
191 #endif
192 
get_axis_infosOT::fvar193   unsigned int get_axis_infos (unsigned int           start_offset,
194 			       unsigned int          *axes_count /* IN/OUT */,
195 			       hb_ot_var_axis_info_t *axes_array /* OUT */) const
196   {
197     if (axes_count)
198     {
199       hb_array_t<const AxisRecord> arr = get_axes ().sub_array (start_offset, axes_count);
200       for (unsigned i = 0; i < arr.length; ++i)
201 	arr[i].get_axis_info (start_offset + i, &axes_array[i]);
202     }
203     return axisCount;
204   }
205 
206 #ifndef HB_DISABLE_DEPRECATED
207   bool
find_axis_deprecatedOT::fvar208   find_axis_deprecated (hb_tag_t tag, unsigned *axis_index, hb_ot_var_axis_t *info) const
209   {
210     unsigned i;
211     if (!axis_index) axis_index = &i;
212     *axis_index = HB_OT_VAR_NO_AXIS_INDEX;
213     auto axes = get_axes ();
214     return axes.lfind (tag, axis_index) && (axes[*axis_index].get_axis_deprecated (info), true);
215   }
216 #endif
217 
218   bool
find_axis_infoOT::fvar219   find_axis_info (hb_tag_t tag, hb_ot_var_axis_info_t *info) const
220   {
221     unsigned i;
222     auto axes = get_axes ();
223     return axes.lfind (tag, &i) && (axes[i].get_axis_info (i, info), true);
224   }
225 
normalize_axis_valueOT::fvar226   int normalize_axis_value (unsigned int axis_index, float v) const
227   { return get_axes ()[axis_index].normalize_axis_value (v); }
228 
unnormalize_axis_valueOT::fvar229   float unnormalize_axis_value (unsigned int axis_index, int v) const
230   { return get_axes ()[axis_index].unnormalize_axis_value (v); }
231 
get_instance_countOT::fvar232   unsigned int get_instance_count () const { return instanceCount; }
233 
get_instance_subfamily_name_idOT::fvar234   hb_ot_name_id_t get_instance_subfamily_name_id (unsigned int instance_index) const
235   {
236     const InstanceRecord *instance = get_instance (instance_index);
237     if (unlikely (!instance)) return HB_OT_NAME_ID_INVALID;
238     return instance->subfamilyNameID;
239   }
240 
get_instance_postscript_name_idOT::fvar241   hb_ot_name_id_t get_instance_postscript_name_id (unsigned int instance_index) const
242   {
243     const InstanceRecord *instance = get_instance (instance_index);
244     if (unlikely (!instance)) return HB_OT_NAME_ID_INVALID;
245     if (instanceSize >= axisCount * 4 + 6)
246       return StructAfter<NameID> (instance->get_coordinates (axisCount));
247     return HB_OT_NAME_ID_INVALID;
248   }
249 
get_instance_coordsOT::fvar250   unsigned int get_instance_coords (unsigned int  instance_index,
251 				    unsigned int *coords_length, /* IN/OUT */
252 				    float        *coords         /* OUT */) const
253   {
254     const InstanceRecord *instance = get_instance (instance_index);
255     if (unlikely (!instance))
256     {
257       if (coords_length)
258 	*coords_length = 0;
259       return 0;
260     }
261 
262     if (coords_length && *coords_length)
263     {
264       hb_array_t<const HBFixed> instanceCoords = instance->get_coordinates (axisCount)
265 							 .sub_array (0, *coords_length);
266       for (unsigned int i = 0; i < instanceCoords.length; i++)
267 	coords[i] = instanceCoords.arrayZ[i].to_float ();
268     }
269     return axisCount;
270   }
271 
collect_name_idsOT::fvar272   void collect_name_ids (hb_set_t *nameids) const
273   {
274     if (!has_data ()) return;
275 
276     + get_axes ()
277     | hb_map (&AxisRecord::get_name_id)
278     | hb_sink (nameids)
279     ;
280 
281     + hb_range ((unsigned) instanceCount)
282     | hb_map ([this] (const unsigned _) { return get_instance_subfamily_name_id (_); })
283     | hb_sink (nameids)
284     ;
285 
286     + hb_range ((unsigned) instanceCount)
287     | hb_map ([this] (const unsigned _) { return get_instance_postscript_name_id (_); })
288     | hb_sink (nameids)
289     ;
290   }
291 
292   protected:
get_axesOT::fvar293   hb_array_t<const AxisRecord> get_axes () const
294   { return hb_array (&(this+firstAxis), axisCount); }
295 
get_instanceOT::fvar296   const InstanceRecord *get_instance (unsigned int i) const
297   {
298     if (unlikely (i >= instanceCount)) return nullptr;
299    return &StructAtOffset<InstanceRecord> (&StructAfter<InstanceRecord> (get_axes ()),
300 					   i * instanceSize);
301   }
302 
303   protected:
304   FixedVersion<>version;	/* Version of the fvar table
305 				 * initially set to 0x00010000u */
306   Offset16To<AxisRecord>
307 		firstAxis;	/* Offset in bytes from the beginning of the table
308 				 * to the start of the AxisRecord array. */
309   HBUINT16	reserved;	/* This field is permanently reserved. Set to 2. */
310   HBUINT16	axisCount;	/* The number of variation axes in the font (the
311 				 * number of records in the axes array). */
312   HBUINT16	axisSize;	/* The size in bytes of each VariationAxisRecord —
313 				 * set to 20 (0x0014) for this version. */
314   HBUINT16	instanceCount;	/* The number of named instances defined in the font
315 				 * (the number of records in the instances array). */
316   HBUINT16	instanceSize;	/* The size in bytes of each InstanceRecord — set
317 				 * to either axisCount * sizeof(HBFixed) + 4, or to
318 				 * axisCount * sizeof(HBFixed) + 6. */
319 
320   public:
321   DEFINE_SIZE_STATIC (16);
322 };
323 
324 } /* namespace OT */
325 
326 
327 #endif /* HB_OT_VAR_FVAR_TABLE_HH */
328