1
2 /*
3 * Copyright 2011 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10 #include "SkAdvancedTypefaceMetrics.h"
11 #include "SkTypes.h"
12
13 #if defined(SK_BUILD_FOR_WIN)
14 #include <dwrite.h>
15 #endif
16
17 #if defined(SK_BUILD_FOR_UNIX) || defined(SK_BUILD_FOR_ANDROID)
18 // forward declare structs needed for getAdvanceData() template for freetype
19 struct FT_FaceRec_;
20 typedef struct FT_FaceRec_* FT_Face;
21 #endif
22
23 #ifdef SK_BUILD_FOR_MAC
24 #import <ApplicationServices/ApplicationServices.h>
25 #endif
26
27 #ifdef SK_BUILD_FOR_IOS
28 #include <CoreText/CoreText.h>
29 #include <CoreGraphics/CoreGraphics.h>
30 #include <CoreFoundation/CoreFoundation.h>
31 #endif
32
33 namespace skia_advanced_typeface_metrics_utils {
34
35 const int16_t kInvalidAdvance = SK_MinS16;
36 const int16_t kDontCareAdvance = SK_MinS16 + 1;
37
38 template <typename Data>
stripUninterestingTrailingAdvancesFromRange(SkAdvancedTypefaceMetrics::AdvanceMetric<Data> * range)39 void stripUninterestingTrailingAdvancesFromRange(
40 SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* range) {
41 SkASSERT(false);
42 }
43
44 template <>
stripUninterestingTrailingAdvancesFromRange(SkAdvancedTypefaceMetrics::AdvanceMetric<int16_t> * range)45 void stripUninterestingTrailingAdvancesFromRange<int16_t>(
46 SkAdvancedTypefaceMetrics::AdvanceMetric<int16_t>* range) {
47 SkASSERT(range);
48
49 int expectedAdvanceCount = range->fEndId - range->fStartId + 1;
50 if (range->fAdvance.count() < expectedAdvanceCount) {
51 return;
52 }
53
54 for (int i = expectedAdvanceCount - 1; i >= 0; --i) {
55 if (range->fAdvance[i] != kDontCareAdvance &&
56 range->fAdvance[i] != kInvalidAdvance &&
57 range->fAdvance[i] != 0) {
58 range->fEndId = range->fStartId + i;
59 break;
60 }
61 }
62 }
63
64 template <typename Data>
resetRange(SkAdvancedTypefaceMetrics::AdvanceMetric<Data> * range,int startId)65 void resetRange(SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* range,
66 int startId) {
67 range->fStartId = startId;
68 range->fAdvance.setCount(0);
69 }
70
71 template <typename Data>
appendRange(SkAutoTDelete<SkAdvancedTypefaceMetrics::AdvanceMetric<Data>> * nextSlot,int startId)72 SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* appendRange(
73 SkAutoTDelete<SkAdvancedTypefaceMetrics::AdvanceMetric<Data> >* nextSlot,
74 int startId) {
75 nextSlot->reset(new SkAdvancedTypefaceMetrics::AdvanceMetric<Data>);
76 resetRange(nextSlot->get(), startId);
77 return nextSlot->get();
78 }
79
80 template <typename Data>
zeroWildcardsInRange(SkAdvancedTypefaceMetrics::AdvanceMetric<Data> * range)81 void zeroWildcardsInRange(
82 SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* range) {
83 SkASSERT(false);
84 }
85
86 template <>
zeroWildcardsInRange(SkAdvancedTypefaceMetrics::AdvanceMetric<int16_t> * range)87 void zeroWildcardsInRange<int16_t>(
88 SkAdvancedTypefaceMetrics::AdvanceMetric<int16_t>* range) {
89 SkASSERT(range);
90 if (range->fType != SkAdvancedTypefaceMetrics::WidthRange::kRange) {
91 return;
92 }
93 SkASSERT(range->fAdvance.count() == range->fEndId - range->fStartId + 1);
94
95 // Zero out wildcards.
96 for (int i = 0; i < range->fAdvance.count(); ++i) {
97 if (range->fAdvance[i] == kDontCareAdvance) {
98 range->fAdvance[i] = 0;
99 }
100 }
101 }
102
103 template <typename Data>
finishRange(SkAdvancedTypefaceMetrics::AdvanceMetric<Data> * range,int endId,typename SkAdvancedTypefaceMetrics::AdvanceMetric<Data>::MetricType type)104 void finishRange(
105 SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* range,
106 int endId,
107 typename SkAdvancedTypefaceMetrics::AdvanceMetric<Data>::MetricType
108 type) {
109 range->fEndId = endId;
110 range->fType = type;
111 stripUninterestingTrailingAdvancesFromRange(range);
112 int newLength;
113 if (type == SkAdvancedTypefaceMetrics::AdvanceMetric<Data>::kRange) {
114 newLength = range->fEndId - range->fStartId + 1;
115 } else {
116 if (range->fEndId == range->fStartId) {
117 range->fType =
118 SkAdvancedTypefaceMetrics::AdvanceMetric<Data>::kRange;
119 }
120 newLength = 1;
121 }
122 SkASSERT(range->fAdvance.count() >= newLength);
123 range->fAdvance.setCount(newLength);
124 zeroWildcardsInRange(range);
125 }
126
127 template <typename Data, typename FontHandle>
getAdvanceData(FontHandle fontHandle,int num_glyphs,const uint32_t * subsetGlyphIDs,uint32_t subsetGlyphIDsLength,bool (* getAdvance)(FontHandle fontHandle,int gId,Data * data))128 SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* getAdvanceData(
129 FontHandle fontHandle,
130 int num_glyphs,
131 const uint32_t* subsetGlyphIDs,
132 uint32_t subsetGlyphIDsLength,
133 bool (*getAdvance)(FontHandle fontHandle, int gId, Data* data)) {
134 // Assuming that on average, the ASCII representation of an advance plus
135 // a space is 8 characters and the ASCII representation of a glyph id is 3
136 // characters, then the following cut offs for using different range types
137 // apply:
138 // The cost of stopping and starting the range is 7 characers
139 // a. Removing 4 0's or don't care's is a win
140 // The cost of stopping and starting the range plus a run is 22
141 // characters
142 // b. Removing 3 repeating advances is a win
143 // c. Removing 2 repeating advances and 3 don't cares is a win
144 // When not currently in a range the cost of a run over a range is 16
145 // characaters, so:
146 // d. Removing a leading 0/don't cares is a win because it is omitted
147 // e. Removing 2 repeating advances is a win
148
149 SkAutoTDelete<SkAdvancedTypefaceMetrics::AdvanceMetric<Data> > result;
150 SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* curRange;
151 SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* prevRange = nullptr;
152 Data lastAdvance = kInvalidAdvance;
153 int repeatedAdvances = 0;
154 int wildCardsInRun = 0;
155 int trailingWildCards = 0;
156 uint32_t subsetIndex = 0;
157
158 // Limit the loop count to glyph id ranges provided.
159 int firstIndex = 0;
160 int lastIndex = num_glyphs;
161 if (subsetGlyphIDs) {
162 firstIndex = static_cast<int>(subsetGlyphIDs[0]);
163 lastIndex =
164 static_cast<int>(subsetGlyphIDs[subsetGlyphIDsLength - 1]) + 1;
165 }
166 curRange = appendRange(&result, firstIndex);
167
168 for (int gId = firstIndex; gId <= lastIndex; gId++) {
169 Data advance = kInvalidAdvance;
170 if (gId < lastIndex) {
171 // Get glyph id only when subset is nullptr, or the id is in subset.
172 SkASSERT(!subsetGlyphIDs || (subsetIndex < subsetGlyphIDsLength &&
173 static_cast<uint32_t>(gId) <= subsetGlyphIDs[subsetIndex]));
174 if (!subsetGlyphIDs ||
175 (subsetIndex < subsetGlyphIDsLength &&
176 static_cast<uint32_t>(gId) == subsetGlyphIDs[subsetIndex])) {
177 SkAssertResult(getAdvance(fontHandle, gId, &advance));
178 ++subsetIndex;
179 } else {
180 advance = kDontCareAdvance;
181 }
182 }
183 if (advance == lastAdvance) {
184 repeatedAdvances++;
185 trailingWildCards = 0;
186 } else if (advance == kDontCareAdvance) {
187 wildCardsInRun++;
188 trailingWildCards++;
189 } else if (curRange->fAdvance.count() ==
190 repeatedAdvances + 1 + wildCardsInRun) { // All in run.
191 if (lastAdvance == 0) {
192 resetRange(curRange, gId);
193 trailingWildCards = 0;
194 } else if (repeatedAdvances + 1 >= 2 || trailingWildCards >= 4) {
195 finishRange(curRange, gId - 1,
196 SkAdvancedTypefaceMetrics::WidthRange::kRun);
197 prevRange = curRange;
198 curRange = appendRange(&curRange->fNext, gId);
199 trailingWildCards = 0;
200 }
201 repeatedAdvances = 0;
202 wildCardsInRun = trailingWildCards;
203 trailingWildCards = 0;
204 } else {
205 if (lastAdvance == 0 &&
206 repeatedAdvances + 1 + wildCardsInRun >= 4) {
207 finishRange(curRange,
208 gId - repeatedAdvances - wildCardsInRun - 2,
209 SkAdvancedTypefaceMetrics::WidthRange::kRange);
210 prevRange = curRange;
211 curRange = appendRange(&curRange->fNext, gId);
212 trailingWildCards = 0;
213 } else if (trailingWildCards >= 4 && repeatedAdvances + 1 < 2) {
214 finishRange(curRange,
215 gId - trailingWildCards - 1,
216 SkAdvancedTypefaceMetrics::WidthRange::kRange);
217 prevRange = curRange;
218 curRange = appendRange(&curRange->fNext, gId);
219 trailingWildCards = 0;
220 } else if (lastAdvance != 0 &&
221 (repeatedAdvances + 1 >= 3 ||
222 (repeatedAdvances + 1 >= 2 && wildCardsInRun >= 3))) {
223 finishRange(curRange,
224 gId - repeatedAdvances - wildCardsInRun - 2,
225 SkAdvancedTypefaceMetrics::WidthRange::kRange);
226 curRange =
227 appendRange(&curRange->fNext,
228 gId - repeatedAdvances - wildCardsInRun - 1);
229 curRange->fAdvance.append(1, &lastAdvance);
230 finishRange(curRange, gId - 1,
231 SkAdvancedTypefaceMetrics::WidthRange::kRun);
232 prevRange = curRange;
233 curRange = appendRange(&curRange->fNext, gId);
234 trailingWildCards = 0;
235 }
236 repeatedAdvances = 0;
237 wildCardsInRun = trailingWildCards;
238 trailingWildCards = 0;
239 }
240 curRange->fAdvance.append(1, &advance);
241 if (advance != kDontCareAdvance) {
242 lastAdvance = advance;
243 }
244 }
245 if (curRange->fStartId == lastIndex) {
246 SkASSERT(prevRange);
247 SkASSERT(prevRange->fNext->fStartId == lastIndex);
248 prevRange->fNext.free();
249 } else {
250 finishRange(curRange, lastIndex - 1,
251 SkAdvancedTypefaceMetrics::WidthRange::kRange);
252 }
253 return result.detach();
254 }
255
256 // Make AdvanceMetric template functions available for linking with typename
257 // WidthRange and VerticalAdvanceRange.
258 #if defined(SK_BUILD_FOR_WIN)
259 template SkAdvancedTypefaceMetrics::WidthRange* getAdvanceData(
260 HDC hdc,
261 int num_glyphs,
262 const uint32_t* subsetGlyphIDs,
263 uint32_t subsetGlyphIDsLength,
264 bool (*getAdvance)(HDC hdc, int gId, int16_t* data));
265 template SkAdvancedTypefaceMetrics::WidthRange* getAdvanceData(
266 IDWriteFontFace* fontFace,
267 int num_glyphs,
268 const uint32_t* subsetGlyphIDs,
269 uint32_t subsetGlyphIDsLength,
270 bool (*getAdvance)(IDWriteFontFace* fontFace, int gId, int16_t* data));
271 #elif defined(SK_BUILD_FOR_UNIX) || defined(SK_BUILD_FOR_ANDROID)
272 template SkAdvancedTypefaceMetrics::WidthRange* getAdvanceData(
273 FT_Face face,
274 int num_glyphs,
275 const uint32_t* subsetGlyphIDs,
276 uint32_t subsetGlyphIDsLength,
277 bool (*getAdvance)(FT_Face face, int gId, int16_t* data));
278 #elif defined(SK_BUILD_FOR_MAC) || defined(SK_BUILD_FOR_IOS)
279 template SkAdvancedTypefaceMetrics::WidthRange* getAdvanceData(
280 CTFontRef ctFont,
281 int num_glyphs,
282 const uint32_t* subsetGlyphIDs,
283 uint32_t subsetGlyphIDsLength,
284 bool (*getAdvance)(CTFontRef ctFont, int gId, int16_t* data));
285 #endif
286 template void resetRange(
287 SkAdvancedTypefaceMetrics::WidthRange* range,
288 int startId);
289 template SkAdvancedTypefaceMetrics::WidthRange* appendRange(
290 SkAutoTDelete<SkAdvancedTypefaceMetrics::WidthRange >* nextSlot,
291 int startId);
292 template void finishRange<int16_t>(
293 SkAdvancedTypefaceMetrics::WidthRange* range,
294 int endId,
295 SkAdvancedTypefaceMetrics::WidthRange::MetricType type);
296
297 template void resetRange(
298 SkAdvancedTypefaceMetrics::VerticalAdvanceRange* range,
299 int startId);
300 template SkAdvancedTypefaceMetrics::VerticalAdvanceRange* appendRange(
301 SkAutoTDelete<SkAdvancedTypefaceMetrics::VerticalAdvanceRange >*
302 nextSlot,
303 int startId);
304 template void finishRange<SkAdvancedTypefaceMetrics::VerticalMetric>(
305 SkAdvancedTypefaceMetrics::VerticalAdvanceRange* range,
306 int endId,
307 SkAdvancedTypefaceMetrics::VerticalAdvanceRange::MetricType type);
308
309 // additional declaration needed for testing with a face of an unknown type
310 template SkAdvancedTypefaceMetrics::WidthRange* getAdvanceData(
311 void* fontData,
312 int num_glyphs,
313 const uint32_t* subsetGlyphIDs,
314 uint32_t subsetGlyphIDsLength,
315 bool (*getAdvance)(void* fontData, int gId, int16_t* data));
316
317 } // namespace skia_advanced_typeface_metrics_utils
318