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1 /* libs/graphics/sgl/SkRegion_path.cpp | |
2 ** | |
3 ** Copyright 2006, The Android Open Source Project | |
4 ** | |
5 ** Licensed under the Apache License, Version 2.0 (the "License"); | |
6 ** you may not use this file except in compliance with the License. | |
7 ** You may obtain a copy of the License at | |
8 ** | |
9 ** http://www.apache.org/licenses/LICENSE-2.0 | |
10 ** | |
11 ** Unless required by applicable law or agreed to in writing, software | |
12 ** distributed under the License is distributed on an "AS IS" BASIS, | |
13 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
14 ** See the License for the specific language governing permissions and | |
15 ** limitations under the License. | |
16 */ | |
17 | |
18 #include "SkRegionPriv.h" | |
19 #include "SkBlitter.h" | |
20 #include "SkScan.h" | |
21 #include "SkTDArray.h" | |
22 #include "SkPath.h" | |
23 | |
24 class SkRgnBuilder : public SkBlitter { | |
25 public: | |
26 virtual ~SkRgnBuilder(); | |
27 | |
28 // returns true if it could allocate the working storage needed | |
29 bool init(int maxHeight, int maxTransitions); | |
30 | |
31 void done() { | |
32 if (fCurrScanline != NULL) { | |
33 fCurrScanline->fXCount = (SkRegion::RunType)((int)(fCurrXPtr - fCurr
Scanline->firstX())); | |
34 if (!this->collapsWithPrev()) { // flush the last line | |
35 fCurrScanline = fCurrScanline->nextScanline(); | |
36 } | |
37 } | |
38 } | |
39 | |
40 int computeRunCount() const; | |
41 void copyToRect(SkIRect*) const; | |
42 void copyToRgn(SkRegion::RunType runs[]) const; | |
43 | |
44 virtual void blitH(int x, int y, int width); | |
45 | |
46 #ifdef SK_DEBUG | |
47 void dump() const { | |
48 SkDebugf("SkRgnBuilder: Top = %d\n", fTop); | |
49 const Scanline* line = (Scanline*)fStorage; | |
50 while (line < fCurrScanline) { | |
51 SkDebugf("SkRgnBuilder::Scanline: LastY=%d, fXCount=%d", line->fLast
Y, line->fXCount); | |
52 for (int i = 0; i < line->fXCount; i++) { | |
53 SkDebugf(" %d", line->firstX()[i]); | |
54 } | |
55 SkDebugf("\n"); | |
56 | |
57 line = line->nextScanline(); | |
58 } | |
59 } | |
60 #endif | |
61 private: | |
62 struct Scanline { | |
63 SkRegion::RunType fLastY; | |
64 SkRegion::RunType fXCount; | |
65 | |
66 SkRegion::RunType* firstX() const { return (SkRegion::RunType*)(this + 1
); } | |
67 Scanline* nextScanline() const { | |
68 return (Scanline*)((SkRegion::RunType*)(this + 1) + fXCount); | |
69 } | |
70 }; | |
71 SkRegion::RunType* fStorage; | |
72 Scanline* fCurrScanline; | |
73 Scanline* fPrevScanline; | |
74 // points at next avialable x[] in fCurrScanline | |
75 SkRegion::RunType* fCurrXPtr; | |
76 SkRegion::RunType fTop; // first Y value | |
77 | |
78 int fStorageCount; | |
79 | |
80 bool collapsWithPrev() { | |
81 if (fPrevScanline != NULL && | |
82 fPrevScanline->fLastY + 1 == fCurrScanline->fLastY && | |
83 fPrevScanline->fXCount == fCurrScanline->fXCount && | |
84 !memcmp(fPrevScanline->firstX(), | |
85 fCurrScanline->firstX(), | |
86 fCurrScanline->fXCount * sizeof(SkRegion::RunType))) | |
87 { | |
88 // update the height of fPrevScanline | |
89 fPrevScanline->fLastY = fCurrScanline->fLastY; | |
90 return true; | |
91 } | |
92 return false; | |
93 } | |
94 }; | |
95 | |
96 SkRgnBuilder::~SkRgnBuilder() { | |
97 sk_free(fStorage); | |
98 } | |
99 | |
100 bool SkRgnBuilder::init(int maxHeight, int maxTransitions) { | |
101 if ((maxHeight | maxTransitions) < 0) { | |
102 return false; | |
103 } | |
104 | |
105 Sk64 count, size; | |
106 | |
107 // compute the count with +1 and +3 slop for the working buffer | |
108 count.setMul(maxHeight + 1, 3 + maxTransitions); | |
109 if (!count.is32() || count.isNeg()) { | |
110 return false; | |
111 } | |
112 fStorageCount = count.get32(); | |
113 | |
114 size.setMul(fStorageCount, sizeof(SkRegion::RunType)); | |
115 if (!size.is32() || size.isNeg()) { | |
116 return false; | |
117 } | |
118 | |
119 fStorage = (SkRegion::RunType*)sk_malloc_flags(size.get32(), 0); | |
120 if (NULL == fStorage) { | |
121 return false; | |
122 } | |
123 | |
124 fCurrScanline = NULL; // signal empty collection | |
125 fPrevScanline = NULL; // signal first scanline | |
126 return true; | |
127 } | |
128 | |
129 void SkRgnBuilder::blitH(int x, int y, int width) { | |
130 if (fCurrScanline == NULL) { // first time | |
131 fTop = (SkRegion::RunType)(y); | |
132 fCurrScanline = (Scanline*)fStorage; | |
133 fCurrScanline->fLastY = (SkRegion::RunType)(y); | |
134 fCurrXPtr = fCurrScanline->firstX(); | |
135 } else { | |
136 SkASSERT(y >= fCurrScanline->fLastY); | |
137 | |
138 if (y > fCurrScanline->fLastY) { | |
139 // if we get here, we're done with fCurrScanline | |
140 fCurrScanline->fXCount = (SkRegion::RunType)((int)(fCurrXPtr - fCurr
Scanline->firstX())); | |
141 | |
142 int prevLastY = fCurrScanline->fLastY; | |
143 if (!this->collapsWithPrev()) { | |
144 fPrevScanline = fCurrScanline; | |
145 fCurrScanline = fCurrScanline->nextScanline(); | |
146 | |
147 } | |
148 if (y - 1 > prevLastY) { // insert empty run | |
149 fCurrScanline->fLastY = (SkRegion::RunType)(y - 1); | |
150 fCurrScanline->fXCount = 0; | |
151 fCurrScanline = fCurrScanline->nextScanline(); | |
152 } | |
153 // setup for the new curr line | |
154 fCurrScanline->fLastY = (SkRegion::RunType)(y); | |
155 fCurrXPtr = fCurrScanline->firstX(); | |
156 } | |
157 } | |
158 // check if we should extend the current run, or add a new one | |
159 if (fCurrXPtr > fCurrScanline->firstX() && fCurrXPtr[-1] == x) { | |
160 fCurrXPtr[-1] = (SkRegion::RunType)(x + width); | |
161 } else { | |
162 fCurrXPtr[0] = (SkRegion::RunType)(x); | |
163 fCurrXPtr[1] = (SkRegion::RunType)(x + width); | |
164 fCurrXPtr += 2; | |
165 } | |
166 SkASSERT(fCurrXPtr - fStorage < fStorageCount); | |
167 } | |
168 | |
169 int SkRgnBuilder::computeRunCount() const { | |
170 if (fCurrScanline == NULL) { | |
171 return 0; | |
172 } | |
173 | |
174 const SkRegion::RunType* line = fStorage; | |
175 const SkRegion::RunType* stop = (const SkRegion::RunType*)fCurrScanline; | |
176 | |
177 return 2 + (int)(stop - line); | |
178 } | |
179 | |
180 void SkRgnBuilder::copyToRect(SkIRect* r) const { | |
181 SkASSERT(fCurrScanline != NULL); | |
182 SkASSERT((const SkRegion::RunType*)fCurrScanline - fStorage == 4); | |
183 | |
184 const Scanline* line = (const Scanline*)fStorage; | |
185 SkASSERT(line->fXCount == 2); | |
186 | |
187 r->set(line->firstX()[0], fTop, line->firstX()[1], line->fLastY + 1); | |
188 } | |
189 | |
190 void SkRgnBuilder::copyToRgn(SkRegion::RunType runs[]) const { | |
191 SkASSERT(fCurrScanline != NULL); | |
192 SkASSERT((const SkRegion::RunType*)fCurrScanline - fStorage > 4); | |
193 | |
194 const Scanline* line = (const Scanline*)fStorage; | |
195 const Scanline* stop = fCurrScanline; | |
196 | |
197 *runs++ = fTop; | |
198 do { | |
199 *runs++ = (SkRegion::RunType)(line->fLastY + 1); | |
200 int count = line->fXCount; | |
201 if (count) { | |
202 memcpy(runs, line->firstX(), count * sizeof(SkRegion::RunType)); | |
203 runs += count; | |
204 } | |
205 *runs++ = SkRegion::kRunTypeSentinel; | |
206 line = line->nextScanline(); | |
207 } while (line < stop); | |
208 SkASSERT(line == stop); | |
209 *runs = SkRegion::kRunTypeSentinel; | |
210 } | |
211 | |
212 static int count_path_runtype_values(const SkPath& path, int* itop, int* ibot) { | |
213 static const uint8_t gPathVerbToInitialLastIndex[] = { | |
214 0, // kMove_Verb | |
215 1, // kLine_Verb | |
216 2, // kQuad_Verb | |
217 3, // kCubic_Verb | |
218 0, // kClose_Verb | |
219 0 // kDone_Verb | |
220 }; | |
221 | |
222 static const uint8_t gPathVerbToMaxEdges[] = { | |
223 0, // kMove_Verb | |
224 1, // kLine_Verb | |
225 2, // kQuad_VerbB | |
226 3, // kCubic_Verb | |
227 0, // kClose_Verb | |
228 0 // kDone_Verb | |
229 }; | |
230 | |
231 SkPath::Iter iter(path, true); | |
232 SkPoint pts[4]; | |
233 SkPath::Verb verb; | |
234 | |
235 int maxEdges = 0; | |
236 SkScalar top = SkIntToScalar(SK_MaxS16); | |
237 SkScalar bot = SkIntToScalar(SK_MinS16); | |
238 | |
239 while ((verb = iter.next(pts)) != SkPath::kDone_Verb) { | |
240 maxEdges += gPathVerbToMaxEdges[verb]; | |
241 | |
242 int lastIndex = gPathVerbToInitialLastIndex[verb]; | |
243 if (lastIndex > 0) { | |
244 for (int i = 1; i <= lastIndex; i++) { | |
245 if (top > pts[i].fY) { | |
246 top = pts[i].fY; | |
247 } else if (bot < pts[i].fY) { | |
248 bot = pts[i].fY; | |
249 } | |
250 } | |
251 } else if (SkPath::kMove_Verb == verb) { | |
252 if (top > pts[0].fY) { | |
253 top = pts[0].fY; | |
254 } else if (bot < pts[0].fY) { | |
255 bot = pts[0].fY; | |
256 } | |
257 } | |
258 } | |
259 SkASSERT(top <= bot); | |
260 | |
261 *itop = SkScalarRound(top); | |
262 *ibot = SkScalarRound(bot); | |
263 return maxEdges; | |
264 } | |
265 | |
266 bool SkRegion::setPath(const SkPath& path, const SkRegion& clip) { | |
267 SkDEBUGCODE(this->validate();) | |
268 | |
269 if (clip.isEmpty()) { | |
270 return this->setEmpty(); | |
271 } | |
272 | |
273 if (path.isEmpty()) { | |
274 if (path.isInverseFillType()) { | |
275 return this->set(clip); | |
276 } else { | |
277 return this->setEmpty(); | |
278 } | |
279 } | |
280 | |
281 // compute worst-case rgn-size for the path | |
282 int pathTop, pathBot; | |
283 int pathTransitions = count_path_runtype_values(path, &pathTop, &pathBot); | |
284 int clipTop, clipBot; | |
285 int clipTransitions; | |
286 | |
287 clipTransitions = clip.count_runtype_values(&clipTop, &clipBot); | |
288 | |
289 int top = SkMax32(pathTop, clipTop); | |
290 int bot = SkMin32(pathBot, clipBot); | |
291 | |
292 if (top >= bot) | |
293 return this->setEmpty(); | |
294 | |
295 SkRgnBuilder builder; | |
296 | |
297 if (!builder.init(bot - top, SkMax32(pathTransitions, clipTransitions))) { | |
298 // can't allocate working space, so return false | |
299 return this->setEmpty(); | |
300 } | |
301 | |
302 SkScan::FillPath(path, clip, &builder); | |
303 builder.done(); | |
304 | |
305 int count = builder.computeRunCount(); | |
306 if (count == 0) { | |
307 return this->setEmpty(); | |
308 } else if (count == kRectRegionRuns) { | |
309 builder.copyToRect(&fBounds); | |
310 this->setRect(fBounds); | |
311 } else { | |
312 SkRegion tmp; | |
313 | |
314 tmp.fRunHead = RunHead::Alloc(count); | |
315 builder.copyToRgn(tmp.fRunHead->writable_runs()); | |
316 ComputeRunBounds(tmp.fRunHead->readonly_runs(), count, &tmp.fBounds); | |
317 this->swap(tmp); | |
318 } | |
319 SkDEBUGCODE(this->validate();) | |
320 return true; | |
321 } | |
322 | |
323 ////////////////////////////////////////////////////////////////////////////////
///////////////// | |
324 ////////////////////////////////////////////////////////////////////////////////
///////////////// | |
325 | |
326 struct Edge { | |
327 enum { | |
328 kY0Link = 0x01, | |
329 kY1Link = 0x02, | |
330 | |
331 kCompleteLink = (kY0Link | kY1Link) | |
332 }; | |
333 | |
334 SkRegion::RunType fX; | |
335 SkRegion::RunType fY0, fY1; | |
336 uint8_t fFlags; | |
337 Edge* fNext; | |
338 | |
339 void set(int x, int y0, int y1) { | |
340 SkASSERT(y0 != y1); | |
341 | |
342 fX = (SkRegion::RunType)(x); | |
343 fY0 = (SkRegion::RunType)(y0); | |
344 fY1 = (SkRegion::RunType)(y1); | |
345 fFlags = 0; | |
346 SkDEBUGCODE(fNext = NULL;) | |
347 } | |
348 | |
349 int top() const { | |
350 return SkFastMin32(fY0, fY1); | |
351 } | |
352 }; | |
353 | |
354 static void find_link(Edge* base, Edge* stop) { | |
355 SkASSERT(base < stop); | |
356 | |
357 if (base->fFlags == Edge::kCompleteLink) { | |
358 SkASSERT(base->fNext); | |
359 return; | |
360 } | |
361 | |
362 SkASSERT(base + 1 < stop); | |
363 | |
364 int y0 = base->fY0; | |
365 int y1 = base->fY1; | |
366 | |
367 Edge* e = base; | |
368 if ((base->fFlags & Edge::kY0Link) == 0) { | |
369 for (;;) { | |
370 e += 1; | |
371 if ((e->fFlags & Edge::kY1Link) == 0 && y0 == e->fY1) { | |
372 SkASSERT(NULL == e->fNext); | |
373 e->fNext = base; | |
374 e->fFlags = SkToU8(e->fFlags | Edge::kY1Link); | |
375 break; | |
376 } | |
377 } | |
378 } | |
379 | |
380 e = base; | |
381 if ((base->fFlags & Edge::kY1Link) == 0) { | |
382 for (;;) { | |
383 e += 1; | |
384 if ((e->fFlags & Edge::kY0Link) == 0 && y1 == e->fY0) { | |
385 SkASSERT(NULL == base->fNext); | |
386 base->fNext = e; | |
387 e->fFlags = SkToU8(e->fFlags | Edge::kY0Link); | |
388 break; | |
389 } | |
390 } | |
391 } | |
392 | |
393 base->fFlags = Edge::kCompleteLink; | |
394 } | |
395 | |
396 static int extract_path(Edge* edge, Edge* stop, SkPath* path) { | |
397 while (0 == edge->fFlags) { | |
398 edge++; // skip over "used" edges | |
399 } | |
400 | |
401 SkASSERT(edge < stop); | |
402 | |
403 Edge* base = edge; | |
404 Edge* prev = edge; | |
405 edge = edge->fNext; | |
406 SkASSERT(edge != base); | |
407 | |
408 int count = 1; | |
409 path->moveTo(SkIntToScalar(prev->fX), SkIntToScalar(prev->fY0)); | |
410 prev->fFlags = 0; | |
411 do { | |
412 if (prev->fX != edge->fX || prev->fY1 != edge->fY0) { // skip collinear | |
413 path->lineTo(SkIntToScalar(prev->fX), SkIntToScalar(prev->fY1));
// V | |
414 path->lineTo(SkIntToScalar(edge->fX), SkIntToScalar(edge->fY0));
// H | |
415 } | |
416 prev = edge; | |
417 edge = edge->fNext; | |
418 count += 1; | |
419 prev->fFlags = 0; | |
420 } while (edge != base); | |
421 path->lineTo(SkIntToScalar(prev->fX), SkIntToScalar(prev->fY1)); // V | |
422 path->close(); | |
423 return count; | |
424 } | |
425 | |
426 #include "SkTSearch.h" | |
427 | |
428 static int EdgeProc(const Edge* a, const Edge* b) { | |
429 return (a->fX == b->fX) ? a->top() - b->top() : a->fX - b->fX; | |
430 } | |
431 | |
432 bool SkRegion::getBoundaryPath(SkPath* path) const { | |
433 if (this->isEmpty()) { | |
434 return false; | |
435 } | |
436 | |
437 const SkIRect& bounds = this->getBounds(); | |
438 | |
439 if (this->isRect()) { | |
440 SkRect r; | |
441 r.set(bounds); // this converts the ints to scalars | |
442 path->addRect(r); | |
443 return true; | |
444 } | |
445 | |
446 SkRegion::Iterator iter(*this); | |
447 SkTDArray<Edge> edges; | |
448 | |
449 for (const SkIRect& r = iter.rect(); !iter.done(); iter.next()) { | |
450 Edge* edge = edges.append(2); | |
451 edge[0].set(r.fLeft, r.fBottom, r.fTop); | |
452 edge[1].set(r.fRight, r.fTop, r.fBottom); | |
453 } | |
454 SkQSort(edges.begin(), edges.count(), sizeof(Edge), (SkQSortCompareProc)Edge
Proc); | |
455 | |
456 int count = edges.count(); | |
457 Edge* start = edges.begin(); | |
458 Edge* stop = start + count; | |
459 Edge* e; | |
460 | |
461 for (e = start; e != stop; e++) { | |
462 find_link(e, stop); | |
463 } | |
464 | |
465 #ifdef SK_DEBUG | |
466 for (e = start; e != stop; e++) { | |
467 SkASSERT(e->fNext != NULL); | |
468 SkASSERT(e->fFlags == Edge::kCompleteLink); | |
469 } | |
470 #endif | |
471 | |
472 path->incReserve(count << 1); | |
473 do { | |
474 SkASSERT(count > 1); | |
475 count -= extract_path(start, stop, path); | |
476 } while (count > 0); | |
477 | |
478 return true; | |
479 } | |
480 | |
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