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1 /*
2  * Copyright 2013 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #include "SkBuffer.h"
9 #include "SkLazyPtr.h"
10 #include "SkPath.h"
11 #include "SkPathRef.h"
12 
13 //////////////////////////////////////////////////////////////////////////////
Editor(SkAutoTUnref<SkPathRef> * pathRef,int incReserveVerbs,int incReservePoints)14 SkPathRef::Editor::Editor(SkAutoTUnref<SkPathRef>* pathRef,
15                           int incReserveVerbs,
16                           int incReservePoints)
17 {
18     if ((*pathRef)->unique()) {
19         (*pathRef)->incReserve(incReserveVerbs, incReservePoints);
20     } else {
21         SkPathRef* copy = SkNEW(SkPathRef);
22         copy->copy(**pathRef, incReserveVerbs, incReservePoints);
23         pathRef->reset(copy);
24     }
25     fPathRef = *pathRef;
26     fPathRef->fGenerationID = 0;
27     SkDEBUGCODE(sk_atomic_inc(&fPathRef->fEditorsAttached);)
28 }
29 
30 //////////////////////////////////////////////////////////////////////////////
31 
CreateEmptyImpl()32 SkPathRef* SkPathRef::CreateEmptyImpl() {
33     SkPathRef* empty = SkNEW(SkPathRef);
34     empty->computeBounds();   // Avoids races later to be the first to do this.
35     return empty;
36 }
37 
CreateEmpty()38 SkPathRef* SkPathRef::CreateEmpty() {
39     SK_DECLARE_STATIC_LAZY_PTR(SkPathRef, empty, CreateEmptyImpl);
40     return SkRef(empty.get());
41 }
42 
CreateTransformedCopy(SkAutoTUnref<SkPathRef> * dst,const SkPathRef & src,const SkMatrix & matrix)43 void SkPathRef::CreateTransformedCopy(SkAutoTUnref<SkPathRef>* dst,
44                                       const SkPathRef& src,
45                                       const SkMatrix& matrix) {
46     SkDEBUGCODE(src.validate();)
47     if (matrix.isIdentity()) {
48         if (*dst != &src) {
49             src.ref();
50             dst->reset(const_cast<SkPathRef*>(&src));
51             SkDEBUGCODE((*dst)->validate();)
52         }
53         return;
54     }
55 
56     if (!(*dst)->unique()) {
57         dst->reset(SkNEW(SkPathRef));
58     }
59 
60     if (*dst != &src) {
61         (*dst)->resetToSize(src.fVerbCnt, src.fPointCnt, src.fConicWeights.count());
62         memcpy((*dst)->verbsMemWritable(), src.verbsMemBegin(), src.fVerbCnt * sizeof(uint8_t));
63         (*dst)->fConicWeights = src.fConicWeights;
64     }
65 
66     SkASSERT((*dst)->countPoints() == src.countPoints());
67     SkASSERT((*dst)->countVerbs() == src.countVerbs());
68     SkASSERT((*dst)->fConicWeights.count() == src.fConicWeights.count());
69 
70     // Need to check this here in case (&src == dst)
71     bool canXformBounds = !src.fBoundsIsDirty && matrix.rectStaysRect() && src.countPoints() > 1;
72 
73     matrix.mapPoints((*dst)->fPoints, src.points(), src.fPointCnt);
74 
75     /*
76         *  Here we optimize the bounds computation, by noting if the bounds are
77         *  already known, and if so, we just transform those as well and mark
78         *  them as "known", rather than force the transformed path to have to
79         *  recompute them.
80         *
81         *  Special gotchas if the path is effectively empty (<= 1 point) or
82         *  if it is non-finite. In those cases bounds need to stay empty,
83         *  regardless of the matrix.
84         */
85     if (canXformBounds) {
86         (*dst)->fBoundsIsDirty = false;
87         if (src.fIsFinite) {
88             matrix.mapRect((*dst)->fBounds.get(), src.fBounds);
89             if (!((*dst)->fIsFinite = (*dst)->fBounds->isFinite())) {
90                 (*dst)->fBounds->setEmpty();
91             }
92         } else {
93             (*dst)->fIsFinite = false;
94             (*dst)->fBounds->setEmpty();
95         }
96     } else {
97         (*dst)->fBoundsIsDirty = true;
98     }
99 
100     (*dst)->fSegmentMask = src.fSegmentMask;
101 
102     // It's an oval only if it stays a rect.
103     (*dst)->fIsOval = src.fIsOval && matrix.rectStaysRect();
104 
105     SkDEBUGCODE((*dst)->validate();)
106 }
107 
CreateFromBuffer(SkRBuffer * buffer)108 SkPathRef* SkPathRef::CreateFromBuffer(SkRBuffer* buffer) {
109     SkPathRef* ref = SkNEW(SkPathRef);
110     bool isOval;
111     uint8_t segmentMask;
112 
113     int32_t packed;
114     if (!buffer->readS32(&packed)) {
115         SkDELETE(ref);
116         return NULL;
117     }
118 
119     ref->fIsFinite = (packed >> kIsFinite_SerializationShift) & 1;
120     segmentMask = (packed >> kSegmentMask_SerializationShift) & 0xF;
121     isOval  = (packed >> kIsOval_SerializationShift) & 1;
122 
123     int32_t verbCount, pointCount, conicCount;
124     if (!buffer->readU32(&(ref->fGenerationID)) ||
125         !buffer->readS32(&verbCount) ||
126         !buffer->readS32(&pointCount) ||
127         !buffer->readS32(&conicCount)) {
128         SkDELETE(ref);
129         return NULL;
130     }
131 
132     ref->resetToSize(verbCount, pointCount, conicCount);
133     SkASSERT(verbCount == ref->countVerbs());
134     SkASSERT(pointCount == ref->countPoints());
135     SkASSERT(conicCount == ref->fConicWeights.count());
136 
137     if (!buffer->read(ref->verbsMemWritable(), verbCount * sizeof(uint8_t)) ||
138         !buffer->read(ref->fPoints, pointCount * sizeof(SkPoint)) ||
139         !buffer->read(ref->fConicWeights.begin(), conicCount * sizeof(SkScalar)) ||
140         !buffer->read(&ref->fBounds, sizeof(SkRect))) {
141         SkDELETE(ref);
142         return NULL;
143     }
144     ref->fBoundsIsDirty = false;
145 
146     // resetToSize clears fSegmentMask and fIsOval
147     ref->fSegmentMask = segmentMask;
148     ref->fIsOval = isOval;
149     return ref;
150 }
151 
Rewind(SkAutoTUnref<SkPathRef> * pathRef)152 void SkPathRef::Rewind(SkAutoTUnref<SkPathRef>* pathRef) {
153     if ((*pathRef)->unique()) {
154         SkDEBUGCODE((*pathRef)->validate();)
155         (*pathRef)->fBoundsIsDirty = true;  // this also invalidates fIsFinite
156         (*pathRef)->fVerbCnt = 0;
157         (*pathRef)->fPointCnt = 0;
158         (*pathRef)->fFreeSpace = (*pathRef)->currSize();
159         (*pathRef)->fGenerationID = 0;
160         (*pathRef)->fConicWeights.rewind();
161         (*pathRef)->fSegmentMask = 0;
162         (*pathRef)->fIsOval = false;
163         SkDEBUGCODE((*pathRef)->validate();)
164     } else {
165         int oldVCnt = (*pathRef)->countVerbs();
166         int oldPCnt = (*pathRef)->countPoints();
167         pathRef->reset(SkNEW(SkPathRef));
168         (*pathRef)->resetToSize(0, 0, 0, oldVCnt, oldPCnt);
169     }
170 }
171 
operator ==(const SkPathRef & ref) const172 bool SkPathRef::operator== (const SkPathRef& ref) const {
173     SkDEBUGCODE(this->validate();)
174     SkDEBUGCODE(ref.validate();)
175 
176     // We explicitly check fSegmentMask as a quick-reject. We could skip it,
177     // since it is only a cache of info in the fVerbs, but its a fast way to
178     // notice a difference
179     if (fSegmentMask != ref.fSegmentMask) {
180         return false;
181     }
182 
183     bool genIDMatch = fGenerationID && fGenerationID == ref.fGenerationID;
184 #ifdef SK_RELEASE
185     if (genIDMatch) {
186         return true;
187     }
188 #endif
189     if (fPointCnt != ref.fPointCnt ||
190         fVerbCnt != ref.fVerbCnt) {
191         SkASSERT(!genIDMatch);
192         return false;
193     }
194     if (0 != memcmp(this->verbsMemBegin(),
195                     ref.verbsMemBegin(),
196                     ref.fVerbCnt * sizeof(uint8_t))) {
197         SkASSERT(!genIDMatch);
198         return false;
199     }
200     if (0 != memcmp(this->points(),
201                     ref.points(),
202                     ref.fPointCnt * sizeof(SkPoint))) {
203         SkASSERT(!genIDMatch);
204         return false;
205     }
206     if (fConicWeights != ref.fConicWeights) {
207         SkASSERT(!genIDMatch);
208         return false;
209     }
210     // We've done the work to determine that these are equal. If either has a zero genID, copy
211     // the other's. If both are 0 then genID() will compute the next ID.
212     if (0 == fGenerationID) {
213         fGenerationID = ref.genID();
214     } else if (0 == ref.fGenerationID) {
215         ref.fGenerationID = this->genID();
216     }
217     return true;
218 }
219 
writeToBuffer(SkWBuffer * buffer) const220 void SkPathRef::writeToBuffer(SkWBuffer* buffer) const {
221     SkDEBUGCODE(this->validate();)
222     SkDEBUGCODE(size_t beforePos = buffer->pos();)
223 
224     // Call getBounds() to ensure (as a side-effect) that fBounds
225     // and fIsFinite are computed.
226     const SkRect& bounds = this->getBounds();
227 
228     int32_t packed = ((fIsFinite & 1) << kIsFinite_SerializationShift) |
229                      ((fIsOval & 1) << kIsOval_SerializationShift) |
230                      (fSegmentMask << kSegmentMask_SerializationShift);
231     buffer->write32(packed);
232 
233     // TODO: write gen ID here. Problem: We don't know if we're cross process or not from
234     // SkWBuffer. Until this is fixed we write 0.
235     buffer->write32(0);
236     buffer->write32(fVerbCnt);
237     buffer->write32(fPointCnt);
238     buffer->write32(fConicWeights.count());
239     buffer->write(verbsMemBegin(), fVerbCnt * sizeof(uint8_t));
240     buffer->write(fPoints, fPointCnt * sizeof(SkPoint));
241     buffer->write(fConicWeights.begin(), fConicWeights.bytes());
242     buffer->write(&bounds, sizeof(bounds));
243 
244     SkASSERT(buffer->pos() - beforePos == (size_t) this->writeSize());
245 }
246 
writeSize() const247 uint32_t SkPathRef::writeSize() const {
248     return uint32_t(5 * sizeof(uint32_t) +
249                     fVerbCnt * sizeof(uint8_t) +
250                     fPointCnt * sizeof(SkPoint) +
251                     fConicWeights.bytes() +
252                     sizeof(SkRect));
253 }
254 
copy(const SkPathRef & ref,int additionalReserveVerbs,int additionalReservePoints)255 void SkPathRef::copy(const SkPathRef& ref,
256                      int additionalReserveVerbs,
257                      int additionalReservePoints) {
258     SkDEBUGCODE(this->validate();)
259     this->resetToSize(ref.fVerbCnt, ref.fPointCnt, ref.fConicWeights.count(),
260                         additionalReserveVerbs, additionalReservePoints);
261     memcpy(this->verbsMemWritable(), ref.verbsMemBegin(), ref.fVerbCnt * sizeof(uint8_t));
262     memcpy(this->fPoints, ref.fPoints, ref.fPointCnt * sizeof(SkPoint));
263     fConicWeights = ref.fConicWeights;
264     // We could call genID() here to force a real ID (instead of 0). However, if we're making
265     // a copy then presumably we intend to make a modification immediately afterwards.
266     fGenerationID = ref.fGenerationID;
267     fBoundsIsDirty = ref.fBoundsIsDirty;
268     if (!fBoundsIsDirty) {
269         fBounds = ref.fBounds;
270         fIsFinite = ref.fIsFinite;
271     }
272     fSegmentMask = ref.fSegmentMask;
273     fIsOval = ref.fIsOval;
274     SkDEBUGCODE(this->validate();)
275 }
276 
growForRepeatedVerb(int verb,int numVbs,SkScalar ** weights)277 SkPoint* SkPathRef::growForRepeatedVerb(int /*SkPath::Verb*/ verb,
278                                         int numVbs,
279                                         SkScalar** weights) {
280     // This value is just made-up for now. When count is 4, calling memset was much
281     // slower than just writing the loop. This seems odd, and hopefully in the
282     // future this will appear to have been a fluke...
283     static const unsigned int kMIN_COUNT_FOR_MEMSET_TO_BE_FAST = 16;
284 
285     SkDEBUGCODE(this->validate();)
286     int pCnt;
287     bool dirtyAfterEdit = true;
288     switch (verb) {
289         case SkPath::kMove_Verb:
290             pCnt = numVbs;
291             dirtyAfterEdit = false;
292             break;
293         case SkPath::kLine_Verb:
294             fSegmentMask |= SkPath::kLine_SegmentMask;
295             pCnt = numVbs;
296             break;
297         case SkPath::kQuad_Verb:
298             fSegmentMask |= SkPath::kQuad_SegmentMask;
299             pCnt = 2 * numVbs;
300             break;
301         case SkPath::kConic_Verb:
302             fSegmentMask |= SkPath::kConic_SegmentMask;
303             pCnt = 2 * numVbs;
304             break;
305         case SkPath::kCubic_Verb:
306             fSegmentMask |= SkPath::kCubic_SegmentMask;
307             pCnt = 3 * numVbs;
308             break;
309         case SkPath::kClose_Verb:
310             SkDEBUGFAIL("growForRepeatedVerb called for kClose_Verb");
311             pCnt = 0;
312             dirtyAfterEdit = false;
313             break;
314         case SkPath::kDone_Verb:
315             SkDEBUGFAIL("growForRepeatedVerb called for kDone");
316             // fall through
317         default:
318             SkDEBUGFAIL("default should not be reached");
319             pCnt = 0;
320             dirtyAfterEdit = false;
321     }
322 
323     size_t space = numVbs * sizeof(uint8_t) + pCnt * sizeof (SkPoint);
324     this->makeSpace(space);
325 
326     SkPoint* ret = fPoints + fPointCnt;
327     uint8_t* vb = fVerbs - fVerbCnt;
328 
329     // cast to unsigned, so if kMIN_COUNT_FOR_MEMSET_TO_BE_FAST is defined to
330     // be 0, the compiler will remove the test/branch entirely.
331     if ((unsigned)numVbs >= kMIN_COUNT_FOR_MEMSET_TO_BE_FAST) {
332         memset(vb - numVbs, verb, numVbs);
333     } else {
334         for (int i = 0; i < numVbs; ++i) {
335             vb[~i] = verb;
336         }
337     }
338 
339     fVerbCnt += numVbs;
340     fPointCnt += pCnt;
341     fFreeSpace -= space;
342     fBoundsIsDirty = true;  // this also invalidates fIsFinite
343     if (dirtyAfterEdit) {
344         fIsOval = false;
345     }
346 
347     if (SkPath::kConic_Verb == verb) {
348         SkASSERT(weights);
349         *weights = fConicWeights.append(numVbs);
350     }
351 
352     SkDEBUGCODE(this->validate();)
353     return ret;
354 }
355 
growForVerb(int verb,SkScalar weight)356 SkPoint* SkPathRef::growForVerb(int /* SkPath::Verb*/ verb, SkScalar weight) {
357     SkDEBUGCODE(this->validate();)
358     int pCnt;
359     bool dirtyAfterEdit = true;
360     switch (verb) {
361         case SkPath::kMove_Verb:
362             pCnt = 1;
363             dirtyAfterEdit = false;
364             break;
365         case SkPath::kLine_Verb:
366             fSegmentMask |= SkPath::kLine_SegmentMask;
367             pCnt = 1;
368             break;
369         case SkPath::kQuad_Verb:
370             fSegmentMask |= SkPath::kQuad_SegmentMask;
371             pCnt = 2;
372             break;
373         case SkPath::kConic_Verb:
374             fSegmentMask |= SkPath::kConic_SegmentMask;
375             pCnt = 2;
376             break;
377         case SkPath::kCubic_Verb:
378             fSegmentMask |= SkPath::kCubic_SegmentMask;
379             pCnt = 3;
380             break;
381         case SkPath::kClose_Verb:
382             pCnt = 0;
383             dirtyAfterEdit = false;
384             break;
385         case SkPath::kDone_Verb:
386             SkDEBUGFAIL("growForVerb called for kDone");
387             // fall through
388         default:
389             SkDEBUGFAIL("default is not reached");
390             dirtyAfterEdit = false;
391             pCnt = 0;
392     }
393     size_t space = sizeof(uint8_t) + pCnt * sizeof (SkPoint);
394     this->makeSpace(space);
395     this->fVerbs[~fVerbCnt] = verb;
396     SkPoint* ret = fPoints + fPointCnt;
397     fVerbCnt += 1;
398     fPointCnt += pCnt;
399     fFreeSpace -= space;
400     fBoundsIsDirty = true;  // this also invalidates fIsFinite
401     if (dirtyAfterEdit) {
402         fIsOval = false;
403     }
404 
405     if (SkPath::kConic_Verb == verb) {
406         *fConicWeights.append() = weight;
407     }
408 
409     SkDEBUGCODE(this->validate();)
410     return ret;
411 }
412 
genID() const413 uint32_t SkPathRef::genID() const {
414     SkASSERT(!fEditorsAttached);
415     static const uint32_t kMask = (static_cast<int64_t>(1) << SkPath::kPathRefGenIDBitCnt) - 1;
416     if (!fGenerationID) {
417         if (0 == fPointCnt && 0 == fVerbCnt) {
418             fGenerationID = kEmptyGenID;
419         } else {
420             static int32_t  gPathRefGenerationID;
421             // do a loop in case our global wraps around, as we never want to return a 0 or the
422             // empty ID
423             do {
424                 fGenerationID = (sk_atomic_inc(&gPathRefGenerationID) + 1) & kMask;
425             } while (fGenerationID <= kEmptyGenID);
426         }
427     }
428     return fGenerationID;
429 }
430 
431 #ifdef SK_DEBUG
validate() const432 void SkPathRef::validate() const {
433     this->INHERITED::validate();
434     SkASSERT(static_cast<ptrdiff_t>(fFreeSpace) >= 0);
435     SkASSERT(reinterpret_cast<intptr_t>(fVerbs) - reinterpret_cast<intptr_t>(fPoints) >= 0);
436     SkASSERT((NULL == fPoints) == (NULL == fVerbs));
437     SkASSERT(!(NULL == fPoints && 0 != fFreeSpace));
438     SkASSERT(!(NULL == fPoints && 0 != fFreeSpace));
439     SkASSERT(!(NULL == fPoints && fPointCnt));
440     SkASSERT(!(NULL == fVerbs && fVerbCnt));
441     SkASSERT(this->currSize() ==
442                 fFreeSpace + sizeof(SkPoint) * fPointCnt + sizeof(uint8_t) * fVerbCnt);
443 
444     if (!fBoundsIsDirty && !fBounds->isEmpty()) {
445         bool isFinite = true;
446         for (int i = 0; i < fPointCnt; ++i) {
447             SkASSERT(!fPoints[i].isFinite() || (
448                      fBounds->fLeft - fPoints[i].fX   < SK_ScalarNearlyZero &&
449                      fPoints[i].fX - fBounds->fRight  < SK_ScalarNearlyZero &&
450                      fBounds->fTop  - fPoints[i].fY   < SK_ScalarNearlyZero &&
451                      fPoints[i].fY - fBounds->fBottom < SK_ScalarNearlyZero));
452             if (!fPoints[i].isFinite()) {
453                 isFinite = false;
454             }
455         }
456         SkASSERT(SkToBool(fIsFinite) == isFinite);
457     }
458 
459 #ifdef SK_DEBUG_PATH
460     uint32_t mask = 0;
461     for (int i = 0; i < fVerbCnt; ++i) {
462         switch (fVerbs[~i]) {
463             case SkPath::kMove_Verb:
464                 break;
465             case SkPath::kLine_Verb:
466                 mask |= SkPath::kLine_SegmentMask;
467                 break;
468             case SkPath::kQuad_Verb:
469                 mask |= SkPath::kQuad_SegmentMask;
470                 break;
471             case SkPath::kConic_Verb:
472                 mask |= SkPath::kConic_SegmentMask;
473                 break;
474             case SkPath::kCubic_Verb:
475                 mask |= SkPath::kCubic_SegmentMask;
476                 break;
477             case SkPath::kClose_Verb:
478                 break;
479             case SkPath::kDone_Verb:
480                 SkDEBUGFAIL("Done verb shouldn't be recorded.");
481                 break;
482             default:
483                 SkDEBUGFAIL("Unknown Verb");
484                 break;
485         }
486     }
487     SkASSERT(mask == fSegmentMask);
488 #endif // SK_DEBUG_PATH
489 }
490 #endif
491