src/third_party/skia/src/core/SkPathRef.cpp

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