cumulative pathops patch

Replace the implicit curve intersection with a geometric curve intersection. The implicit intersection proved mathematically unstable and took a long time to zero in on an answer.

Use pointers instead of indices to refer to parts of curves. Indices required awkward renumbering.

Unify t and point values so that small intervals can be eliminated in one pass.

Break cubics up front to eliminate loops and cusps.

Make the Simplify and Op code more regular and eliminate arbitrary differences.

Add a builder that takes an array of paths and operators.

Delete unused code.

BUG=skia:3588
R=reed@google.com

Review URL: https://codereview.chromium.org/1037573004

1 files changed, 388 insertions, 0 deletions

diff --git a/src/pathops/SkOpCoincidence.cpp b/src/pathops/SkOpCoincidence.cpp
new file mode 100755
index 0000000000..45eee0a38e
--- /dev/null
+++ b/src/pathops/SkOpCoincidence.cpp
@@ -0,0 +1,388 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+#include "SkOpCoincidence.h"
+#include "SkOpSegment.h"
+#include "SkPathOpsTSect.h"
+
+void SkOpCoincidence::add(SkOpPtT* coinPtTStart, SkOpPtT* coinPtTEnd, SkOpPtT* oppPtTStart,
+        SkOpPtT* oppPtTEnd, SkChunkAlloc* allocator) {
+    SkASSERT(coinPtTStart->fT < coinPtTEnd->fT);
+    bool flipped = oppPtTStart->fT > oppPtTEnd->fT;
+    SkCoincidentSpans* coinRec = SkOpTAllocator<SkCoincidentSpans>::Allocate(allocator);
+    coinRec->fNext = this->fHead;
+    coinRec->fCoinPtTStart = coinPtTStart;
+    coinRec->fCoinPtTEnd = coinPtTEnd;
+    coinRec->fOppPtTStart = oppPtTStart;
+    coinRec->fOppPtTEnd = oppPtTEnd;
+    coinRec->fFlipped = flipped;
+    this->fHead = coinRec;
+}
+
+static void tRange(const SkOpPtT* overS, const SkOpPtT* overE, double tStart, double tEnd,
+        const SkOpPtT* coinPtTStart, const SkOpPtT* coinPtTEnd, double* coinTs, double* coinTe) {
+    double denom = overE->fT - overS->fT;
+    double start = 0 < denom ? tStart : tEnd;
+    double end = 0 < denom ? tEnd : tStart;
+    double sRatio = (start - overS->fT) / denom;
+    double eRatio = (end - overS->fT) / denom;
+    *coinTs = coinPtTStart->fT + (coinPtTEnd->fT - coinPtTStart->fT) * sRatio;
+    *coinTe = coinPtTStart->fT + (coinPtTEnd->fT - coinPtTStart->fT) * eRatio;
+}
+
+bool SkOpCoincidence::addIfMissing(const SkOpPtT* over1s, const SkOpPtT* over1e,
+                      const SkOpPtT* over2s, const SkOpPtT* over2e, double tStart, double tEnd,
+        SkOpPtT* coinPtTStart, const SkOpPtT* coinPtTEnd,
+        SkOpPtT* oppPtTStart, const SkOpPtT* oppPtTEnd, SkChunkAlloc* allocator) {
+    double coinTs, coinTe, oppTs, oppTe;
+    tRange(over1s, over1e, tStart, tEnd, coinPtTStart, coinPtTEnd, &coinTs, &coinTe);
+    tRange(over2s, over2e, tStart, tEnd, oppPtTStart, oppPtTEnd, &oppTs, &oppTe);
+    SkOpSegment* coinSeg = coinPtTStart->segment();
+    SkOpSegment* oppSeg = oppPtTStart->segment();
+    SkASSERT(coinSeg != oppSeg);
+    SkCoincidentSpans* check = this->fHead;
+    do {
+        const SkOpSegment* checkCoinSeg = check->fCoinPtTStart->segment();
+        if (checkCoinSeg != coinSeg && checkCoinSeg != oppSeg) {
+            continue;
+        }
+        const SkOpSegment* checkOppSeg = check->fOppPtTStart->segment();
+        if (checkOppSeg != coinSeg && checkOppSeg != oppSeg) {
+            continue;
+        }
+        int cTs = coinTs;
+        int cTe = coinTe;
+        int oTs = oppTs;
+        int oTe = oppTe;
+        if (checkCoinSeg != coinSeg) {
+            SkASSERT(checkOppSeg != oppSeg);
+            SkTSwap(cTs, oTs);
+            SkTSwap(cTe, oTe);
+        }
+        int tweenCount = (int) between(check->fCoinPtTStart->fT, cTs, check->fCoinPtTEnd->fT)
+                       + (int) between(check->fCoinPtTStart->fT, cTe, check->fCoinPtTEnd->fT)
+                       + (int) between(check->fOppPtTStart->fT, oTs, check->fOppPtTEnd->fT)
+                       + (int) between(check->fOppPtTStart->fT, oTe, check->fOppPtTEnd->fT);
+//        SkASSERT(tweenCount == 0 || tweenCount == 4);
+        if (tweenCount) {
+            return true;
+        }
+    } while ((check = check->fNext));
+    if ((over1s->fT < over1e->fT) != (over2s->fT < over2e->fT)) {
+        SkTSwap(oppTs, oppTe);
+    }
+    if (coinTs > coinTe) {
+        SkTSwap(coinTs, coinTe);
+        SkTSwap(oppTs, oppTe);
+    }
+    SkOpPtT* cs = coinSeg->addMissing(coinTs, oppSeg, allocator);
+    SkOpPtT* ce = coinSeg->addMissing(coinTe, oppSeg, allocator);
+    if (cs == ce) {
+        return false;
+    }
+    SkOpPtT* os = oppSeg->addMissing(oppTs, coinSeg, allocator);
+    SkOpPtT* oe = oppSeg->addMissing(oppTe, coinSeg, allocator);
+    SkASSERT(os != oe);
+    cs->addOpp(os);
+    ce->addOpp(oe);
+    this->add(cs, ce, os, oe, allocator);
+    return true;
+}
+
+bool SkOpCoincidence::addMissing(SkChunkAlloc* allocator) {
+    SkCoincidentSpans* outer = this->fHead;
+    if (!outer) {
+        return true;
+    }
+    do {
+        SkCoincidentSpans* inner = outer;
+        while ((inner = inner->fNext)) {
+            double overS, overE;
+            if (this->overlap(outer->fCoinPtTStart, outer->fCoinPtTEnd,
+                    inner->fCoinPtTStart, inner->fCoinPtTEnd, &overS, &overE)) {
+                if (!addIfMissing(outer->fCoinPtTStart, outer->fCoinPtTEnd,
+                        inner->fCoinPtTStart, inner->fCoinPtTEnd, overS, overE,
+                        outer->fOppPtTStart, outer->fOppPtTEnd,
+                        inner->fOppPtTStart, inner->fOppPtTEnd, allocator)) {
+                    return false;
+                }
+            } else if (this->overlap(outer->fCoinPtTStart, outer->fCoinPtTEnd,
+                    inner->fOppPtTStart, inner->fOppPtTEnd, &overS, &overE)) {
+                if (!addIfMissing(outer->fCoinPtTStart, outer->fCoinPtTEnd,
+                        inner->fOppPtTStart, inner->fOppPtTEnd, overS, overE,
+                        outer->fOppPtTStart, outer->fOppPtTEnd,
+                        inner->fCoinPtTStart, inner->fCoinPtTEnd, allocator)) {
+                    return false;
+                }
+            } else if (this->overlap(outer->fOppPtTStart, outer->fOppPtTEnd,
+                    inner->fCoinPtTStart, inner->fCoinPtTEnd, &overS, &overE)) {
+                if (!addIfMissing(outer->fOppPtTStart, outer->fOppPtTEnd,
+                        inner->fCoinPtTStart, inner->fCoinPtTEnd, overS, overE,
+                        outer->fCoinPtTStart, outer->fCoinPtTEnd,
+                        inner->fOppPtTStart, inner->fOppPtTEnd, allocator)) {
+                    return false;
+                }
+            } else if (this->overlap(outer->fOppPtTStart, outer->fOppPtTEnd,
+                    inner->fOppPtTStart, inner->fOppPtTEnd, &overS, &overE)) {
+                if (!addIfMissing(outer->fOppPtTStart, outer->fOppPtTEnd,
+                        inner->fOppPtTStart, inner->fOppPtTEnd, overS, overE,
+                        outer->fCoinPtTStart, outer->fCoinPtTEnd,
+                        inner->fCoinPtTStart, inner->fCoinPtTEnd, allocator)) {
+                    return false;
+                }
+            }
+        }
+
+    } while ((outer = outer->fNext));
+    return true;
+}
+
+
+bool SkOpCoincidence::contains(SkOpPtT* coinPtTStart, SkOpPtT* coinPtTEnd, SkOpPtT* oppPtTStart,
+        SkOpPtT* oppPtTEnd, bool flipped) {
+    SkCoincidentSpans* coin = fHead;
+    if (!coin) {
+        return false;
+    }
+    do {
+        if (coin->fCoinPtTStart == coinPtTStart &&  coin->fCoinPtTEnd == coinPtTEnd
+                && coin->fOppPtTStart == oppPtTStart && coin->fOppPtTEnd == oppPtTEnd
+                && coin->fFlipped == flipped) {
+            return true;
+        }
+    } while ((coin = coin->fNext));
+    return false;
+}
+
+// walk span sets in parallel, moving winding from one to the other
+bool SkOpCoincidence::apply() {
+    SkCoincidentSpans* coin = fHead;
+    if (!coin) {
+        return true;
+    }
+    do {
+        SkOpSpanBase* end = coin->fCoinPtTEnd->span();
+        SkOpSpan* start = coin->fCoinPtTStart->span()->upCast();
+        SkASSERT(start == start->starter(end));
+        bool flipped = coin->fFlipped;
+        SkOpSpanBase* oEnd = (flipped ? coin->fOppPtTStart : coin->fOppPtTEnd)->span();
+        SkOpSpan* oStart = (flipped ? coin->fOppPtTEnd : coin->fOppPtTStart)->span()->upCast();
+        SkASSERT(oStart == oStart->starter(oEnd));
+        SkOpSegment* segment = start->segment();
+        SkOpSegment* oSegment = oStart->segment();
+        bool operandSwap = segment->operand() != oSegment->operand();
+        if (flipped) {
+            do {
+                SkOpSpanBase* oNext = oStart->next();
+                if (oNext == oEnd) {
+                    break;
+                }
+                oStart = oNext->upCast();
+            } while (true);
+        }
+        bool isXor = segment->isXor();
+        bool oppXor = oSegment->isXor();
+        do {
+            int windValue = start->windValue();
+            int oWindValue = oStart->windValue();
+            int oppValue = start->oppValue();
+            int oOppValue = oStart->oppValue();
+            // winding values are added or subtracted depending on direction and wind type
+            // same or opposite values are summed depending on the operand value
+            if (windValue >= oWindValue) {
+                if (operandSwap) {
+                    SkTSwap(oWindValue, oOppValue);
+                }
+                if (flipped) {
+                    windValue -= oWindValue;
+                    oppValue -= oOppValue;
+                } else {
+                    windValue += oWindValue;
+                    oppValue += oOppValue;
+                }
+                if (isXor) {
+                    windValue &= 1;
+                }
+                if (oppXor) {
+                    oppValue &= 1;
+                }
+                oWindValue = oOppValue = 0;
+            } else {
+                if (operandSwap) {
+                    SkTSwap(windValue, oppValue);
+                }
+                if (flipped) {
+                    oWindValue -= windValue;
+                    oOppValue -= oppValue;
+                } else {
+                    oWindValue += windValue;
+                    oOppValue += oppValue;
+                }
+                if (isXor) {
+                    oOppValue &= 1;
+                }
+                if (oppXor) {
+                    oWindValue &= 1;
+                }
+                windValue = oppValue = 0;
+            }
+            start->setWindValue(windValue);
+            start->setOppValue(oppValue);
+            oStart->setWindValue(oWindValue);
+            oStart->setOppValue(oOppValue);
+            if (!windValue && !oppValue) {
+                segment->markDone(start);
+            }
+            if (!oWindValue && !oOppValue) {
+                oSegment->markDone(oStart);
+            }
+            SkOpSpanBase* next = start->next();
+            SkOpSpanBase* oNext = flipped ? oStart->prev() : oStart->next();
+            if (next == end) {
+                break;
+            }
+            start = next->upCast();
+            if (!oNext) {
+                return false;
+            }
+            if (!oNext->upCastable()) {
+                return false;
+            }
+            oStart = oNext->upCast();
+        } while (true);
+    } while ((coin = coin->fNext));
+    return true;
+}
+
+void SkOpCoincidence::detach(SkCoincidentSpans* remove) {
+    SkCoincidentSpans* coin = fHead;
+    SkCoincidentSpans* prev = NULL;
+    SkCoincidentSpans* next;
+    do {
+        next = coin->fNext;
+        if (coin == remove) {
+            if (prev) {
+                prev->fNext = next;
+            } else {
+                fHead = next;
+            }
+            break;
+        }
+        prev = coin;
+    } while ((coin = next));
+    SkASSERT(coin);
+}
+
+void SkOpCoincidence::expand() {
+    SkCoincidentSpans* coin = fHead;
+    if (!coin) {
+        return;
+    }
+    do {
+        SkOpSpan* start = coin->fCoinPtTStart->span()->upCast();
+        SkOpSpanBase* end = coin->fCoinPtTEnd->span();
+        SkOpSegment* segment = coin->fCoinPtTStart->segment();
+        SkOpSegment* oppSegment = coin->fOppPtTStart->segment();
+        SkOpSpan* prev = start->prev();
+        SkOpPtT* oppPtT;
+        if (prev && (oppPtT = prev->contains(oppSegment))) {
+            double midT = (prev->t() + start->t()) / 2;
+            if (segment->isClose(midT, oppSegment)) {
+                coin->fCoinPtTStart = prev->ptT();
+                coin->fOppPtTStart = oppPtT;
+            }
+        }
+        SkOpSpanBase* next = end->final() ? NULL : end->upCast()->next();
+        if (next && (oppPtT = next->contains(oppSegment))) {
+            double midT = (end->t() + next->t()) / 2;
+            if (segment->isClose(midT, oppSegment)) {
+                coin->fCoinPtTEnd = next->ptT();
+                coin->fOppPtTEnd = oppPtT;
+            }
+        }
+    } while ((coin = coin->fNext));
+}
+
+void SkOpCoincidence::fixUp(SkOpPtT* deleted, SkOpPtT* kept) {
+    SkCoincidentSpans* coin = fHead;
+    if (!coin) {
+        return;
+    }
+    do {
+        if (coin->fCoinPtTStart == deleted) {
+            if (coin->fCoinPtTEnd->span() == kept->span()) {
+                return this->detach(coin);
+            }
+            coin->fCoinPtTStart = kept;
+        }
+        if (coin->fCoinPtTEnd == deleted) {
+            if (coin->fCoinPtTStart->span() == kept->span()) {
+                return this->detach(coin);
+            }
+            coin->fCoinPtTEnd = kept;
+        }
+        if (coin->fOppPtTStart == deleted) {
+            if (coin->fOppPtTEnd->span() == kept->span()) {
+                return this->detach(coin);
+            }
+            coin->fOppPtTStart = kept;
+        }
+        if (coin->fOppPtTEnd == deleted) {
+            if (coin->fOppPtTStart->span() == kept->span()) {
+                return this->detach(coin);
+            }
+            coin->fOppPtTEnd = kept;
+        }
+    } while ((coin = coin->fNext));
+}
+
+void SkOpCoincidence::mark() {
+    SkCoincidentSpans* coin = fHead;
+    if (!coin) {
+        return;
+    }
+    do {
+        SkOpSpanBase* end = coin->fCoinPtTEnd->span();
+        SkOpSpanBase* oldEnd = end;
+        SkOpSpan* start = coin->fCoinPtTStart->span()->starter(&end);
+        SkOpSpanBase* oEnd = coin->fOppPtTEnd->span();
+        SkOpSpanBase* oOldEnd = oEnd;
+        SkOpSpanBase* oStart = coin->fOppPtTStart->span()->starter(&oEnd);
+        bool flipped = (end == oldEnd) != (oEnd == oOldEnd);
+        if (flipped) {
+            SkTSwap(oStart, oEnd);
+        }
+        SkOpSpanBase* next = start;
+        SkOpSpanBase* oNext = oStart;
+        // check to see if coincident span could be bigger
+
+        do {
+            next = next->upCast()->next();
+            oNext = flipped ? oNext->prev() : oNext->upCast()->next();
+            if (next == end || oNext == oEnd) {
+                break;
+            }
+            if (!next->containsCoinEnd(oNext)) {
+                next->insertCoinEnd(oNext);
+            }
+            SkOpSpan* nextSpan = next->upCast();
+            SkOpSpan* oNextSpan = oNext->upCast();
+            if (!nextSpan->containsCoincidence(oNextSpan)) {
+                nextSpan->insertCoincidence(oNextSpan);
+            }
+        } while (true);
+    } while ((coin = coin->fNext));
+}
+
+bool SkOpCoincidence::overlap(const SkOpPtT* coin1s, const SkOpPtT* coin1e, 
+        const SkOpPtT* coin2s, const SkOpPtT* coin2e, double* overS, double* overE) const {
+    if (coin1s->segment() != coin2s->segment()) {
+        return false;
+    }
+    *overS = SkTMax(SkTMin(coin1s->fT, coin1e->fT), SkTMin(coin2s->fT, coin2e->fT));
+    *overE = SkTMin(SkTMax(coin1s->fT, coin1e->fT), SkTMax(coin2s->fT, coin2e->fT));
+    return *overS < *overE;
+}