nc seal breaks simplify

This test has nearly coincident lines that are missorted.
The underlying bug is caused when a pair of curves
are coincident when reduced to line segments, but the
end points aren't detected.

The error was generated by running nanobench over all svg
sample data with the distance field patch installed.

TBR=reed@google.com
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2440043003

Review-Url: https://codereview.chromium.org/2440043003

1 files changed, 23 insertions, 5 deletions

diff --git a/src/pathops/SkPathOpsTSect.h b/src/pathops/SkPathOpsTSect.h
index 51ea44a26c..fbfb8c138f 100644
--- a/src/pathops/SkPathOpsTSect.h
+++ b/src/pathops/SkPathOpsTSect.h
@@ -315,6 +315,12 @@ private:
     bool removeSpan(SkTSpan<TCurve, OppCurve>* span);
     void removeSpanRange(SkTSpan<TCurve, OppCurve>* first, SkTSpan<TCurve, OppCurve>* last);
     void removeSpans(SkTSpan<TCurve, OppCurve>* span, SkTSect<OppCurve, TCurve>* opp);
+    void removedEndCheck(SkTSpan<TCurve, OppCurve>* span);
+
+    void resetRemovedEnds() { 
+        fRemovedStartT = fRemovedEndT = false;
+    }
+
     SkTSpan<TCurve, OppCurve>* spanAtT(double t, SkTSpan<TCurve, OppCurve>** priorSpan);
     SkTSpan<TCurve, OppCurve>* tail();
     bool trim(SkTSpan<TCurve, OppCurve>* span, SkTSect<OppCurve, TCurve>* opp);
@@ -865,7 +871,8 @@ SkTSect<TCurve, OppCurve>::SkTSect(const TCurve& c
     PATH_OPS_DEBUG_T_SECT_PARAMS(fDebugCount(0))
     PATH_OPS_DEBUG_T_SECT_PARAMS(fDebugAllocatedCount(0))
 {
-    fHead = addOne();
+    this->resetRemovedEnds();
+    fHead = this->addOne();
     SkDEBUGCODE(fHead->debugSetGlobalState(debugGlobalState));
     fHead->init(c);
 }
@@ -1360,7 +1367,9 @@ int SkTSect<TCurve, OppCurve>::intersects(SkTSpan<TCurve, OppCurve>* span,
         if (!sects) {
             return -1;
         }
+        this->removedEndCheck(span);
         span->fStartT = span->fEndT = i[0][0];
+        opp->removedEndCheck(oppSpan);
         oppSpan->fStartT = oppSpan->fEndT = i[1][0];
         return *oppResult = 2;
     }
@@ -1735,13 +1744,18 @@ void SkTSect<TCurve, OppCurve>::removeCoincident(SkTSpan<TCurve, OppCurve>* span
 }
 
 template<typename TCurve, typename OppCurve>
-bool SkTSect<TCurve, OppCurve>::removeSpan(SkTSpan<TCurve, OppCurve>* span) {
+void SkTSect<TCurve, OppCurve>::removedEndCheck(SkTSpan<TCurve, OppCurve>* span) {
     if (!span->fStartT) {
         fRemovedStartT = true;
     }
     if (1 == span->fEndT) {
         fRemovedEndT = true;
     }
+}
+
+template<typename TCurve, typename OppCurve>
+bool SkTSect<TCurve, OppCurve>::removeSpan(SkTSpan<TCurve, OppCurve>* span) {\
+    this->removedEndCheck(span);
     this->unlinkSpan(span);
     return this->markSpanGone(span);
 }
@@ -2141,14 +2155,14 @@ void SkTSect<TCurve, OppCurve>::BinarySearch(SkTSect<TCurve, OppCurve>* sect1,
             break;
         }
         SkTSpan<OppCurve, TCurve>* largest2 = sect2->boundsMax();
-        sect1->fRemovedStartT = sect1->fRemovedEndT = false;
-        sect2->fRemovedStartT = sect2->fRemovedEndT = false;
         // split it
         if (!largest2 || (largest1 && (largest1->fBoundsMax > largest2->fBoundsMax
                 || (!largest1->fCollapsed && largest2->fCollapsed)))) {
             if (largest1->fCollapsed) {
                 break;
             }
+            sect1->resetRemovedEnds();
+            sect2->resetRemovedEnds();
             // trim parts that don't intersect the opposite
             SkTSpan<TCurve, OppCurve>* half1 = sect1->addOne();
             SkDEBUGCODE(half1->debugSetGlobalState(sect1->globalState()));
@@ -2167,6 +2181,8 @@ void SkTSect<TCurve, OppCurve>::BinarySearch(SkTSect<TCurve, OppCurve>* sect1,
             if (largest2->fCollapsed) {
                 break;
             }
+            sect1->resetRemovedEnds();
+            sect2->resetRemovedEnds();
             // trim parts that don't intersect the opposite
             SkTSpan<OppCurve, TCurve>* half2 = sect2->addOne();
             SkDEBUGCODE(half2->debugSetGlobalState(sect2->globalState()));
@@ -2262,7 +2278,7 @@ void SkTSect<TCurve, OppCurve>::BinarySearch(SkTSect<TCurve, OppCurve>* sect1,
         } while ((coincident = coincident->fNext));
     }
     int zeroOneSet = EndsEqual(sect1, sect2, intersections);
-    if (!sect1->fHead || !sect2->fHead) {
+//    if (!sect1->fHead || !sect2->fHead) {
         // if the final iteration contains an end (0 or 1),
         if (sect1->fRemovedStartT && !(zeroOneSet & kZeroS1Set)) {
             SkTCoincident<TCurve, OppCurve> perp;   // intersect perpendicular with opposite curve
@@ -2292,6 +2308,8 @@ void SkTSect<TCurve, OppCurve>::BinarySearch(SkTSect<TCurve, OppCurve>* sect1,
                 intersections->insert(perp.perpT(), 1, perp.perpPt());
             }
         }
+//    }
+    if (!sect1->fHead || !sect2->fHead) {
         return;
     }
     sect1->recoverCollapsed();