path ops -- fix skp bugs

src/pathops/SkPathOpsSimplify.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "SkAddIntersections.h"
 #include "SkOpEdgeBuilder.h"
 #include "SkPathOpsCommon.h"
 #include "SkPathWriter.h"
@@ skipping 14 matching lines @@
                 SkASSERT(topLeft.fX != SK_ScalarMin && topLeft.fY != SK_ScalarMin);
                 topLeft.fX = topLeft.fY = SK_ScalarMin;
                 continue;
             }
             break;
         }
         SkTDArray<SkOpSpan*> chaseArray;
         do {
             if (current->activeWinding(index, endIndex)) {
                 do {
+                    if (!unsortable && current->done()) {
             #if DEBUG_ACTIVE_SPANS
-                    if (!unsortable && current->done()) {
                         DebugShowActiveSpans(contourList);
+            #endif
+                        if (simple->isEmpty()) {
+                            simple->init();
+                            break;
+                        }
                     }
-            #endif
                     SkASSERT(unsortable || !current->done());
                     int nextStart = index;
                     int nextEnd = endIndex;
                     SkOpSegment* next = current->findNextWinding(&chaseArray, &nextStart, &nextEnd,
                             &unsortable);
                     if (!next) {
                         if (!unsortable && simple->hasMove()
                                 && current->verb() != SkPath::kLine_Verb
                                 && !simple->isClosed()) {
                             current->addCurveTo(index, endIndex, simple, true);
                             SkASSERT(simple->isClosed());
                         }
                         break;
                     }
         #if DEBUG_FLOW
             SkDebugf("%s current id=%d from=(%1.9g,%1.9g) to=(%1.9g,%1.9g)\n", __FUNCTION__,
                     current->debugID(), current->xyAtT(index).fX, current->xyAtT(index).fY,
                     current->xyAtT(endIndex).fX, current->xyAtT(endIndex).fY);
         #endif
                     current->addCurveTo(index, endIndex, simple, true);
                     current = next;
                     index = nextStart;
                     endIndex = nextEnd;
                 } while (!simple->isClosed() && (!unsortable
                         || !current->done(SkMin32(index, endIndex))));
                 if (current->activeWinding(index, endIndex) && !simple->isClosed()) {
-                    SkASSERT(unsortable);
+                    SkASSERT(unsortable || simple->isEmpty());
                     int min = SkMin32(index, endIndex);
                     if (!current->done(min)) {
                         current->addCurveTo(index, endIndex, simple, true);
                         current->markDoneUnary(min);
                     }
                 }
                 simple->close();
             } else {
                 SkOpSpan* last = current->markAndChaseDoneUnary(index, endIndex);
                 if (last && !last->fLoop) {
@@ skipping 98 matching lines @@
         }
         SkOpContour* next;
         do {
             next = *nextPtr++;
         } while (AddIntersectTs(current, next) && nextPtr != listEnd);
     } while (currentPtr != listEnd);
     // eat through coincident edges
     CoincidenceCheck(&contourList, 0);
     FixOtherTIndex(&contourList);
     SortSegments(&contourList);
-#if DEBUG_ACTIVE_SPANS
+#if DEBUG_ACTIVE_SPANS || DEBUG_ACTIVE_SPANS_FIRST_ONLY
     DebugShowActiveSpans(contourList);
 #endif
     // construct closed contours
     SkPathWriter simple(*result);
     if (builder.xorMask() == kWinding_PathOpsMask ? bridgeWinding(contourList, &simple)
                 : !bridgeXor(contourList, &simple))
     {  // if some edges could not be resolved, assemble remaining fragments
         SkPath temp;
         temp.setFillType(fillType);
         SkPathWriter assembled(temp);
         Assemble(simple, &assembled);
         *result = *assembled.nativePath();
         result->setFillType(fillType);
     }
     return true;
 }