fix bugs found by computing flat clips in 800K skps

tests/PathOpsExtendedTest.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 "PathOpsExtendedTest.h"
 #include "PathOpsThreadedCommon.h"
 #include "SkBitmap.h"
@@ skipping 138 matching lines @@
 static void showPathData(const SkPath& path) {
     SkPath::RawIter iter(path);
     uint8_t verb;
     SkPoint pts[4];
     SkPoint firstPt = {0, 0}, lastPt = {0, 0};
     bool firstPtSet = false;
     bool lastPtSet = true;
     while ((verb = iter.next(pts)) != SkPath::kDone_Verb) {
         switch (verb) {
             case SkPath::kMove_Verb:
+                if (firstPtSet && lastPtSet && firstPt != lastPt) {
+                    SkDebugf("{{%1.9g,%1.9g}, {%1.9g,%1.9g}},\n", lastPt.fX, lastPt.fY,
+                            firstPt.fX, firstPt.fY);
+                    lastPtSet = false;
+                }
                 firstPt = pts[0];
                 firstPtSet = true;
                 continue;
             case SkPath::kLine_Verb:
                 SkDebugf("{{%1.9g,%1.9g}, {%1.9g,%1.9g}},\n", pts[0].fX, pts[0].fY,
                         pts[1].fX, pts[1].fY);
                 lastPt = pts[1];
                 lastPtSet = true;
                 break;
             case SkPath::kQuad_Verb:
@@ skipping 14 matching lines @@
                     SkDebugf("{{%1.9g,%1.9g}, {%1.9g,%1.9g}},\n", lastPt.fX, lastPt.fY,
                             firstPt.fX, firstPt.fY);
                 }
                 firstPtSet = lastPtSet = false;
                 break;
             default:
                 SkDEBUGFAIL("bad verb");
                 return;
         }
     }
+    if (firstPtSet && lastPtSet && firstPt != lastPt) {
+        SkDebugf("{{%1.9g,%1.9g}, {%1.9g,%1.9g}},\n", lastPt.fX, lastPt.fY,
+                firstPt.fX, firstPt.fY);
+    }
 }
 #endif
 
 void showOp(const SkPathOp op) {
     switch (op) {
         case kDifference_PathOp:
             SkDebugf("op difference\n");
             break;
         case kIntersect_PathOp:
             SkDebugf("op intersect\n");
@@ skipping 200 matching lines @@
         const SkPathOp shapeOp, const SkMatrix& scale) {
     SkASSERT((unsigned) shapeOp < SK_ARRAY_COUNT(opStrs));
     SkString defaultTestName;
     if (!testName) {
         defaultTestName.printf("xOp%d%s", gTestNo, opSuffixes[shapeOp]);
         testName = defaultTestName.c_str();
     }
     SkDebugf("static void %s(skiatest::Reporter* reporter, const char* filename) {\n", testName);
     *gTestOp.append() = shapeOp;
     ++gTestNo;
-    SkDebugf("\n*** this test fails ***\n");
     SkDebugf("    SkPath path, pathB;\n");
     showPath(a, "path", false);
     showPath(b, "pathB", false);
     SkDebugf("    testPathOp(reporter, path, pathB, %s, filename);\n", opStrs[shapeOp]);
     SkDebugf("}\n");
     drawAsciiPaths(scaledOne, scaledTwo, true);
 }
 
 void ShowTestArray() {
     for (int x = gTestFirst; x < gTestNo; ++x) {
         SkDebugf("    TEST(xOp%d%s),\n", x, opSuffixes[gTestOp[x - gTestFirst]]);
     }
 }
 
 static int comparePaths(skiatest::Reporter* reporter, const char* testName, const SkPath& one,
         const SkPath& scaledOne, const SkPath& two, const SkPath& scaledTwo, SkBitmap& bitmap,
         const SkPath& a, const SkPath& b, const SkPathOp shapeOp, const SkMatrix& scale) {
     int errors2x2;
     (void) pathsDrawTheSame(bitmap, scaledOne, scaledTwo, errors2x2);
     if (errors2x2 == 0) {
         if (gShowPath) {
             showPathOpPath(testName, one, two, a, b, scaledOne, scaledTwo, shapeOp, scale);
         }
         return 0;
     }
     const int MAX_ERRORS = 8;
     if (errors2x2 > MAX_ERRORS && gComparePathsAssert) {
         SK_DECLARE_STATIC_MUTEX(compareDebugOut3);
         SkAutoMutexAcquire autoM(compareDebugOut3);
+        SkDebugf("\n*** this test fails ***\n");
         showPathOpPath(testName, one, two, a, b, scaledOne, scaledTwo, shapeOp, scale);
         REPORTER_ASSERT(reporter, 0);
     } else if (gShowPath || errors2x2 == MAX_ERRORS || errors2x2 == MAX_ERRORS - 1) {
         SK_DECLARE_STATIC_MUTEX(compareDebugOut4);
         SkAutoMutexAcquire autoM(compareDebugOut4);
         showPathOpPath(testName, one, two, a, b, scaledOne, scaledTwo, shapeOp, scale);
     }
     return errors2x2 > MAX_ERRORS ? errors2x2 : 0;
 }
 
@@ skipping 287 matching lines @@
         if (tests[index].fun == stopTest) {
             SkDebugf("lastTest\n");
             break;
         }
         if (index == last) {
             break;
         }
         index += reverse ? -1 : 1;
     } while (true);
 }