commit ab2d73b06fe6c518be1d399a79c9cc39db21abb6
author Cary Clark <caryclark@google.com> Fri Dec 16 17:17:25 2016 -0500
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Fri Dec 16 22:47:00 2016 +0000
tree b0a7c6a51acbaeb6aaca55361a838daabd506003
parent ee1c73fc1b8a616ac79572759b02435698171fbf

rework xor to be more like winding

Pathops is very well exercised with winding paths,
but less so with xor (even odd) paths.

Rewrite the xor main loop to look like the winding
one to take advantage of the latter's bug fixes.

TBR=reed@google.com
BUG=skia:6041

Change-Id: Ied8d522254a327b1817b54f0abbf4414f5fab7da
Reviewed-on: https://skia-review.googlesource.com/6228
Reviewed-by: Cary Clark <caryclark@google.com>
Commit-Queue: Cary Clark <caryclark@google.com>

src/pathops/SkPathOpsSimplify.cpp

diff --git a/src/pathops/SkPathOpsSimplify.cpp b/src/pathops/SkPathOpsSimplify.cpp
index 8cd770d..eb71e73 100644
--- a/src/pathops/SkPathOpsSimplify.cpp
+++ b/src/pathops/SkPathOpsSimplify.cpp
@@ -84,30 +84,25 @@
 
 // returns true if all edges were processed
 static bool bridgeXor(SkOpContourHead* contourList, SkPathWriter* simple) {
-    SkOpSegment* current;
-    SkOpSpanBase* start;
-    SkOpSpanBase* end;
     bool unsortable = false;
-    while ((current = FindUndone(contourList, &start, &end))) {
+    do {
+        SkOpSpan* span = FindUndone(contourList);
+        if (!span) {
+            break;
+        }
+        SkOpSegment* current = span->segment();
+        SkOpSpanBase* start = span->next();
+        SkOpSpanBase* end = span;
         do {
             if (!unsortable && current->done()) {
-                SkPathOpsDebug::ShowActiveSpans(contourList);
+                break;
             }
             SkASSERT(unsortable || !current->done());
             SkOpSpanBase* nextStart = start;
             SkOpSpanBase* nextEnd = end;
-            SkOpSegment* next = current->findNextXor(&nextStart, &nextEnd, &unsortable);
+            SkOpSegment* next = current->findNextXor(&nextStart, &nextEnd,
+                    &unsortable);
             if (!next) {
-                if (!unsortable && simple->hasMove()
-                        && current->verb() != SkPath::kLine_Verb
-                        && !simple->isClosed()) {
-                    if (!current->addCurveTo(start, end, simple)) {
-                        return false;
-                    }
-                    if (!simple->isClosed()) {
-                        SkPathOpsDebug::ShowActiveSpans(contourList);
-                    }
-                }
                 break;
             }
         #if DEBUG_FLOW
@@ -123,7 +118,6 @@
             end = nextEnd;
         } while (!simple->isClosed() && (!unsortable || !start->starter(end)->done()));
         if (!simple->isClosed()) {
-            SkASSERT(unsortable);
             SkOpSpan* spanStart = start->starter(end);
             if (!spanStart->done()) {
                 if (!current->addCurveTo(start, end, simple)) {
@@ -134,7 +128,7 @@
         }
         simple->finishContour();
         SkPathOpsDebug::ShowActiveSpans(contourList);
-    }
+    } while (true);
     return true;
 }