path ops -- rewrite angle sort

This is a major change resulting from a minor
tweak. In the old code, the intersection point
of two curves was shared between them, but the
intersection points and end points of sorted edges was
computed directly from the intersection T value.

In this CL, both intersection points and sorted points
are the same, and intermediate control points are computed
to preserve their slope.

The sort itself has been completely rewritten to be more
robust and remove 'magic' checks, conditions that empirically
worked but couldn't be rationalized.

This CL was triggered by errors generated computing the clips
of SKP files. At this point, all 73M standard tests work and
at least the first troublesome SKPs work.

Review URL: https://codereview.chromium.org/15338003

git-svn-id: http://skia.googlecode.com/svn/trunk@9432 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 6 insertions, 0 deletions

diff --git a/src/pathops/SkPathOpsQuad.h b/src/pathops/SkPathOpsQuad.h
index d5ca0c7443..d06f3449bf 100644
--- a/src/pathops/SkPathOpsQuad.h
+++ b/src/pathops/SkPathOpsQuad.h
@@ -19,6 +19,11 @@ struct SkDQuadPair {
 struct SkDQuad {
     SkDPoint fPts[3];
 
+    SkDQuad flip() const {
+        SkDQuad result = {{fPts[2], fPts[1], fPts[0]}};
+        return result;
+    }
+
     void set(const SkPoint pts[3]) {
         fPts[0] = pts[0];
         fPts[1] = pts[1];
@@ -29,6 +34,7 @@ struct SkDQuad {
     SkDPoint& operator[](int n) { SkASSERT(n >= 0 && n < 3); return fPts[n]; }
 
     static int AddValidTs(double s[], int realRoots, double* t);
+    void align(int endIndex, SkDPoint* dstPt) const;
     SkDQuadPair chopAt(double t) const;
     SkDVector dxdyAtT(double t) const;
     static int FindExtrema(double a, double b, double c, double tValue[1]);