commit 0c888286f7db7e9cd861b2e425a17e109601d3fa
author commit-bot@chromium.org <commit-bot@chromium.org@2bbb7eff-a529-9590-31e7-b0007b416f81> Fri Apr 19 19:01:45 2013 +0000
committer commit-bot@chromium.org <commit-bot@chromium.org@2bbb7eff-a529-9590-31e7-b0007b416f81> Fri Apr 19 19:01:45 2013 +0000
tree a7e4259c2236ba4fff836716eead4c738917ff33
parent 68567790c6d3b77e030d667e856fc20b3b945fe7

Fix non-uniform scale and stroked ellipses

Strokes were not being scaled properly for ellipses -- the 
view matrix was being reset before the scale factors were 
being applied. Scaling the stroke has been moved up higher in 
the process. Also applies some optimizations suggested by 
robertphillips.

R=robertphillips@google.com

Author: jvanverth@google.com

Review URL: https://chromiumcodereview.appspot.com/14017012

git-svn-id: http://skia.googlecode.com/svn/trunk@8777 2bbb7eff-a529-9590-31e7-b0007b416f81

src/gpu/GrOvalRenderer.cpp

diff --git a/src/gpu/GrOvalRenderer.cpp b/src/gpu/GrOvalRenderer.cpp
index 42fb2b7..3ecd302 100644
--- a/src/gpu/GrOvalRenderer.cpp
+++ b/src/gpu/GrOvalRenderer.cpp
@@ -420,17 +420,26 @@
     }
 #endif
 
+    // do any matrix crunching before we reset the draw state for device coords
     const SkMatrix& vm = drawState->getViewMatrix();
     GrPoint center = GrPoint::Make(ellipse.centerX(), ellipse.centerY());
     vm.mapPoints(&center, 1);
-    SkRect xformedRect;
-    vm.mapRect(&xformedRect, ellipse);
-    SkScalar xRadius = SkScalarHalf(xformedRect.width());
-    SkScalar yRadius = SkScalarHalf(xformedRect.height());
+    SkScalar ellipseXRadius = SkScalarHalf(ellipse.width());
+    SkScalar ellipseYRadius = SkScalarHalf(ellipse.height());
+    SkScalar xRadius = SkScalarAbs(vm[SkMatrix::kMScaleX]*ellipseXRadius + 
+                                   vm[SkMatrix::kMSkewY]*ellipseYRadius);
+    SkScalar yRadius = SkScalarAbs(vm[SkMatrix::kMSkewX]*ellipseXRadius + 
+                                   vm[SkMatrix::kMScaleY]*ellipseYRadius);
     if (SkScalarDiv(xRadius, yRadius) > 2 || SkScalarDiv(yRadius, xRadius) > 2) {
         return false;
     }
 
+    // do (potentially) anisotropic mapping of stroke
+    SkVector scaledStroke;
+    SkScalar strokeWidth = stroke.getWidth();
+    scaledStroke.fX = SkScalarAbs(strokeWidth*(vm[SkMatrix::kMScaleX] + vm[SkMatrix::kMSkewY]));
+    scaledStroke.fY = SkScalarAbs(strokeWidth*(vm[SkMatrix::kMSkewX] + vm[SkMatrix::kMScaleY]));
+
     GrDrawState::AutoDeviceCoordDraw adcd(drawState);
     if (!adcd.succeeded()) {
         return false;
@@ -472,12 +481,7 @@
     SkScalar innerRatio = 1.0f;
 
     if (SkStrokeRec::kFill_Style != style) {
-        SkScalar strokeWidth = stroke.getWidth();
 
-        // do (potentially) anisotropic mapping
-        SkVector scaledStroke;
-        scaledStroke.set(strokeWidth, strokeWidth);
-        vm.mapVectors(&scaledStroke, 1);
 
         if (SkScalarNearlyZero(scaledStroke.length())) {
             scaledStroke.set(SK_ScalarHalf, SK_ScalarHalf);