Fix for degenerate stroke rect

src/gpu/batches/GrRectBatchFactory.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrRectBatchFactory.h"
 
 #include "GrAAStrokeRectBatch.h"
@@ skipping 15 matching lines @@
         devStrokeSize.setAbs(devStrokeSize);
     } else {
         devStrokeSize.set(SK_Scalar1, SK_Scalar1);
     }
 
     const SkScalar dx = devStrokeSize.fX;
     const SkScalar dy = devStrokeSize.fY;
     const SkScalar rx = SkScalarMul(dx, SK_ScalarHalf);
     const SkScalar ry = SkScalarMul(dy, SK_ScalarHalf);
 
-    SkScalar spare;
-    {
-        SkScalar w = devRect.width() - dx;
-        SkScalar h = devRect.height() - dy;
-        spare = SkTMin(w, h);
-    }
-
     SkRect devOutside(devRect);
     devOutside.outset(rx, ry);
 
     bool miterStroke = true;
     // For hairlines, make bevel and round joins appear the same as mitered ones.
     // small miter limit means right angles show bevel...
     if ((width > 0) && (stroke.getJoin() != SkPaint::kMiter_Join ||
                         stroke.getMiter() < SK_ScalarSqrt2)) {
         miterStroke = false;
     }
 
-    if (spare <= 0 && miterStroke) {
-        return CreateAAFill(color, viewMatrix, devOutside, devOutside);
-    }
-
     SkRect devInside(devRect);
     devInside.inset(rx, ry);
 
+    // If we have a degenerate stroking rect(ie the stroke is larger than inner rect) then we
+    // make a degenerate inside rect to avoid double hitting.  We will also jam all of the points
+    // together when we render these rects.
+    SkScalar spare;
+    {
+        SkScalar w = devRect.width() - dx;
+        SkScalar h = devRect.height() - dy;
+        spare = SkTMin(w, h);
+    }
+
+    bool degenerate = spare <= 0;
+    if (degenerate) {

[robertphillips, 2015/09/21 17:12:44]

Just use devRect.centerX() ?

[joshualitt, 2015/09/21 19:51:25]

Acknowledged.

+        SkScalar midPoint = devRect.width() / 2.0f + devRect.fLeft;
+        devInside.fLeft = devInside.fRight = midPoint;
+

[robertphillips, 2015/09/21 17:12:44]

Just use devRect.centerY() ?

[joshualitt, 2015/09/21 19:51:25]

Acknowledged.

+        midPoint = devRect.height() / 2.0f + devRect.fTop;
+        devInside.fTop = devInside.fBottom = midPoint;
+    }
+
     SkRect devOutsideAssist(devRect);
 
     // For bevel-stroke, use 2 SkRect instances(devOutside and devOutsideAssist)
     // to draw the outer of the rect. Because there are 8 vertices on the outer
     // edge, while vertex number of inner edge is 4, the same as miter-stroke.
     if (!miterStroke) {
         devOutside.inset(0, ry);
         devOutsideAssist.outset(0, ry);
     }
 
     return GrAAStrokeRectBatch::Create(color, viewMatrix, devOutside, devOutsideAssist, devInside,
-                                       miterStroke);
+                                       miterStroke, degenerate);
 }
 
 GrDrawBatch* CreateAAFillNestedRects(GrColor color,
                                      const SkMatrix& viewMatrix,
                                      const SkRect rects[2]) {
     SkASSERT(viewMatrix.rectStaysRect());
     SkASSERT(!rects[0].isEmpty() && !rects[1].isEmpty());
 
     SkRect devOutside, devInside;
     viewMatrix.mapRect(&devOutside, rects[0]);
     viewMatrix.mapRect(&devInside, rects[1]);
 

[robertphillips, 2015/09/21 17:12:44]

Don't we want to get rid of this and pass 'true' to Create ?

[joshualitt, 2015/09/21 19:51:25]

Acknowledged.

     if (devInside.isEmpty()) {
         return CreateAAFill(color, viewMatrix, devOutside, devOutside);
     }
 
-    return GrAAStrokeRectBatch::Create(color, viewMatrix, devOutside, devOutside, devInside, true);
+    return GrAAStrokeRectBatch::Create(color, viewMatrix, devOutside, devOutside, devInside, true,
+                                       false);
 }
 
 };