Implement ClipRRect

sky/sdk/lib/rendering/box.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import 'dart:math' as math;
 import 'dart:sky' as sky;
 
 import 'package:vector_math/vector_math.dart';
 
 import '../base/debug.dart';
@@ skipping 538 matching lines @@
   void paint(RenderCanvas canvas) {
     if (child != null) {
       canvas.save();
       canvas.clipRect(new Rect.fromSize(size));
       child.paint(canvas);
       canvas.restore();
     }
   }
 }
 
+class RenderClipRRect extends RenderProxyBox {
+  final double xRad;
+  final double yRad;

[abarth-chromium, 2015/06/25 17:11:21]

xRadius and yRadius

Please use complete words in variable names.

Also, these shouldn't be final.  They should have setters that compare the new
value to the existing value and call markNeedsPaint if the value changes.

[Hixie, 2015/06/25 17:16:58]

also, constructors first. fields second or with the code that uses them.

+  RenderClipRRect({ RenderBox child, this.xRad, this.yRad }) : super(child) {
+    assert(xRad != null);
+    assert(yRad != null);
+  }
+
+  void paint(RenderCanvas canvas) {
+    if (child != null) {
+      Rect rect = new Rect.fromSize(size);
+      canvas.saveLayer(rect, new Paint());
+      sky.RRect rrect = new sky.RRect()..setRectXY(rect, xRad, yRad);

[Hixie, 2015/06/25 17:16:59]

Doesn't RRect() have a suitable constructor?

Indeed, why isn't RRect immutable?

+      canvas.clipRRect(rrect);

[Hixie, 2015/06/25 17:16:59]

What's the anti-aliasing story here?

(ok, trick question, we talked about this. But we should contact Skia people
about it.)

+      child.paint(canvas);
+      canvas.restore();
+    }
+  }
+}
+
 class RenderClipOval extends RenderProxyBox {
   RenderClipOval({ RenderBox child }) : super(child);
 
   void paint(RenderCanvas canvas) {
     if (child != null) {
       Rect rect = new Rect.fromSize(size);
       canvas.saveLayer(rect, new Paint());
       Path path = new Path();
       path.addOval(rect);
       canvas.clipPath(path);
@@ skipping 537 matching lines @@
 
   void defaultPaint(RenderCanvas canvas) {
     RenderBox child = firstChild;
     while (child != null) {
       assert(child.parentData is ParentDataType);
       canvas.paintChild(child, child.parentData.position);
       child = child.parentData.nextSibling;
     }
   }
 }