Merge pull request #486 from abarth/painting_context

Refactor PaintingContext

examples/rendering/lib/sector_layout.dart

@@ -282,7 +282,7 @@ class RenderSectorRing extends RenderSectorWithChildren {
     super.paint(context, offset);
     RenderSector child = firstChild;
     while (child != null) {
-      context.paintChild(child, offset.toPoint());
+      context.paintChild(child, offset);
       final SectorChildListParentData childParentData = child.parentData;
       child = childParentData.nextSibling;
     }
@@ -388,7 +388,7 @@ class RenderSectorSlice extends RenderSectorWithChildren {
     RenderSector child = firstChild;
     while (child != null) {
       assert(child.parentData is SectorChildListParentData);
-      context.paintChild(child, offset.toPoint());
+      context.paintChild(child, offset);
       final SectorChildListParentData childParentData = child.parentData;
       child = childParentData.nextSibling;
     }
@@ -470,7 +470,7 @@ class RenderBoxToRenderSectorAdapter extends RenderBox with RenderObjectWithChil
     if (child != null) {
       Rect bounds = offset & size;
       // we move the offset to the center of the circle for the RenderSectors
-      context.paintChild(child, bounds.center);
+      context.paintChild(child, bounds.center.toOffset());
     }
   }
 

packages/flutter/lib/src/material/tabs.dart

@@ -232,7 +232,7 @@ class _RenderTabBar extends RenderBox with
     RenderBox child = firstChild;
     while (child != null) {
       final _TabBarParentData childParentData = child.parentData;
-      context.paintChild(child, childParentData.position + offset);
+      context.paintChild(child, childParentData.offset + offset);
       if (index++ == selectedIndex)
         _paintIndicator(context.canvas, child, offset);
       child = childParentData.nextSibling;

packages/flutter/lib/src/rendering/box.dart

@@ -287,6 +287,8 @@ class BoxHitTestEntry extends HitTestEntry {
 
 /// Parent data used by [RenderBox] and its subclasses
 class BoxParentData extends ParentData {
+  // TODO(abarth): Switch to using an Offset rather than a Point here. This
+  //               value is really the offset from the parent.
   Point _position = Point.origin;
   /// The point at which to paint the child in the parent's coordinate system
   Point get position => _position;
@@ -294,6 +296,7 @@ class BoxParentData extends ParentData {
     assert(RenderObject.debugDoingLayout);
     _position = value;
   }
+  Offset get offset => _position.toOffset();
   String toString() => 'position=$position';
 }
 
@@ -771,7 +774,7 @@ abstract class RenderBoxContainerDefaultsMixin<ChildType extends RenderBox, Pare
     RenderBox child = firstChild;
     while (child != null) {
       final ParentDataType childParentData = child.parentData;
-      context.paintChild(child, childParentData.position + offset);
+      context.paintChild(child, childParentData.offset + offset);
       child = childParentData.nextSibling;
     }
   }

packages/flutter/lib/src/rendering/overflow.dart

@@ -131,7 +131,7 @@ class RenderOverflowBox extends RenderBox with RenderObjectWithChildMixin<Render
 
   void paint(PaintingContext context, Offset offset) {
     if (child != null)
-      context.paintChild(child, offset.toPoint());
+      context.paintChild(child, offset);
   }
 
   void debugDescribeSettings(List<String> settings) {
@@ -198,7 +198,7 @@ class RenderSizedOverflowBox extends RenderBox with RenderObjectWithChildMixin<R
 
   void paint(PaintingContext context, Offset offset) {
     if (child != null)
-      context.paintChild(child, offset.toPoint());
+      context.paintChild(child, offset);
   }
 }
 

packages/flutter/lib/src/rendering/proxy_box.dart

@@ -77,7 +77,7 @@ class RenderProxyBox extends RenderBox with RenderObjectWithChildMixin<RenderBox
 
   void paint(PaintingContext context, Offset offset) {
     if (child != null)
-      context.paintChild(child, offset.toPoint());
+      context.paintChild(child, offset);
   }
 }
 
@@ -501,10 +501,12 @@ class RenderOpacity extends RenderProxyBox {
       int a = _alpha;
       if (a == 0)
         return;
-      if (a == 255)
-        context.paintChild(child, offset.toPoint());
-      else
-        context.paintChildWithOpacity(child, offset.toPoint(), null, a);
+      if (a == 255) {
+        context.paintChild(child, offset);
+        return;
+      }
+      // TODO(abarth): We should pass bounds here.
+      context.pushOpacity(needsCompositing, offset, null, a, super.paint);
     }
   }
 
@@ -540,7 +542,7 @@ class RenderShaderMask extends RenderProxyBox {
 
   void paint(PaintingContext context, Offset offset) {
     if (child != null)
-      context.paintChildWithShaderMask(child, offset.toPoint(), offset & size, _shaderCallback, _transferMode);
+      context.pushShaderMask(needsCompositing, offset, Point.origin & size, _shaderCallback, _transferMode, super.paint);
   }
 }
 
@@ -552,7 +554,7 @@ class RenderClipRect extends RenderProxyBox {
 
   void paint(PaintingContext context, Offset offset) {
     if (child != null)
-      context.paintChildWithClipRect(child, offset.toPoint(), offset & size);
+      context.pushClipRect(needsCompositing, offset, Point.origin & size, super.paint);
   }
 }
 
@@ -598,9 +600,9 @@ class RenderClipRRect extends RenderProxyBox {
 
   void paint(PaintingContext context, Offset offset) {
     if (child != null) {
-      Rect rect = offset & size;
+      Rect rect = Point.origin & size;
       ui.RRect rrect = new ui.RRect.fromRectXY(rect, xRadius, yRadius);
-      context.paintChildWithClipRRect(child, offset.toPoint(), rect, rrect);
+      context.pushClipRRect(needsCompositing, offset, rect, rrect, super.paint);
     }
   }
 }
@@ -615,7 +617,7 @@ class RenderClipOval extends RenderProxyBox {
   Rect _cachedRect;
   Path _cachedPath;
 
-  Path _getPath(Rect rect) {
+  Path _getClipPath(Rect rect) {
     if (rect != _cachedRect) {
       _cachedRect = rect;
       _cachedPath = new Path()..addOval(_cachedRect);
@@ -634,8 +636,8 @@ class RenderClipOval extends RenderProxyBox {
 
   void paint(PaintingContext context, Offset offset) {
     if (child != null) {
-      Rect rect = offset & size;
-      context.paintChildWithClipPath(child, offset.toPoint(), rect, _getPath(rect));
+      Rect bounds = Point.origin & size;
+      context.pushClipPath(needsCompositing, offset, bounds, _getClipPath(bounds), super.paint);
     }
   }
 }
@@ -863,7 +865,7 @@ class RenderTransform extends RenderProxyBox {
 
   void paint(PaintingContext context, Offset offset) {
     if (child != null)
-      context.paintChildWithTransform(child, offset.toPoint(), _effectiveTransform);
+      context.pushTransform(needsCompositing, offset, _effectiveTransform, super.paint);
   }
 
   void applyPaintTransform(Matrix4 transform) {

packages/flutter/lib/src/rendering/shifted_box.dart

@@ -56,7 +56,7 @@ abstract class RenderShiftedBox extends RenderBox with RenderObjectWithChildMixi
   void paint(PaintingContext context, Offset offset) {
     if (child != null) {
       final BoxParentData childParentData = child.parentData;
-      context.paintChild(child, childParentData.position + offset);
+      context.paintChild(child, childParentData.offset + offset);
     }
   }
 

packages/flutter/lib/src/rendering/stack.dart

@@ -489,6 +489,6 @@ class RenderIndexedStack extends RenderStackBase {
       return;
     RenderBox child = _childAtIndex();
     final StackParentData childParentData = child.parentData;
-    context.paintChild(child, childParentData.position + offset);
+    context.paintChild(child, childParentData.offset + offset);
   }
 }

packages/flutter/lib/src/rendering/statistics_box.dart

@@ -54,6 +54,6 @@ class RenderStatisticsBox extends RenderBox {
   }
 
   void paint(PaintingContext context, Offset offset) {
-    context.paintStatistics(optionsMask, rasterizerThreshold, offset, size);
+    context.pushStatistics(offset, optionsMask, rasterizerThreshold, size);
   }
 }

packages/flutter/lib/src/rendering/view.dart

@@ -110,7 +110,7 @@ class RenderView extends RenderObject with RenderObjectWithChildMixin<RenderBox>
 
   void paint(PaintingContext context, Offset offset) {
     if (child != null)
-      context.paintChild(child, offset.toPoint());
+      context.paintChild(child, offset);
   }
 
   /// Uploads the composited layer tree to the engine

packages/flutter/lib/src/rendering/viewport.dart

@@ -146,12 +146,15 @@ class RenderViewport extends RenderBox with RenderObjectWithChildMixin<RenderBox
   void paint(PaintingContext context, Offset offset) {
     if (child != null) {
       Offset roundedScrollOffset = _scrollOffsetRoundedToIntegerDevicePixels;
-      bool _needsClip = offset < Offset.zero ||
-                        !(offset & size).contains(((offset - roundedScrollOffset) & child.size).bottomRight);
-      if (_needsClip)
-        context.paintChildWithClipRect(child, (offset - roundedScrollOffset).toPoint(), offset & size);
-      else
-        context.paintChild(child, (offset - roundedScrollOffset).toPoint());
+      bool _needsClip = offset < Offset.zero
+          || !(offset & size).contains(((offset - roundedScrollOffset) & child.size).bottomRight);
+      if (_needsClip) {
+        context.pushClipRect(needsCompositing, offset, Point.origin & size, (PaintingContext context, Offset offset) {
+          context.paintChild(child, offset - roundedScrollOffset);
+        });
+      } else {
+        context.paintChild(child, offset - roundedScrollOffset);
+      }
     }
   }