Do not copy paths, rects, and rrects when layer offset is zero (flutter#34587)

yjbanov · web-flow · commit b15b5b90a0c5 · 2019-06-19T12:32:12.000-07:00
diff --git a/packages/flutter/lib/src/rendering/layer.dart b/packages/flutter/lib/src/rendering/layer.dart
@@ -330,7 +330,7 @@ class TextureLayer extends Layer {
 
   @override
   ui.EngineLayer addToScene(ui.SceneBuilder builder, [ Offset layerOffset = Offset.zero ]) {
-    final Rect shiftedRect = rect.shift(layerOffset);
+    final Rect shiftedRect = layerOffset == Offset.zero ? rect : rect.shift(layerOffset);
     builder.addTexture(
       textureId,
       offset: shiftedRect.topLeft,
@@ -370,7 +370,7 @@ class PlatformViewLayer extends Layer {
 
   @override
   ui.EngineLayer addToScene(ui.SceneBuilder builder, [ Offset layerOffset = Offset.zero ]) {
-    final Rect shiftedRect = rect.shift(layerOffset);
+    final Rect shiftedRect = layerOffset == Offset.zero ? rect : rect.shift(layerOffset);
     builder.addPlatformView(
       viewId,
       offset: shiftedRect.topLeft,
@@ -449,7 +449,8 @@ class PerformanceOverlayLayer extends Layer {
   @override
   ui.EngineLayer addToScene(ui.SceneBuilder builder, [ Offset layerOffset = Offset.zero ]) {
     assert(optionsMask != null);
-    builder.addPerformanceOverlay(optionsMask, overlayRect.shift(layerOffset));
+    final Rect shiftedOverlayRect = layerOffset == Offset.zero ? overlayRect : overlayRect.shift(layerOffset);
+    builder.addPerformanceOverlay(optionsMask, shiftedOverlayRect);
     builder.setRasterizerTracingThreshold(rasterizerThreshold);
     builder.setCheckerboardRasterCacheImages(checkerboardRasterCacheImages);
     builder.setCheckerboardOffscreenLayers(checkerboardOffscreenLayers);
@@ -1018,8 +1019,10 @@ class ClipRectLayer extends ContainerLayer {
       enabled = !debugDisableClipLayers;
       return true;
     }());
-    if (enabled)
-      builder.pushClipRect(clipRect.shift(layerOffset), clipBehavior: clipBehavior);
+    if (enabled) {
+      final Rect shiftedClipRect = layerOffset == Offset.zero ? clipRect : clipRect.shift(layerOffset);
+      builder.pushClipRect(shiftedClipRect, clipBehavior: clipBehavior);
+    }
     addChildrenToScene(builder, layerOffset);
     if (enabled)
       builder.pop();
@@ -1097,8 +1100,10 @@ class ClipRRectLayer extends ContainerLayer {
       enabled = !debugDisableClipLayers;
       return true;
     }());
-    if (enabled)
-      builder.pushClipRRect(clipRRect.shift(layerOffset), clipBehavior: clipBehavior);
+    if (enabled) {
+      final RRect shiftedClipRRect = layerOffset == Offset.zero ? clipRRect : clipRRect.shift(layerOffset);
+      builder.pushClipRRect(shiftedClipRRect, clipBehavior: clipBehavior);
+    }
     addChildrenToScene(builder, layerOffset);
     if (enabled)
       builder.pop();
@@ -1176,8 +1181,10 @@ class ClipPathLayer extends ContainerLayer {
       enabled = !debugDisableClipLayers;
       return true;
     }());
-    if (enabled)
-      builder.pushClipPath(clipPath.shift(layerOffset), clipBehavior: clipBehavior);
+    if (enabled) {
+      final Path shiftedPath = layerOffset == Offset.zero ? clipPath : clipPath.shift(layerOffset);
+      builder.pushClipPath(shiftedPath, clipBehavior: clipBehavior);
+    }
     addChildrenToScene(builder, layerOffset);
     if (enabled)
       builder.pop();
@@ -1414,7 +1421,8 @@ class ShaderMaskLayer extends ContainerLayer {
 
   @override
   ui.EngineLayer addToScene(ui.SceneBuilder builder, [ Offset layerOffset = Offset.zero ]) {
-    builder.pushShaderMask(shader, maskRect.shift(layerOffset), blendMode);
+    final Rect shiftedMaskRect = layerOffset == Offset.zero ? maskRect : maskRect.shift(layerOffset);
+    builder.pushShaderMask(shader, shiftedMaskRect, blendMode);
     addChildrenToScene(builder, layerOffset);
     builder.pop();
     return null; // this does not return an engine layer yet.
@@ -1590,7 +1598,7 @@ class PhysicalModelLayer extends ContainerLayer {
     }());
     if (enabled) {
       engineLayer = builder.pushPhysicalShape(
-        path: clipPath.shift(layerOffset),
+        path: layerOffset == Offset.zero ? clipPath : clipPath.shift(layerOffset),
         elevation: elevation,
         color: color,
         shadowColor: shadowColor,
