cc: Move anti-aliasing decision to parent compositor.

cc/gl_renderer.cc

 // Copyright 2010 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.
 
 #include "cc/gl_renderer.h"
 
 #include <set>
 #include <string>
 #include <vector>
 
@@ skipping 760 matching lines @@
 
     gfx::QuadF localQuad;
     gfx::Transform deviceTransform = MathUtil::to2dTransform(frame.windowMatrix * frame.projectionMatrix * quad->quadTransform());
     if (!deviceTransform.IsInvertible())
         return;
 
     bool clipped = false;
     gfx::QuadF deviceLayerQuad = MathUtil::mapQuad(deviceTransform, gfx::QuadF(quad->visibleContentRect()), clipped);
     DCHECK(!clipped);
 
+    // TODO(reveman): Axis-aligned is not enough to avoid anti-aliasing.
+    // Bounding rectangle for quad also needs to be expressible as
+    // an integer rectangle. crbug.com/169374
+    bool isAxisAlignedInTarget = deviceLayerQuad.IsRectilinear();
+    bool useAA = !clipped && !isAxisAlignedInTarget && quad->IsAntialiased();
+
     TileProgramUniforms uniforms;
-    // For now, we simply skip anti-aliasing with the quad is clipped. This only happens
-    // on perspective transformed layers that go partially behind the camera.
-    if (quad->IsAntialiased() && !clipped) {
+    if (useAA) {
         if (quad->swizzle_contents)
             tileUniformLocation(tileProgramSwizzleAA(), uniforms);
         else
             tileUniformLocation(tileProgramAA(), uniforms);
     } else {
         if (quad->ShouldDrawWithBlending()) {
             if (quad->swizzle_contents)
                 tileUniformLocation(tileProgramSwizzle(), uniforms);
             else
                 tileUniformLocation(tileProgram(), uniforms);
         } else {
             if (quad->swizzle_contents)
                 tileUniformLocation(tileProgramSwizzleOpaque(), uniforms);
             else
                 tileUniformLocation(tileProgramOpaque(), uniforms);
         }
     }
 
     setUseProgram(uniforms.program);
     GLC(context(), context()->uniform1i(uniforms.samplerLocation, 0));
     bool scaled = (texToGeomScaleX != 1 || texToGeomScaleY != 1);
     GLenum filter = (quad->IsAntialiased() || scaled || !quad->quadTransform().IsIdentityOrIntegerTranslation()) ? GL_LINEAR : GL_NEAREST;
     ResourceProvider::ScopedSamplerGL quadResourceLock(m_resourceProvider, quad->resource_id, GL_TEXTURE_2D, filter);
 
-    bool useAA = !clipped && quad->IsAntialiased();
     if (useAA) {
         LayerQuad deviceLayerBounds = LayerQuad(gfx::QuadF(deviceLayerQuad.BoundingBox()));
         deviceLayerBounds.inflateAntiAliasingDistance();
 
         LayerQuad deviceLayerEdges = LayerQuad(deviceLayerQuad);
         deviceLayerEdges.inflateAntiAliasingDistance();
 
         float edge[24];
         deviceLayerEdges.toFloatArray(edge);
         deviceLayerBounds.toFloatArray(&edge[12]);
@@ skipping 975 matching lines @@
 
     releaseRenderPassTextures();
 }
 
 bool GLRenderer::isContextLost()
 {
     return (m_context->getGraphicsResetStatusARB() != GL_NO_ERROR);
 }
 
 }  // namespace cc