Efficiently handle image layer scaling

webkit/compositor_bindings/web_layer_impl_fixed_bounds_unittest.cc

Index: webkit/compositor_bindings/web_layer_impl_fixed_bounds_unittest.cc
diff --git a/webkit/compositor_bindings/web_layer_impl_fixed_bounds_unittest.cc b/webkit/compositor_bindings/web_layer_impl_fixed_bounds_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..540afb508b1ff7bcbba36b5f3e1812fc7d6e883f
--- /dev/null
+++ b/webkit/compositor_bindings/web_layer_impl_fixed_bounds_unittest.cc
@@ -0,0 +1,190 @@
+// Copyright 2013 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/layer_tree_host_common.h"
+#include "cc/picture_image_layer.h"
+#include "cc/test/geometry_test_utils.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/WebKit/Source/Platform/chromium/public/WebFloatPoint.h"
+#include "third_party/WebKit/Source/Platform/chromium/public/WebSize.h"
+#include "third_party/WebKit/Source/Platform/chromium/public/WebTransformationMatrix.h"
+#include "third_party/skia/include/utils/SkMatrix44.h"
+#include "ui/gfx/point3_f.h"
+#include "webkit/compositor_bindings/web_layer_impl_fixed_bounds.h"
+
+using namespace WebKit;
+
+TEST(WebLayerImplFixedBoundsTest, IdentityBounds) {
+  scoped_ptr<WebLayerImplFixedBounds> layer(new WebLayerImplFixedBounds());
+  layer->setAnchorPoint(WebFloatPoint(0, 0));
+  layer->SetFixedBounds(gfx::Size(100, 100));
+  layer->setBounds(WebSize(100, 100));
+  EXPECT_EQ(WebSize(100, 100), layer->bounds());
+  EXPECT_EQ(gfx::Size(100, 100), layer->layer()->bounds());
+  EXPECT_EQ(gfx::Transform(), layer->layer()->transform());
+}
+
+gfx::Point3F TransformPoint(const gfx::Transform& transform,
+                            const gfx::Point3F& point) {
+  gfx::Point3F result = point;
+  transform.TransformPoint(result);
+  return result;
+}
+
+void CheckBoundsScaleSimple(WebLayerImplFixedBounds* layer,
+                            const WebSize& bounds,
+                            const gfx::Size& fixed_bounds) {
+  layer->setBounds(bounds);
+  layer->SetFixedBounds(fixed_bounds);
+
+  EXPECT_EQ(bounds, layer->bounds());
+  EXPECT_EQ(fixed_bounds, layer->layer()->bounds());
+  EXPECT_TRUE(layer->transform().isIdentity());
+  EXPECT_TRUE(layer->sublayerTransform().isIdentity());
+
+  // An arbitrary point to check the scale and transforms.
+  gfx::Point3F original_point(10, 20, 1);
+  gfx::Point3F scaled_point(
+      original_point.x() * bounds.width / fixed_bounds.width(),
+      original_point.y() * bounds.height / fixed_bounds.height(),
+      original_point.z());
+  // Test if the bounds scale is correctly applied in transform and
+  // sublayerTransform.
+  EXPECT_POINT3F_EQ(scaled_point,
+                    TransformPoint(layer->layer()->transform(),
+                                   original_point));
+  EXPECT_POINT3F_EQ(original_point,
+                    TransformPoint(layer->layer()->sublayerTransform(),
+                                   scaled_point));
+}
+
+TEST(WebLayerImplFixedBoundsTest, BoundsScaleSimple) {
+  scoped_ptr<WebLayerImplFixedBounds> layer(new WebLayerImplFixedBounds());
+  layer->setAnchorPoint(WebFloatPoint(0, 0));
+  CheckBoundsScaleSimple(layer.get(), WebSize(100, 200), gfx::Size(150, 250));
+  // Change fixedBounds.
+  CheckBoundsScaleSimple(layer.get(), WebSize(100, 200), gfx::Size(75, 100));
+  // Change bounds.
+  CheckBoundsScaleSimple(layer.get(), WebSize(300, 100), gfx::Size(75, 100));
+}
+
+void ExpectEqualLayerRectsInTarget(cc::Layer* layer1, cc::Layer* layer2) {
+  gfx::RectF layer1_rect_in_target(layer1->contentBounds());
+  layer1->drawTransform().TransformRect(&layer1_rect_in_target);
+
+  gfx::RectF layer2_rect_in_target(layer2->contentBounds());
+  layer2->drawTransform().TransformRect(&layer2_rect_in_target);
+
+  EXPECT_FLOAT_RECT_EQ(layer1_rect_in_target, layer2_rect_in_target);
+}
+
+void CompareFixedBoundsLayerAndNormalLayer(
+    const WebFloatPoint& anchor_point,
+    const gfx::Transform& transform,
+    const gfx::Transform& sublayer_transform) {
+  const gfx::Size kDeviceViewportSize(800, 600);
+  const float kDeviceScaleFactor = 2.f;
+  const float kPageScaleFactor = 1.5f;
+  const int kMaxTextureSize = 512;
+
+  WebSize bounds(150, 200);
+  WebFloatPoint position(20, 30);
+  WebSize sublayer_bounds(88, 99);
+  WebFloatPoint sublayer_position(50, 60);
+  gfx::Size fixed_bounds(160, 70);
+
+  scoped_ptr<WebLayerImplFixedBounds> root_layer(new WebLayerImplFixedBounds());
+
+  WebLayerImplFixedBounds* fixed_bounds_layer =
+      new WebLayerImplFixedBounds(cc::PictureImageLayer::create());
+  WebLayerImpl* sublayer_under_fixed_bounds_layer = new WebLayerImpl();
+  sublayer_under_fixed_bounds_layer->setBounds(sublayer_bounds);
+  sublayer_under_fixed_bounds_layer->setPosition(sublayer_position);
+  fixed_bounds_layer->addChild(sublayer_under_fixed_bounds_layer);
+  fixed_bounds_layer->setBounds(bounds);
+  fixed_bounds_layer->SetFixedBounds(fixed_bounds);
+  fixed_bounds_layer->setAnchorPoint(anchor_point);
+  fixed_bounds_layer->setTransform(transform.matrix());
+  fixed_bounds_layer->setSublayerTransform(sublayer_transform.matrix());
+  fixed_bounds_layer->setPosition(position);
+  root_layer->addChild(fixed_bounds_layer);
+
+  WebLayerImpl* normal_layer(new WebLayerImpl(cc::PictureImageLayer::create()));
+  WebLayerImpl* sublayer_under_normal_layer = new WebLayerImpl();
+  sublayer_under_normal_layer->setBounds(sublayer_bounds);
+  sublayer_under_normal_layer->setPosition(sublayer_position);
+
+  normal_layer->addChild(sublayer_under_normal_layer);
+  normal_layer->setBounds(bounds);
+  normal_layer->setAnchorPoint(anchor_point);
+  normal_layer->setTransform(transform.matrix());
+  normal_layer->setSublayerTransform(sublayer_transform.matrix());
+  normal_layer->setPosition(position);
+  root_layer->addChild(normal_layer);
+
+  std::vector<scoped_refptr<cc::Layer> > renderSurfaceLayerList;
+  cc::LayerTreeHostCommon::calculateDrawProperties(
+      root_layer->layer(),
+      kDeviceViewportSize,
+      kDeviceScaleFactor,
+      kPageScaleFactor,
+      kMaxTextureSize,
+      false,
+      renderSurfaceLayerList);
+  ExpectEqualLayerRectsInTarget(normal_layer->layer(),
+                                fixed_bounds_layer->layer());
+  ExpectEqualLayerRectsInTarget(sublayer_under_normal_layer->layer(),
+                                sublayer_under_fixed_bounds_layer->layer());
+
+  // Change of fixed bounds should not affect the target geometries.
+  fixed_bounds_layer->SetFixedBounds(gfx::Size(fixed_bounds.width() / 2,
+                                               fixed_bounds.height() * 2));
+  cc::LayerTreeHostCommon::calculateDrawProperties(
+      root_layer->layer(),
+      kDeviceViewportSize,
+      kDeviceScaleFactor,
+      kPageScaleFactor,
+      kMaxTextureSize,
+      false,
+      renderSurfaceLayerList);
+  ExpectEqualLayerRectsInTarget(normal_layer->layer(),
+                                fixed_bounds_layer->layer());
+  ExpectEqualLayerRectsInTarget(sublayer_under_normal_layer->layer(),
+                                sublayer_under_fixed_bounds_layer->layer());
+
+}
+
+// A black box test that ensures WebLayerImplFixedBounds won't change target
+// geometries. Simple case: identity transforms and zero anchor point.
+TEST(WebLayerImplFixedBoundsTest, CompareToWebLayerImplSimple) {
+  CompareFixedBoundsLayerAndNormalLayer(WebFloatPoint(0, 0),
+                                        gfx::Transform(),
+                                        gfx::Transform());
+}
+
+// A black box test that ensures WebLayerImplFixedBounds won't change target
+// geometries. Complex case: complex transforms and non-zero anchor point.
+TEST(WebLayerImplFixedBoundsTest, CompareToWebLayerImplComplex) {
+  gfx::Transform transform;
+  // These are arbitrary values that should not affect the results.
+  transform.Translate3d(50, 60, 70);
+  transform.Scale3d(2, 3, 4);
+  transform.RotateAbout(gfx::Vector3dF(33, 44, 55), 99);
+
+  gfx::Transform sublayer_transform;
+  // These are arbitrary values that should not affect the results.
+  sublayer_transform.Scale3d(1.1, 2.2, 3.3);
+  sublayer_transform.Translate3d(11, 22, 33);
+  sublayer_transform.RotateAbout(gfx::Vector3dF(10, 30, 20), 88);
+
+  CompareFixedBoundsLayerAndNormalLayer(WebFloatPoint(0, 0),
+                                        transform,
+                                        sublayer_transform);
+
+  // With non-zero anchor point, WebLayerImplFixedBounds will fall back to
+  // WebLayerImpl.
+  CompareFixedBoundsLayerAndNormalLayer(WebFloatPoint(0.4f, 0.6f),
+                                        transform,
+                                        sublayer_transform);
+}