Implements core logic for Pixel Canvas

ui/compositor/paint_context_unittest.cc

Index: ui/compositor/paint_context_unittest.cc
diff --git a/ui/compositor/paint_context_unittest.cc b/ui/compositor/paint_context_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..5efd7194b294dc756787850b9ec3d7fa14191d11
--- /dev/null
+++ b/ui/compositor/paint_context_unittest.cc
@@ -0,0 +1,235 @@
+// Copyright 2017 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 "ui/compositor/paint_context.h"
+
+#include <vector>
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "cc/base/region.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/gfx/geometry/rect.h"
+#include "ui/gfx/geometry/size.h"
+
+namespace ui {
+namespace {
+
+typedef testing::Test PaintContextTest;
+
+// Device scale factors
+constexpr float DSF100 = 1.f;
+constexpr float DSF125 = 1.25f;
+constexpr float DSF150 = 1.5f;
+constexpr float DSF160 = 1.6f;
+constexpr float DSF166 = 1.66f;
+
+const std::vector<float> kDsfList = {DSF100, DSF125, DSF150, DSF160, DSF166};
+
+const gfx::Size kLayerSize(123, 456);
+
+//  ___________
+// |     1     |
+// |___________|
+// | 3 | 4 | 5 | <-- 2
+// |___|___|___|
+// |   7   | 8 | <-- 6
+// |_______|___|
+const gfx::Rect r_0(kLayerSize);
+
+const gfx::Rect r_0_1(0, 0, 123, 152);
+
+const gfx::Rect r_0_2(0, 152, 123, 152);
+const gfx::Rect r_2_3(0, 0, 41, 152);
+const gfx::Rect r_2_4(41, 0, 41, 152);
+const gfx::Rect r_2_5(82, 0, 41, 152);
+
+const gfx::Rect r_0_6(0, 304, 123, 152);
+const gfx::Rect r_6_7(0, 0, 82, 152);
+const gfx::Rect r_6_8(82, 0, 41, 152);
+
+// Returns as DisplayItemList with the pixel canvas enabled or disabled based on
+// |pixel_canvas_enabled|.
+cc::DisplayItemList* GetDisplayItemList(bool pixel_canvas_enabled) {
+  cc::DisplayItemList* display_item_list = new cc::DisplayItemList;
+  display_item_list->set_pixel_canvas_enabled(pixel_canvas_enabled);
+  return std::move(display_item_list);
+}
+
+//  ___________
+// |     1     |
+// |___________|
+// | 3 | 4 | 5 | <-- 2
+// |___|___|___|
+// |   7   | 8 | <-- 6
+// |_______|___|
+// Returns the following arrangement of contexts for the given |dsf|
+std::vector<PaintContext*> GetPaintContextSetup(bool pixel_canvas_enabled,
+                                                float dsf,
+                                                const gfx::Rect& invd_rect) {
+  std::vector<PaintContext*> contexts(9);
+  contexts[0] = new PaintContext(GetDisplayItemList(pixel_canvas_enabled), dsf,
+                                 invd_rect, kLayerSize);
+
+  contexts[1] =
+      new PaintContext(*contexts[0], r_0_1, PaintContext::SCALE_TO_FIT);
+
+  contexts[2] =
+      new PaintContext(*contexts[0], r_0_2, PaintContext::SCALE_TO_FIT);
+  contexts[3] =
+      new PaintContext(*contexts[2], r_2_3, PaintContext::SCALE_TO_FIT);
+  contexts[4] =
+      new PaintContext(*contexts[2], r_2_4, PaintContext::SCALE_TO_FIT);
+  contexts[5] =
+      new PaintContext(*contexts[2], r_2_5, PaintContext::SCALE_TO_FIT);
+
+  contexts[6] =
+      new PaintContext(*contexts[0], r_0_6, PaintContext::SCALE_TO_FIT);
+  contexts[7] =
+      new PaintContext(*contexts[6], r_6_7, PaintContext::SCALE_TO_FIT);
+  contexts[8] =
+      new PaintContext(*contexts[6], r_6_8, PaintContext::SCALE_TO_FIT);
+
+  return contexts;
+}
+
+// Verifies that the child contexts completely cover the parent context bounds.
+void VerifyContextCoversParentContext(PaintContext* parent_context,
+                                      std::vector<PaintContext*> contexts) {
+  cc::Region remaining(gfx::Rect(parent_context->pixel_size()));
+  int times_empty = 0;
+  for (auto* context : contexts) {
+    const gfx::Rect& child_context_bounds = context->pixel_bounds();
+    EXPECT_TRUE(remaining.Contains(child_context_bounds))
+        << "Remaining: " << remaining.ToString()
+        << " context pixel bounds: " << child_context_bounds.ToString();
+    remaining.Subtract(child_context_bounds);
+    times_empty += remaining.IsEmpty();
+  }
+  EXPECT_EQ(times_empty, 1);
+}
+
+void VerifyPixelCanvasCornerScaling(std::vector<PaintContext*> contexts) {
+  // context 1, context 2 and context 6 should completely cover context 0.
+  std::vector<PaintContext*> child_contexts;
+  child_contexts.push_back(contexts[1]);
+  child_contexts.push_back(contexts[2]);
+  child_contexts.push_back(contexts[6]);
+  VerifyContextCoversParentContext(contexts[0], child_contexts);
+  child_contexts.clear();
+
+  // Context 3,4 and 5 should completely cover context 2.
+  child_contexts.push_back(contexts[3]);
+  child_contexts.push_back(contexts[4]);
+  child_contexts.push_back(contexts[5]);
+  VerifyContextCoversParentContext(contexts[2], child_contexts);
+  child_contexts.clear();
+
+  // Context 7 and 8 should completely cover context 6.
+  child_contexts.push_back(contexts[7]);
+  child_contexts.push_back(contexts[8]);
+  VerifyContextCoversParentContext(contexts[6], child_contexts);
+  child_contexts.clear();
+}
+
+void ClearAllContexts(std::vector<PaintContext*> contexts) {
+  for (auto* context : contexts)
+    delete context;
+}
+
+void VerifyPixelSizesAreSameAsDIPSize(std::vector<PaintContext*> contexts) {
+  EXPECT_EQ(contexts[0]->pixel_size(), r_0.size());
+
+  EXPECT_EQ(contexts[1]->pixel_size(), r_0_1.size());
+
+  EXPECT_EQ(contexts[2]->pixel_size(), r_0_2.size());
+  EXPECT_EQ(contexts[3]->pixel_size(), r_2_3.size());
+  EXPECT_EQ(contexts[4]->pixel_size(), r_2_4.size());
+  EXPECT_EQ(contexts[5]->pixel_size(), r_2_5.size());
+
+  EXPECT_EQ(contexts[6]->pixel_size(), r_0_6.size());
+  EXPECT_EQ(contexts[7]->pixel_size(), r_6_7.size());
+  EXPECT_EQ(contexts[8]->pixel_size(), r_6_8.size());
+}
+
+void VerifyInvalidationRects(float dsf, bool pixel_canvas_enabled) {
+  std::vector<gfx::Rect> invalidation_rects = {
+      gfx::Rect(0, 0, 123, 41),     // Intersects with 0 & 1.
+      gfx::Rect(0, 76, 60, 152),    // Intersects 0, 1, 2, 3 & 4.
+      gfx::Rect(41, 152, 41, 152),  // Intersects with 0, 2 & 4.
+      gfx::Rect(80, 320, 4, 4),     // Intersects with 0, 6, 7 & 8.
+      gfx::Rect(40, 151, 43, 154),  // Intersects all
+      gfx::Rect(82, 304, 1, 1),     // Intersects with 0, 6 & 8.
+      gfx::Rect(81, 303, 2, 2)      // Intersects with 0, 2, 4, 5, 6, 7, 8
+  };
+
+  std::vector<std::vector<int>> repaint_context_indices = {
+      std::vector<int>{0, 1},
+      std::vector<int>{0, 1, 2, 3, 4},
+      std::vector<int>{0, 2, 4},
+      std::vector<int>{0, 6, 7, 8},
+      std::vector<int>{0, 1, 2, 3, 4, 5, 6, 7, 8},
+      std::vector<int>{0, 6, 8},
+      std::vector<int>{0, 2, 4, 5, 6, 7, 8}};
+
+  std::vector<PaintContext*> contexts;
+
+  EXPECT_EQ(repaint_context_indices.size(), invalidation_rects.size());
+  for (size_t i = 0; i < invalidation_rects.size(); i++) {
+    contexts =
+        GetPaintContextSetup(pixel_canvas_enabled, dsf, invalidation_rects[i]);
+    for (size_t j = 0; j < repaint_context_indices[i].size(); j++)
+      EXPECT_TRUE(contexts[repaint_context_indices[i][j]]->ShouldRepaint());
+    ClearAllContexts(contexts);
+  }
+}
+
+}  // namespace
+
+TEST_F(PaintContextTest, CornerScalingPixelCanvasEnabled) {
+  std::vector<PaintContext*> contexts;
+  for (float dsf : kDsfList) {
+    contexts = GetPaintContextSetup(true, dsf, gfx::Rect());
+    VerifyPixelCanvasCornerScaling(contexts);
+    ClearAllContexts(contexts);
+  }
+
+  // More accurate testing for 1.25 dsf
+  contexts = GetPaintContextSetup(true, DSF125, gfx::Rect());
+  VerifyPixelCanvasCornerScaling(contexts);
+  EXPECT_EQ(contexts[0]->pixel_size(), gfx::Size(154, 570));
+
+  EXPECT_EQ(contexts[1]->pixel_size(), gfx::Size(154, 190));
+
+  EXPECT_EQ(contexts[2]->pixel_bounds(), gfx::Rect(0, 190, 154, 190));
+  EXPECT_EQ(contexts[3]->pixel_size(), gfx::Size(51, 190));
+  EXPECT_EQ(contexts[4]->pixel_bounds(), gfx::Rect(51, 0, 52, 190));
+  EXPECT_EQ(contexts[5]->pixel_bounds(), gfx::Rect(103, 0, 51, 190));
+
+  EXPECT_EQ(contexts[6]->pixel_bounds(), gfx::Rect(0, 380, 154, 190));
+  EXPECT_EQ(contexts[7]->pixel_size(), gfx::Size(103, 190));
+  EXPECT_EQ(contexts[8]->pixel_bounds(), gfx::Rect(103, 0, 51, 190));
+  ClearAllContexts(contexts);
+}
+
+TEST_F(PaintContextTest, ScalingWithPixelCanvasDisabled) {
+  // With dsf as 1, there should be no scaling and size should be same.
+  std::vector<PaintContext*> contexts =
+      GetPaintContextSetup(false, DSF100, gfx::Rect());
+  for (float dsf : kDsfList) {
+    contexts = GetPaintContextSetup(false, dsf, gfx::Rect());
+    VerifyPixelCanvasCornerScaling(contexts);
+    VerifyPixelSizesAreSameAsDIPSize(contexts);
+    ClearAllContexts(contexts);
+  }
+}
+
+TEST_F(PaintContextTest, Invalidation) {
+  for (float dsf : kDsfList) {
+    VerifyInvalidationRects(dsf, false);
+    VerifyInvalidationRects(dsf, true);
+  }
+}
+
+}  // namespace ui