Loading/Creating images for mutiple scale factors on the fly

ui/gfx/image/image_skia_unittest.cc

+// Copyright (c) 2012 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/gfx/image/image_skia.h"
+
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/gfx/image/image_skia_rep.h"
+#include "ui/gfx/image/image_skia_source.h"
+#include "ui/gfx/size.h"
+#include "ui/base/layout.h"
+
+namespace gfx {
+
+namespace {
+
+ImageSkiaRep CreateImage(const gfx::Size& size, ui::ScaleFactor scale_factor) {
+  SkBitmap bitmap;
+  gfx::Size pixel_size = size.Scale(ui::GetScaleFactorScale(scale_factor));
+  bitmap.setConfig(SkBitmap::kARGB_8888_Config,
+                   pixel_size.width(), pixel_size.height());
+  bitmap.allocPixels();
+  return ImageSkiaRep(bitmap, scale_factor);
+}
+
+class FixedSource : public ImageSkiaSource {
+ public:
+  FixedSource(const ImageSkiaRep& image) : image_(image) {}
+
+  virtual ImageSkiaRep GetImageForScale(ui::ScaleFactor scale_factor) OVERRIDE {
+    return image_;
+  }
+
+ private:
+  ImageSkiaRep image_;
+
+  DISALLOW_COPY_AND_ASSIGN(FixedSource);
+};
+
+class DynamicSource : public ImageSkiaSource {
+ public:
+  DynamicSource(const gfx::Size& size) : size_(size) {}
+
+  virtual ImageSkiaRep GetImageForScale(ui::ScaleFactor scale_factor) OVERRIDE {
+    return CreateImage(size_, scale_factor);
+  }
+
+ private:
+  gfx::Size size_;
+
+  DISALLOW_COPY_AND_ASSIGN(DynamicSource);
+};
+
+}  // namespace;
+
+typedef testing::Test ImageSkiaTest;
+
+TEST(ImageSkiaTest, FixedSource) {
+  ImageSkiaRep image(CreateImage(Size(100, 200), ui::SCALE_FACTOR_100P));
+  ImageSkia image_skia(new FixedSource(image), Size(100, 200));
+  EXPECT_EQ(0U, image_skia.image_reps().size());
+
+  const ImageSkiaRep& result_100p =
+      image_skia.GetRepresentation(ui::SCALE_FACTOR_100P);
+  EXPECT_EQ(100, result_100p.GetWidth());
+  EXPECT_EQ(200, result_100p.GetHeight());
+  EXPECT_EQ(ui::SCALE_FACTOR_100P, result_100p.scale_factor());
+  EXPECT_EQ(1U, image_skia.image_reps().size());
+
+  const ImageSkiaRep& result_200p =
+      image_skia.GetRepresentation(ui::SCALE_FACTOR_200P);
+
+  EXPECT_EQ(100, result_200p.GetWidth());
+  EXPECT_EQ(200, result_200p.GetHeight());
+  EXPECT_EQ(100, result_200p.pixel_width());
+  EXPECT_EQ(200, result_200p.pixel_height());
+  EXPECT_EQ(ui::SCALE_FACTOR_100P, result_200p.scale_factor());
+  EXPECT_EQ(2U, image_skia.image_reps().size());
+
+  // Get the representation again and make sure it doesn't
+  // generate new image skia rep.
+  image_skia.GetRepresentation(ui::SCALE_FACTOR_100P);
+  EXPECT_EQ(2U, image_skia.image_reps().size());
+  image_skia.GetRepresentation(ui::SCALE_FACTOR_200P);
+  EXPECT_EQ(2U, image_skia.image_reps().size());
+}
+
+TEST(ImageSkiaTest, DynamicSource) {
+  ImageSkia image_skia(new DynamicSource(Size(100, 200)), Size(100, 200));
+  EXPECT_EQ(0U, image_skia.image_reps().size());
+  const ImageSkiaRep& result_100p =
+      image_skia.GetRepresentation(ui::SCALE_FACTOR_100P);
+  EXPECT_EQ(100, result_100p.GetWidth());
+  EXPECT_EQ(200, result_100p.GetHeight());
+  EXPECT_EQ(ui::SCALE_FACTOR_100P, result_100p.scale_factor());
+  EXPECT_EQ(1U, image_skia.image_reps().size());
+
+  const ImageSkiaRep& result_200p =
+      image_skia.GetRepresentation(ui::SCALE_FACTOR_200P);
+  EXPECT_EQ(100, result_200p.GetWidth());
+  EXPECT_EQ(200, result_200p.GetHeight());
+  EXPECT_EQ(200, result_200p.pixel_width());
+  EXPECT_EQ(400, result_200p.pixel_height());
+  EXPECT_EQ(ui::SCALE_FACTOR_200P, result_200p.scale_factor());
+  EXPECT_EQ(2U, image_skia.image_reps().size());
+
+  // Get the representation again and make sure it doesn't
+  // generate new image skia rep.
+  image_skia.GetRepresentation(ui::SCALE_FACTOR_100P);
+  EXPECT_EQ(2U, image_skia.image_reps().size());
+  image_skia.GetRepresentation(ui::SCALE_FACTOR_200P);
+  EXPECT_EQ(2U, image_skia.image_reps().size());
+}
+
+}  // namespace gfx