Allows arbitrary scale factor in ImageSkia.

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 "base/command_line.h"
 #include "base/logging.h"
 #include "base/threading/simple_thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/gfx/image/image_skia_rep.h"
 #include "ui/gfx/image/image_skia_source.h"
 #include "ui/gfx/size.h"
+#include "ui/gfx/switches.h"
 
 // Duplicated from base/threading/non_thread_safe.h so that we can be
 // good citizens there and undef the macro.
 #if (!defined(NDEBUG) || defined(DCHECK_ALWAYS_ON))
 #define ENABLE_NON_THREAD_SAFE 1
 #else
 #define ENABLE_NON_THREAD_SAFE 0
 #endif
 
 namespace gfx {
@@ skipping 12 matching lines @@
   }
 
  private:
   ImageSkiaRep image_;
 
   DISALLOW_COPY_AND_ASSIGN(FixedSource);
 };
 
 class DynamicSource : public ImageSkiaSource {
  public:
-  DynamicSource(const gfx::Size& size) : size_(size) {}
+  DynamicSource(const gfx::Size& size)
+      : size_(size),
+        last_requested_scale_(0.0f) {}
 
   virtual ~DynamicSource() {
   }
 
   virtual ImageSkiaRep GetImageForScale(float scale) OVERRIDE {
+    last_requested_scale_ = scale;
     return gfx::ImageSkiaRep(size_, scale);
   }
 
+  float GetLastRequestedScaleAndReset() {
+    float result = last_requested_scale_;
+    last_requested_scale_ = 0.0f;
+    return result;
+  }
+
  private:
   gfx::Size size_;
+  float last_requested_scale_;
 
   DISALLOW_COPY_AND_ASSIGN(DynamicSource);
 };
 
 class NullSource: public ImageSkiaSource {
  public:
   NullSource() {
   }
 
   virtual ~NullSource() {
   }
 
   virtual ImageSkiaRep GetImageForScale(float scale) OVERRIDE {
     return gfx::ImageSkiaRep();
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(NullSource);
 };
 
+class ScopedScaleFactorSetter {
+ public:
+  ScopedScaleFactorSetter(const std::vector<float>& scales) {
+    old_scales_ = ImageSkia::GetSupportedScales();
+    ImageSkia::SetSupportedScales(scales);
+  }
+
+  ~ScopedScaleFactorSetter() {
+    ImageSkia::SetSupportedScales(old_scales_);
+  }
+
+ private:
+  std::vector<float> old_scales_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedScaleFactorSetter);
+};
+
 }  // namespace
 
 namespace test {
 class TestOnThread : public base::SimpleThread {
  public:
   explicit TestOnThread(ImageSkia* image_skia)
       : SimpleThread("image_skia_on_thread"),
         image_skia_(image_skia),
         can_read_(false),
         can_modify_(false) {
@@ skipping 281 matching lines @@
   EXPECT_TRUE(threadsafe_on_thread.can_read());
   EXPECT_FALSE(threadsafe_on_thread.can_modify());
   EXPECT_TRUE(image.CanRead());
   EXPECT_FALSE(image.CanModify());
 }
 #endif  // ENABLE_NON_THREAD_SAFE
 
 // Just in case we ever get lumped together with other compilation units.
 #undef ENABLE_NON_THREAD_SAFE
 
+TEST(ImageSkiaTest, ArbitraryScaleFactor) {
+  base::CommandLine::ForCurrentProcess()->AppendSwitch(
+      switches::kAllowArbitraryScaleFactorInImageSkia);
+
+  // Do not test if the ImageSkia doesn't support arbitrary scale factors.
+  if (!ImageSkia::IsDSFScalingInImageSkiaEnabled())
+    return;
+
+  // Sets the list of scale factors supported by resource bundle.
+  std::vector<float> supported_scale_factors;
+  supported_scale_factors.push_back(1.0f);
+  supported_scale_factors.push_back(2.0f);
+  ScopedScaleFactorSetter scoped_setter(supported_scale_factors);
+
+  // source is owned by |image|
+  DynamicSource* source = new DynamicSource(Size(100, 200));
+  ImageSkia image(source, gfx::Size(100, 200));
+
+  image.GetRepresentation(1.5f);
+  EXPECT_EQ(2.0f, source->GetLastRequestedScaleAndReset());
+  std::vector<ImageSkiaRep> image_reps = image.image_reps();
+  EXPECT_EQ(2u, image_reps.size());
+
+  std::vector<float> scale_factors;
+  for (size_t i = 0; i < image_reps.size(); ++i) {
+    scale_factors.push_back(image_reps[i].scale());
+  }
+  std::sort(scale_factors.begin(), scale_factors.end());
+  EXPECT_EQ(1.5f, scale_factors[0]);
+  EXPECT_EQ(2.0f, scale_factors[1]);
+
+  // Requesting 1.75 scale factor also falls back to 2.0f and rescale.
+  // However, the image already has the 2.0f data, so it won't fetch again.
+  image.GetRepresentation(1.75f);
+  EXPECT_EQ(0.0f, source->GetLastRequestedScaleAndReset());
+  image_reps = image.image_reps();
+  EXPECT_EQ(3u, image_reps.size());
+
+  scale_factors.clear();
+  for (size_t i = 0; i < image_reps.size(); ++i) {
+    scale_factors.push_back(image_reps[i].scale());
+  }
+  std::sort(scale_factors.begin(), scale_factors.end());
+  EXPECT_EQ(1.5f, scale_factors[0]);
+  EXPECT_EQ(1.75f, scale_factors[1]);
+  EXPECT_EQ(2.0f, scale_factors[2]);
+
+  // 1.25 is falled back to 1.0.
+  image.GetRepresentation(1.25f);
+  EXPECT_EQ(1.0f, source->GetLastRequestedScaleAndReset());
+  image_reps = image.image_reps();
+  EXPECT_EQ(5u, image_reps.size());
+
+  // Scale factor less than 1.0f will be falled back to 1.0f
+  image.GetRepresentation(0.75f);
+  EXPECT_EQ(0.0f, source->GetLastRequestedScaleAndReset());
+  image_reps = image.image_reps();
+  EXPECT_EQ(6u, image_reps.size());
+
+  scale_factors.clear();
+  for (size_t i = 0; i < image_reps.size(); ++i) {
+    scale_factors.push_back(image_reps[i].scale());
+  }
+  std::sort(scale_factors.begin(), scale_factors.end());
+  EXPECT_EQ(0.75f, scale_factors[0]);
+  EXPECT_EQ(1.0f, scale_factors[1]);
+  EXPECT_EQ(1.25f, scale_factors[2]);
+  EXPECT_EQ(1.5f, scale_factors[3]);
+  EXPECT_EQ(1.75f, scale_factors[4]);
+  EXPECT_EQ(2.0f, scale_factors[5]);
+
+  // Scale factor greater than 2.0f is falled back to 2.0f because it's not
+  // supported.
+  image.GetRepresentation(3.0f);
+  EXPECT_EQ(0.0f, source->GetLastRequestedScaleAndReset());
+  image_reps = image.image_reps();
+  EXPECT_EQ(7u, image_reps.size());
+}
+
 }  // namespace gfx