This CL adds a new object: ImageSkiaRep

The object represents an SkBitmap and the scale factor that it is painted at.
The CL also changes the ImageSkia API to use ui::ScaleFactor instead of floats.

In Chromium, having this object is useful because it makes extracting an SkBitmap from an ImageSkia object and packing it back into an ImageSkia object easier.
In particular, this makes:
float scale_factor;
SkBitmap bitmap = input_image->GetBitmapForScale(1.0f, &scale_factor);
// do some work with the bitmap
gfx::ImageSkia output_image(bitmap, scale_factor);

into

gfx::ImageSkiaRep image_rep = input_image->GetRepresentation(ui::SCALE_FACTOR_100P);
// do some work with the image_rep
gfx::ImageSkia output_image(image_rep);

R=sky
TBR=sadrul for chrome/browser/chromeos/status

Review URL: https://chromiumcodereview.appspot.com/10448070

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@143940 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 51 insertions, 1 deletions

diff --git a/ui/base/layout.cc b/ui/base/layout.cc
index 451e9ac..ac4ee55 100644
--- a/ui/base/layout.cc
+++ b/ui/base/layout.cc
@@ -4,6 +4,9 @@
 
 #include "ui/base/layout.h"
 
+#include <cmath>
+#include <limits>
+
 #include "base/basictypes.h"
 #include "base/command_line.h"
 #include "base/logging.h"
@@ -68,8 +71,21 @@ bool UseTouchOptimizedUI() {
 }
 
 const float kScaleFactorScales[] = {1.0, 2.0};
-
+const size_t kScaleFactorScalesLength = arraysize(kScaleFactorScales);
+
+#if defined(OS_MACOSX)
+std::vector<ui::ScaleFactor>& GetSupportedScaleFactorsInternal() {
+  static std::vector<ui::ScaleFactor>* supported_scale_factors =
+      new std::vector<ui::ScaleFactor>();
+  if (supported_scale_factors->empty()) {
+      supported_scale_factors->push_back(ui::SCALE_FACTOR_100P);
+      supported_scale_factors->push_back(ui::SCALE_FACTOR_200P);
+  }
+  return *supported_scale_factors;
 }
+#endif  // OS_MACOSX
+
+}  // namespace
 
 namespace ui {
 
@@ -90,8 +106,42 @@ DisplayLayout GetDisplayLayout() {
 #endif
 }
 
+ScaleFactor GetScaleFactorFromScale(float scale) {
+  size_t closest_match = 0;
+  float smallest_diff =  std::numeric_limits<float>::max();
+  for (size_t i = 0; i < kScaleFactorScalesLength; ++i) {
+    float diff = std::abs(kScaleFactorScales[i] - scale);
+    if (diff < smallest_diff) {
+      closest_match = i;
+      smallest_diff = diff;
+    }
+  }
+  return static_cast<ui::ScaleFactor>(closest_match);
+}
+
 float GetScaleFactorScale(ScaleFactor scale_factor) {
   return kScaleFactorScales[scale_factor];
 }
 
+#if defined(OS_MACOSX)
+std::vector<ScaleFactor> GetSupportedScaleFactors() {
+  return GetSupportedScaleFactorsInternal();
+}
+
+namespace test {
+
+void SetSupportedScaleFactors(
+    const std::vector<ui::ScaleFactor>& scale_factors) {
+  std::vector<ui::ScaleFactor>& supported_scale_factors =
+      GetSupportedScaleFactorsInternal();
+  supported_scale_factors.clear();
+
+  for (size_t i = 0; i < scale_factors.size(); ++i)
+    supported_scale_factors.push_back(scale_factors[i]);
+}
+
+}  // namespace test
+
+#endif  // OS_MACOSX
+
 }  // namespace ui