Expose array of bitmaps contained by gfx::Image similar to NSImage

ui/gfx/image/image_skia.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 <limits.h>
+#include <math.h>
+
+#include "base/logging.h"
+#include "base/stl_util.h"
+
+namespace gfx {
+
+ImageSkia::ImageSkia(const SkBitmap* bitmap)
+    : size_(bitmap->width(), bitmap->height()) {
+  DCHECK(bitmap);
+  DCHECK(!bitmap->isNull());
+  bitmaps_.push_back(bitmap);
+}
+
+ImageSkia::ImageSkia(const std::vector<const SkBitmap*>& bitmaps)
+    : bitmaps_(bitmaps) {
+  // Assume that the smallest bitmap represents 1x scale factor.
+  for (size_t i = 0; i < bitmaps_.size(); ++i) {
+    DCHECK(!bitmaps[i]->isNull());
+    gfx::Size bitmap_size(bitmaps_[i]->width(), bitmaps_[i]->height());
+    if (size_.IsEmpty() || bitmap_size.GetArea() < size_.GetArea())
+      size_ = bitmap_size;
+  }
+}
+
+ImageSkia::~ImageSkia() {
+  STLDeleteElements(&bitmaps_);
+}
+
+const SkBitmap* ImageSkia::GetBitmapForScaleFactor(
+    float device_scale_factor) const {
+  // Get the desired bitmap width and height given |device_scale_factor| and
+  // |size_| at 1x density.
+  float desired_width = size_.width() * device_scale_factor;
+  float desired_height = size_.height() * device_scale_factor;
+
+  size_t closest_index;
+  float smallest_diff = FLT_MAX;

[Robert Sesek, 2012/04/16 16:06:01]

std::numeric_limits

+  for (size_t i = 0; i < bitmaps_.size(); ++i) {
+    float diff = fabs(bitmaps_[i]->width() - desired_width) +

[Robert Sesek, 2012/04/16 16:06:01]

std::abs

+        fabs(bitmaps_[i]->height() - desired_height);
+    if (diff < smallest_diff) {
+      closest_index = i;
+      smallest_diff = diff;
+    }
+  }
+  return bitmaps_[closest_index];
+}
+
+}  // namespace gfx