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

ui/gfx/image/image_skia.h

+// 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.
+
+#ifndef UI_GFX_IMAGE_IMAGE_SKIA_H_
+#define UI_GFX_IMAGE_IMAGE_SKIA_H_
+#pragma once
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/size.h"
+
+namespace gfx {
+
+// Container for the same image at different densities, similar to NSImage.
+// Smallest image is assumed to represent 1x density.
+
+// ImageSkia should be used for caching and drawing images of different
+// densities. It should not be used as an SkBitmap wrapper.
+class UI_EXPORT ImageSkia {
+ public:
+  explicit ImageSkia(const SkBitmap* bitmap);
+  explicit ImageSkia(const std::vector<const SkBitmap*>& bitmaps);
+  ~ImageSkia();
+
+  // Build mipmap at time of next call to |DrawToCanvasInt|.
+  void BuildMipMap();
+
+  // Draws the image with the origin at the specified location. The upper left
+  // corner of the image is rendered at the specified location.
+  void DrawToCanvasInt(Canvas* canvas, int x, int y);
+
+  // Draws the image with the origin at the specified location, using the
+  // specified paint. The upper left corner of the image is rendered at the
+  // specified location.
+  void DrawToCanvasInt(Canvas* canvas,
+                       int x, int y,
+                       const SkPaint& paint);
+
+  // Draws a portion of the image in the specified location. The src parameters
+  // correspond to the region of the image to draw in the region defined
+  // by the dest coordinates.
+  //
+  // If the width or height of the source differs from that of the destination,
+  // the image will be scaled. When scaling down, it is highly recommended
+  // that you call BuildMipMap() on your image to ensure that it has
+  // a mipmap, which will result in much higher-quality output. Set |filter| to
+  // use filtering for bitmaps, otherwise the nearest-neighbor algorithm is used
+  // for resampling.
+  //
+  // An optional custom SkPaint can be provided.
+  void DrawToCanvasInt(Canvas* canvas,
+                       int src_x, int src_y, int src_w, int src_h,
+                       int dest_x, int dest_y, int dest_w, int dest_h,
+                       bool filter);
+  void DrawToCanvasInt(Canvas* canvas,
+                       int src_x, int src_y, int src_w, int src_h,
+                       int dest_x, int dest_y, int dest_w, int dest_h,
+                       bool filter,
+                       const SkPaint& paint);
+
+  // Returns true if |size_| is empty.
+  bool IsZeroSized() const { return size_.IsEmpty(); }
+
+  // Width and height of image in DIP coordinate system.
+  int width() const { return size_.width(); }
+  int height() const { return size_.height(); }
+
+  // Returns a vector with the SkBitmaps contained in this object.
+  const std::vector<const SkBitmap*>& bitmaps() const { return bitmaps_; }
+
+ private:
+  // Returns the bitmap whose density best matches |x_scale_factor| and
+  // |y_scale_factor|.
+  const SkBitmap* GetBitmapForScale(float x_scale_factor,
+                                    float y_scale_factor) const;
+
+  std::vector<const SkBitmap*> bitmaps_;
+  gfx::Size size_;
+  bool mip_map_build_pending_;
+
+  DISALLOW_COPY_AND_ASSIGN(ImageSkia);
+};
+
+}  // namespace gfx
+
+#endif  // UI_GFX_IMAGE_IMAGE_SKIA_H_