chrome/browser/extensions/image_loader.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CHROME_BROWSER_EXTENSIONS_IMAGE_LOADER_H_
   6 #define CHROME_BROWSER_EXTENSIONS_IMAGE_LOADER_H_
   7
   8 #include <map>
   9 #include <set>
  10
  11 #include "base/callback_forward.h"
  12 #include "base/gtest_prod_util.h"
  13 #include "base/memory/weak_ptr.h"
  14 #include "components/browser_context_keyed_service/browser_context_keyed_service.h"
  15 #include "extensions/common/extension_resource.h"
  16 #include "third_party/skia/include/core/SkBitmap.h"
  17 #include "ui/base/layout.h"
  18 #include "ui/gfx/size.h"
  19
  20 class Profile;
  21
  22 namespace gfx {
  23 class Image;
  24 }
  25
  26 namespace extensions {
  27
  28 class Extension;
  29
  30 // This class is responsible for asynchronously loading extension images and
  31 // calling a callback when an image is loaded.
  32 // The views need to load their icons asynchronously might be deleted before
  33 // the images have loaded. If you pass your callback using a weak_ptr, this
  34 // will make sure the callback won't be called after the view is deleted.
  35 class ImageLoader : public BrowserContextKeyedService {
  36  public:
  37   // Information about a singe image representation to load from an extension
  38   // resource.
  39   struct ImageRepresentation {
  40     // Enum values to indicate whether to resize loaded bitmap when it is larger
  41     // than |desired_size| or always resize it.
  42     enum ResizeCondition {
  43       RESIZE_WHEN_LARGER,
  44       ALWAYS_RESIZE,
  45     };
  46
  47     ImageRepresentation(const ExtensionResource& resource,
  48                         ResizeCondition resize_condition,
  49                         const gfx::Size& desired_size,
  50                         ui::ScaleFactor scale_factor);
  51     ~ImageRepresentation();
  52
  53     // Extension resource to load.
  54     ExtensionResource resource;
  55
  56     ResizeCondition resize_condition;
  57
  58     // When |resize_method| is ALWAYS_RESIZE or when the loaded image is larger
  59     // than |desired_size| it will be resized to these dimensions.
  60     gfx::Size desired_size;
  61
  62     // |scale_factor| is used to construct the loaded gfx::ImageSkia.
  63     ui::ScaleFactor scale_factor;
  64   };
  65
  66   struct LoadResult;
  67
  68   // Returns the instance for the given profile, or NULL if none. This is
  69   // a convenience wrapper around ImageLoaderFactory::GetForProfile.
  70   static ImageLoader* Get(Profile* profile);
  71
  72   ImageLoader();
  73   virtual ~ImageLoader();
  74
  75   // Checks whether image is a component extension resource. Returns false
  76   // if a given |resource| does not have a corresponding image in bundled
  77   // resources. Otherwise fills |resource_id|. This doesn't check if the
  78   // extension the resource is in is actually a component extension.
  79   static bool IsComponentExtensionResource(
  80       const base::FilePath& extension_path,
  81       const base::FilePath& resource_path,
  82       int* resource_id);
  83
  84   // Specify image resource to load. If the loaded image is larger than
  85   // |max_size| it will be resized to those dimensions. IMPORTANT NOTE: this
  86   // function may call back your callback synchronously (ie before it returns)
  87   // if the image was found in the cache.
  88   // Note this method loads a raw bitmap from the resource. All sizes given are
  89   // assumed to be in pixels.
  90   void LoadImageAsync(const extensions::Extension* extension,
  91                       const ExtensionResource& resource,
  92                       const gfx::Size& max_size,
  93                       const base::Callback<void(const gfx::Image&)>& callback);
  94
  95   // Same as LoadImage() above except it loads multiple images from the same
  96   // extension. This is used to load multiple resolutions of the same image
  97   // type.
  98   void LoadImagesAsync(const extensions::Extension* extension,
  99                        const std::vector<ImageRepresentation>& info_list,
 100                        const base::Callback<void(const gfx::Image&)>& callback);
 101
 102  private:
 103   base::WeakPtrFactory<ImageLoader> weak_ptr_factory_;
 104
 105   static void LoadImagesOnBlockingPool(
 106       const std::vector<ImageRepresentation>& info_list,
 107       const std::vector<SkBitmap>& bitmaps,
 108       std::vector<LoadResult>* load_result);
 109
 110   void ReplyBack(
 111       const std::vector<LoadResult>* load_result,
 112       const base::Callback<void(const gfx::Image&)>& callback);
 113 };
 114
 115 }  // namespace extensions
 116
 117 #endif  // CHROME_BROWSER_EXTENSIONS_IMAGE_LOADER_H_