chrome/browser/manifest/manifest_icon_selector.h

   1 // Copyright 2015 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_MANIFEST_MANIFEST_ICON_SELECTOR_H_
   6 #define CHROME_BROWSER_MANIFEST_MANIFEST_ICON_SELECTOR_H_
   7
   8 #include "base/basictypes.h"
   9 #include "content/public/common/manifest.h"
  10 #include "url/gurl.h"
  11
  12 namespace content {
  13 class WebContents;
  14 }  // namespace content
  15
  16 namespace IPC {
  17 class Message;
  18 }  // namespace IPC
  19
  20 namespace gfx {
  21 class Screen;
  22 }
  23
  24 // Selects the icon most closely matching the size constraints.  This follows
  25 // very basic heuristics -- improvements are welcome.
  26 class ManifestIconSelector {
  27  public:
  28   // Runs the algorithm to find the best matching icon in the icons listed in
  29   // the Manifest.
  30   //
  31   // Size is defined in Android's density-independent pixels (dp):
  32   // http://developer.android.com/guide/practices/screens_support.html
  33   // If/when this class is generalized, it may be a good idea to switch this to
  34   // taking in pixels, instead.
  35   //
  36   // The icon returned will have a minimum size of an image one density bucket
  37   // smaller than the device denisity * preferred_icon_size_in_dp.
  38   //
  39   // Returns the icon url if a suitable icon is found. An empty URL otherwise.
  40   static GURL FindBestMatchingIcon(
  41       const std::vector<content::Manifest::Icon>& icons,
  42       float preferred_icon_size_in_dp,
  43       const gfx::Screen* screen);
  44
  45  private:
  46   ManifestIconSelector(float preferred_icon_size_in_pixels,
  47                        float minimum_icon_size_in_pixels);
  48   virtual ~ManifestIconSelector() {}
  49
  50   // Runs the algorithm to find the best matching icon in the icons listed in
  51   // the Manifest.
  52   // Returns the icon url if a suitable icon is found. An empty URL otherwise.
  53   int FindBestMatchingIcon(
  54       const std::vector<content::Manifest::Icon>& icons,
  55       float density);
  56
  57   // Runs an algorithm only based on icon declared sizes. It will try to find
  58   // size that is the closest to preferred_icon_size_in_pixels_ but bigger than
  59   // preferred_icon_size_in_pixels_ if possible.
  60   // Returns the index of a suitable icon if one is found. -1 otherwise.
  61   int FindBestMatchingIconForDensity(
  62       const std::vector<content::Manifest::Icon>& icons,
  63       float density);
  64
  65   // Returns whether the |preferred_icon_size_in_pixels_| is in |sizes|.
  66   bool IconSizesContainsPreferredSize(const std::vector<gfx::Size>& sizes);
  67
  68   // Returns whether a size bigger than |minimun_icon_size_in_pixels_| is in
  69   // |sizes|.
  70   bool IconSizesContainsBiggerThanMinimumSize(
  71       const std::vector<gfx::Size>& sizes);
  72
  73   // Returns an array containing the items in |icons| without the unsupported
  74   // image MIME types.
  75   static std::vector<content::Manifest::Icon> FilterIconsByType(
  76       const std::vector<content::Manifest::Icon>& icons);
  77
  78   // Returns whether the 'any' (ie. gfx::Size(0,0)) is in |sizes|.
  79   static bool IconSizesContainsAny(const std::vector<gfx::Size>& sizes);
  80
  81   const int preferred_icon_size_in_pixels_;
  82   const int minimum_icon_size_in_pixels_;
  83
  84   friend class ManifestIconSelectorTest;
  85
  86   DISALLOW_COPY_AND_ASSIGN(ManifestIconSelector);
  87 };
  88
  89 #endif  // CHROME_BROWSER_MANIFEST_MANIFEST_ICON_SELECTOR_H_