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      1 // Copyright 2014 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 COMPONENTS_FAVICON_BASE_SELECT_FAVICON_FRAMES_H_
      6 #define COMPONENTS_FAVICON_BASE_SELECT_FAVICON_FRAMES_H_
      7 
      8 #include <vector>
      9 
     10 #include "base/basictypes.h"
     11 
     12 class SkBitmap;
     13 
     14 namespace gfx {
     15 class ImageSkia;
     16 class Size;
     17 }
     18 
     19 // Score which is smaller than the minimum score returned by
     20 // SelectFaviconFrames() or SelectFaviconFrameIndices().
     21 extern const float kSelectFaviconFramesInvalidScore;
     22 
     23 // Takes a list of all bitmaps found in a .ico file, and creates an
     24 // ImageSkia that's |desired_size_in_dip| x |desired_size_in_dip| big.
     25 // Bitmaps are selected by using |SelectFaviconFrameIndices| and the
     26 // platform's supported favicon scales (favicon_base::GetFaviconScales()).
     27 // If |desired_size_in_dip| is 0, the largest bitmap is returned unmodified.
     28 // |original_sizes| are the original sizes of the bitmaps. (For instance,
     29 // WebContents::DownloadImage() does resampling if it is passed a max size.)
     30 // If score is non-NULL, it receives a score between 0 (bad) and 1 (good)
     31 // that describes how well |bitmaps| were able to produce an image at
     32 // |desired_size_in_dip| for |favicon_scales|.
     33 // The score is arbitrary, but it's best for exact size matches,
     34 // and gets worse the more resampling needs to happen.
     35 // If the resampling algorithm is modified, the resampling done in
     36 // FaviconUtil::SelectFaviconFramesFromPNGs() should probably be modified too as
     37 // it inspired by this method.
     38 // If an unsupported scale (not in the favicon_base::GetFaviconScales())
     39 // is requested, the ImageSkia will automatically scales using lancoz3.
     40 gfx::ImageSkia CreateFaviconImageSkia(
     41     const std::vector<SkBitmap>& bitmaps,
     42     const std::vector<gfx::Size>& original_sizes,
     43     int desired_size_in_dip,
     44     float* score);
     45 
     46 // Takes a list of the pixel sizes of a favicon's favicon bitmaps and returns
     47 // the indices of the best sizes to use to create an ImageSkia with
     48 // ImageSkiaReps with edge sizes |desired_sizes|. If '0' is one of
     49 // |desired_sizes|, the index of the largest size is returned. If |score| is
     50 // non-NULL, |score| is set to a value between 0 (bad) and 1 (good) that
     51 // describes how well the bitmap data with the sizes at |best_indices| will
     52 // produce the ImageSkia. The score is arbitrary, but it's best for exact
     53 // matches, and gets worse the more resampling needs to happen.
     54 // TODO(pkotwicz): Change API so that |desired_sizes| being empty indicates
     55 // that the index of the largest size is requested.
     56 // TODO(pkotwicz): Remove callers of this method for which |frame_pixel_sizes|
     57 // are the sizes of the favicon bitmaps after they were resized.
     58 void SelectFaviconFrameIndices(const std::vector<gfx::Size>& frame_pixel_sizes,
     59                                const std::vector<int>& desired_sizes,
     60                                std::vector<size_t>* best_indices,
     61                                float* score);
     62 
     63 #endif  // COMPONENTS_FAVICON_BASE_SELECT_FAVICON_FRAMES_H_
     64