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
12class SkBitmap;
13
14namespace gfx {
15class ImageSkia;
16class Size;
17}
18
19// Score which is smaller than the minimum score returned by
20// SelectFaviconFrames() or SelectFaviconFrameIndices().
21extern 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.
40gfx::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.
58void 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