Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(257)

Side by Side Diff: ui/gfx/color_analysis.h

Issue 289283004: Add ability to constrain dominant color selection to a HSL range. (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/src
Patch Set: address comments Created 6 years, 7 months ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View unified diff | Download patch | Annotate | Revision Log
OLDNEW
1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 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 2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file. 3 // found in the LICENSE file.
4 4
5 #ifndef UI_GFX_COLOR_ANALYSIS_H_ 5 #ifndef UI_GFX_COLOR_ANALYSIS_H_
6 #define UI_GFX_COLOR_ANALYSIS_H_ 6 #define UI_GFX_COLOR_ANALYSIS_H_
7 7
8 #include "base/basictypes.h" 8 #include "base/basictypes.h"
9 #include "base/compiler_specific.h" 9 #include "base/compiler_specific.h"
10 #include "base/memory/ref_counted.h" 10 #include "base/memory/ref_counted.h"
11 #include "base/memory/ref_counted_memory.h" 11 #include "base/memory/ref_counted_memory.h"
12 #include "third_party/skia/include/core/SkColor.h" 12 #include "third_party/skia/include/core/SkColor.h"
13 #include "ui/gfx/gfx_export.h" 13 #include "ui/gfx/gfx_export.h"
14 #include "ui/gfx/matrix3_f.h" 14 #include "ui/gfx/matrix3_f.h"
15 15
16 class SkBitmap; 16 class SkBitmap;
17 17
18 namespace color_utils { 18 namespace color_utils {
19 19
20 struct HSL;
21
20 // This class exposes the sampling method to the caller, which allows 22 // This class exposes the sampling method to the caller, which allows
21 // stubbing out for things like unit tests. Might be useful to pass more 23 // stubbing out for things like unit tests. Might be useful to pass more
22 // arguments into the GetSample method in the future (such as which 24 // arguments into the GetSample method in the future (such as which
23 // cluster is being worked on, etc.). 25 // cluster is being worked on, etc.).
24 // 26 //
25 // Note: Samplers should be deterministic, as the same image may be analyzed 27 // Note: Samplers should be deterministic, as the same image may be analyzed
26 // twice with two sampler instances and the results displayed side-by-side 28 // twice with two sampler instances and the results displayed side-by-side
27 // to the user. 29 // to the user.
28 class GFX_EXPORT KMeanImageSampler { 30 class GFX_EXPORT KMeanImageSampler {
29 public: 31 public:
(...skipping 20 matching lines...) Expand all
50 // Returns the color in an ARGB |image| that is closest in RGB-space to the 52 // Returns the color in an ARGB |image| that is closest in RGB-space to the
51 // provided |color|. Exported for testing. 53 // provided |color|. Exported for testing.
52 GFX_EXPORT SkColor FindClosestColor(const uint8_t* image, int width, int height, 54 GFX_EXPORT SkColor FindClosestColor(const uint8_t* image, int width, int height,
53 SkColor color); 55 SkColor color);
54 56
55 // Returns an SkColor that represents the calculated dominant color in the 57 // Returns an SkColor that represents the calculated dominant color in the
56 // image. 58 // image.
57 // This uses a KMean clustering algorithm to find clusters of pixel colors in 59 // This uses a KMean clustering algorithm to find clusters of pixel colors in
58 // RGB space. 60 // RGB space.
59 // |png/bitmap| represents the data of a png/bitmap encoded image. 61 // |png/bitmap| represents the data of a png/bitmap encoded image.
60 // |darkness_limit| represents the minimum sum of the RGB components that is 62 // |lower_bound| represents the minimum bound of HSL values to allow.
61 // acceptable as a color choice. This can be from 0 to 765. 63 // |upper_bound| represents the maximum bound of HSL values to allow.
62 // |brightness_limit| represents the maximum sum of the RGB components that is 64 // See color_utils::IsWithinHSLRange() for description of these bounds.
63 // acceptable as a color choice. This can be from 0 to 765.
64 // 65 //
65 // RGB KMean Algorithm (N clusters, M iterations): 66 // RGB KMean Algorithm (N clusters, M iterations):
66 // 1.Pick N starting colors by randomly sampling the pixels. If you see a 67 // 1.Pick N starting colors by randomly sampling the pixels. If you see a
67 // color you already saw keep sampling. After a certain number of tries 68 // color you already saw keep sampling. After a certain number of tries
68 // just remove the cluster and continue with N = N-1 clusters (for an image 69 // just remove the cluster and continue with N = N-1 clusters (for an image
69 // with just one color this should devolve to N=1). These colors are the 70 // with just one color this should devolve to N=1). These colors are the
70 // centers of your N clusters. 71 // centers of your N clusters.
71 // 2.For each pixel in the image find the cluster that it is closest to in RGB 72 // 2.For each pixel in the image find the cluster that it is closest to in RGB
72 // space. Add that pixel's color to that cluster (we keep a sum and a count 73 // space. Add that pixel's color to that cluster (we keep a sum and a count
73 // of all of the pixels added to the space, so just add it to the sum and 74 // of all of the pixels added to the space, so just add it to the sum and
74 // increment count). 75 // increment count).
75 // 3.Calculate the new cluster centroids by getting the average color of all of 76 // 3.Calculate the new cluster centroids by getting the average color of all of
76 // the pixels in each cluster (dividing the sum by the count). 77 // the pixels in each cluster (dividing the sum by the count).
77 // 4.See if the new centroids are the same as the old centroids. 78 // 4.See if the new centroids are the same as the old centroids.
78 // a) If this is the case for all N clusters than we have converged and 79 // a) If this is the case for all N clusters than we have converged and
79 // can move on. 80 // can move on.
80 // b) If any centroid moved, repeat step 2 with the new centroids for up 81 // b) If any centroid moved, repeat step 2 with the new centroids for up
81 // to M iterations. 82 // to M iterations.
82 // 5.Once the clusters have converged or M iterations have been tried, sort 83 // 5.Once the clusters have converged or M iterations have been tried, sort
83 // the clusters by weight (where weight is the number of pixels that make up 84 // the clusters by weight (where weight is the number of pixels that make up
84 // this cluster). 85 // this cluster).
85 // 6.Going through the sorted list of clusters, pick the first cluster with the 86 // 6.Going through the sorted list of clusters, pick the first cluster with the
86 // largest weight that's centroid fulfills the equation 87 // largest weight that's centroid falls between |lower_bound| and
87 // |darkness_limit| < SUM(R, G, B) < |brightness_limit|. Return that color. 88 // |upper_bound|. Return that color.
88 // If no color fulfills that requirement return the color with the largest 89 // If no color fulfills that requirement return the color with the largest
89 // weight regardless of whether or not it fulfills the equation above. 90 // weight regardless of whether or not it fulfills the equation above.
90 // 91 GFX_EXPORT SkColor
91 // Note: Switching to HSV space did not improve the results of this algorithm 92 CalculateKMeanColorOfPNG(scoped_refptr<base::RefCountedMemory> png,
92 // for typical favicon images. 93 const HSL& lower_bound,
93 GFX_EXPORT SkColor CalculateKMeanColorOfPNG( 94 const HSL& upper_bound,
94 scoped_refptr<base::RefCountedMemory> png, 95 KMeanImageSampler* sampler);
95 uint32_t darkness_limit,
96 uint32_t brightness_limit,
97 KMeanImageSampler* sampler);
98 GFX_EXPORT SkColor CalculateKMeanColorOfBitmap(const SkBitmap& bitmap, 96 GFX_EXPORT SkColor CalculateKMeanColorOfBitmap(const SkBitmap& bitmap,
99 uint32_t darkness_limit, 97 const HSL& lower_bound,
100 uint32_t brightness_limit, 98 const HSL& upper_bound,
101 KMeanImageSampler* sampler); 99 KMeanImageSampler* sampler);
102 100
103 // Computes a dominant color using the above algorithm and reasonable defaults 101 // Computes a dominant color for using the above algorithm and reasonable
104 // for |darkness_limit|, |brightness_limit| and |sampler|. 102 // defaults for |lower_bound|, |upper_bound| and |sampler|.
105 GFX_EXPORT SkColor 103 GFX_EXPORT SkColor
106 CalculateKMeanColorOfPNG(scoped_refptr<base::RefCountedMemory> png); 104 CalculateKMeanColorOfPNG(scoped_refptr<base::RefCountedMemory> png);
107 GFX_EXPORT SkColor CalculateKMeanColorOfBitmap(const SkBitmap& bitmap); 105 GFX_EXPORT SkColor CalculateKMeanColorOfBitmap(const SkBitmap& bitmap);
108 106
109 // Compute color covariance matrix for the input bitmap. 107 // Compute color covariance matrix for the input bitmap.
110 GFX_EXPORT gfx::Matrix3F ComputeColorCovariance(const SkBitmap& bitmap); 108 GFX_EXPORT gfx::Matrix3F ComputeColorCovariance(const SkBitmap& bitmap);
111 109
112 // Apply a color reduction transform defined by |color_transform| vector to 110 // Apply a color reduction transform defined by |color_transform| vector to
113 // |source_bitmap|. The result is put into |target_bitmap|, which is expected 111 // |source_bitmap|. The result is put into |target_bitmap|, which is expected
114 // to be initialized to the required size and type (SkBitmap::kA8_Config). 112 // to be initialized to the required size and type (SkBitmap::kA8_Config).
(...skipping 10 matching lines...) Expand all
125 // initialized to the required size and type (SkBitmap::kA8_Config). 123 // initialized to the required size and type (SkBitmap::kA8_Config).
126 // Returns true if the conversion succeeded. Note that there might be legitimate 124 // Returns true if the conversion succeeded. Note that there might be legitimate
127 // reasons for the process to fail even if all input was correct. This is a 125 // reasons for the process to fail even if all input was correct. This is a
128 // condition the caller must be able to handle. 126 // condition the caller must be able to handle.
129 GFX_EXPORT bool ComputePrincipalComponentImage(const SkBitmap& source_bitmap, 127 GFX_EXPORT bool ComputePrincipalComponentImage(const SkBitmap& source_bitmap,
130 SkBitmap* target_bitmap); 128 SkBitmap* target_bitmap);
131 129
132 } // namespace color_utils 130 } // namespace color_utils
133 131
134 #endif // UI_GFX_COLOR_ANALYSIS_H_ 132 #endif // UI_GFX_COLOR_ANALYSIS_H_
OLDNEW

Powered by Google App Engine
This is Rietveld 408576698