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1 // Copyright (c) 2010 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2010 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 APP_GFX_COLOR_UTILS_H_ | 5 #ifndef APP_GFX_COLOR_UTILS_H_ |
6 #define APP_GFX_COLOR_UTILS_H_ | 6 #define APP_GFX_COLOR_UTILS_H_ |
7 #pragma once | 7 #pragma once |
8 | 8 |
9 #include "third_party/skia/include/core/SkColor.h" | 9 #include "ui/gfx/color_utils.h" |
10 | 10 // TODO(sail): remove this file once all includes have been updated. |
11 class SkBitmap; | |
12 | |
13 namespace color_utils { | |
14 | |
15 // Represents an HSL color. | |
16 struct HSL { | |
17 double h; | |
18 double s; | |
19 double l; | |
20 }; | |
21 | |
22 // Calculated according to http://www.w3.org/TR/WCAG20/#relativeluminancedef | |
23 double RelativeLuminance(SkColor color); | |
24 | |
25 // Note: these transformations assume sRGB as the source color space | |
26 void SkColorToHSL(SkColor c, HSL* hsl); | |
27 SkColor HSLToSkColor(const HSL& hsl, SkAlpha alpha); | |
28 | |
29 // HSL-Shift an SkColor. The shift values are in the range of 0-1, with the | |
30 // option to specify -1 for 'no change'. The shift values are defined as: | |
31 // hsl_shift[0] (hue): The absolute hue value - 0 and 1 map | |
32 // to 0 and 360 on the hue color wheel (red). | |
33 // hsl_shift[1] (saturation): A saturation shift, with the | |
34 // following key values: | |
35 // 0 = remove all color. | |
36 // 0.5 = leave unchanged. | |
37 // 1 = fully saturate the image. | |
38 // hsl_shift[2] (lightness): A lightness shift, with the | |
39 // following key values: | |
40 // 0 = remove all lightness (make all pixels black). | |
41 // 0.5 = leave unchanged. | |
42 // 1 = full lightness (make all pixels white). | |
43 SkColor HSLShift(SkColor color, const HSL& shift); | |
44 | |
45 // Determine if a given alpha value is nearly completely transparent. | |
46 bool IsColorCloseToTransparent(SkAlpha alpha); | |
47 | |
48 // Determine if a color is near grey. | |
49 bool IsColorCloseToGrey(int r, int g, int b); | |
50 | |
51 // Gets a color representing a bitmap. The definition of "representing" is the | |
52 // average color in the bitmap. The color returned is modified to have the | |
53 // specified alpha. | |
54 SkColor GetAverageColorOfFavicon(SkBitmap* bitmap, SkAlpha alpha); | |
55 | |
56 // Builds a histogram based on the Y' of the Y'UV representation of | |
57 // this image. | |
58 void BuildLumaHistogram(SkBitmap* bitmap, int histogram[256]); | |
59 | |
60 // Returns a blend of the supplied colors, ranging from |background| (for | |
61 // |alpha| == 0) to |foreground| (for |alpha| == 255). The alpha channels of | |
62 // the supplied colors are also taken into account, so the returned color may | |
63 // be partially transparent. | |
64 SkColor AlphaBlend(SkColor foreground, SkColor background, SkAlpha alpha); | |
65 | |
66 // Given a foreground and background color, try to return a foreground color | |
67 // that is "readable" over the background color by luma-inverting the foreground | |
68 // color and then picking whichever foreground color has higher contrast against | |
69 // the background color. | |
70 // | |
71 // NOTE: This won't do anything but waste time if the supplied foreground color | |
72 // has a luma value close to the midpoint (0.5 in the HSL representation). | |
73 SkColor GetReadableColor(SkColor foreground, SkColor background); | |
74 | |
75 // Gets a Windows system color as a SkColor | |
76 SkColor GetSysSkColor(int which); | |
77 | |
78 } // namespace color_utils | |
79 | 11 |
80 #endif // APP_GFX_COLOR_UTILS_H_ | 12 #endif // APP_GFX_COLOR_UTILS_H_ |
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