1 /*
2  * Copyright (C) 2003, 2004, 2005, 2006, 2010 Apple Inc. All rights reserved.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  */
25 
26 #ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_GRAPHICS_COLOR_BLEND_H_
27 #define THIRD_PARTY_BLINK_RENDERER_PLATFORM_GRAPHICS_COLOR_BLEND_H_
28 
29 #include "third_party/blink/renderer/platform/geometry/blend.h"
30 #include "third_party/blink/renderer/platform/graphics/color.h"
31 
32 namespace blink {
33 
34 inline Color Blend(const Color& from,
35                    const Color& to,
36                    double progress,
37                    bool blend_premultiplied = true) {
38   if (blend_premultiplied) {
39     // Contrary to the name, RGBA32 actually stores ARGB, so we can initialize
40     // Color directly from premultipliedARGBFromColor(). Also,
41     // premultipliedARGBFromColor() bails on zero alpha, so special-case that.
42     Color premult_from = from.Alpha() ? PremultipliedARGBFromColor(from) : 0;
43     Color premult_to = to.Alpha() ? PremultipliedARGBFromColor(to) : 0;
44 
45     Color premult_blended(
46         Blend(premult_from.Red(), premult_to.Red(), progress),
47         Blend(premult_from.Green(), premult_to.Green(), progress),
48         Blend(premult_from.Blue(), premult_to.Blue(), progress),
49         Blend(premult_from.Alpha(), premult_to.Alpha(), progress));
50 
51     return Color(ColorFromPremultipliedARGB(premult_blended.Rgb()));
52   }
53 
54   return Color(Blend(from.Red(), to.Red(), progress),
55                Blend(from.Green(), to.Green(), progress),
56                Blend(from.Blue(), to.Blue(), progress),
57                Blend(from.Alpha(), to.Alpha(), progress));
58 }
59 
60 }  // namespace blink
61 
62 #endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_GRAPHICS_COLOR_BLEND_H_
63