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1 /*
2  * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
3  * Copyright (C) 2013 Google Inc. All rights reserved.
4  *
5  * This library is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Library General Public
7  * License as published by the Free Software Foundation; either
8  * version 2 of the License, or (at your option) any later version.
9  *
10  * This library is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  * Library General Public License for more details.
14  *
15  * You should have received a copy of the GNU Library General Public License
16  * along with this library; see the file COPYING.LIB.  If not, write to
17  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
18  * Boston, MA 02110-1301, USA.
19  */
20 
21 #include "config.h"
22 #include "platform/graphics/filters/SourceAlpha.h"
23 
24 #include "platform/graphics/Color.h"
25 #include "platform/graphics/GraphicsContext.h"
26 #include "platform/graphics/filters/Filter.h"
27 #include "platform/graphics/filters/SkiaImageFilterBuilder.h"
28 #include "platform/graphics/filters/SourceGraphic.h"
29 #include "platform/text/TextStream.h"
30 #include "third_party/skia/include/effects/SkColorFilterImageFilter.h"
31 #include "third_party/skia/include/effects/SkColorMatrixFilter.h"
32 #include "wtf/StdLibExtras.h"
33 #include "wtf/text/WTFString.h"
34 
35 namespace blink {
36 
create(Filter * filter)37 PassRefPtr<SourceAlpha> SourceAlpha::create(Filter* filter)
38 {
39     return adoptRef(new SourceAlpha(filter));
40 }
41 
effectName()42 const AtomicString& SourceAlpha::effectName()
43 {
44     DEFINE_STATIC_LOCAL(const AtomicString, s_effectName, ("SourceAlpha", AtomicString::ConstructFromLiteral));
45     return s_effectName;
46 }
47 
determineAbsolutePaintRect(const FloatRect & requestedRect)48 FloatRect SourceAlpha::determineAbsolutePaintRect(const FloatRect& requestedRect)
49 {
50     FloatRect srcRect = filter()->sourceImageRect();
51     srcRect.intersect(requestedRect);
52     addAbsolutePaintRect(srcRect);
53     return srcRect;
54 }
55 
applySoftware()56 void SourceAlpha::applySoftware()
57 {
58     ImageBuffer* resultImage = createImageBufferResult();
59     Filter* filter = this->filter();
60     if (!resultImage || !filter->sourceImage())
61         return;
62 
63     setIsAlphaImage(true);
64 
65     FloatRect imageRect(FloatPoint(), absolutePaintRect().size());
66     GraphicsContext* filterContext = resultImage->context();
67     filterContext->fillRect(imageRect, Color::black);
68 
69     IntRect srcRect = filter->sourceImageRect();
70     if (ImageBuffer* sourceImageBuffer = filter->sourceImage()) {
71         filterContext->drawImageBuffer(sourceImageBuffer,
72             FloatRect(IntPoint(srcRect.location() - absolutePaintRect().location()), sourceImageBuffer->size()),
73             0, CompositeDestinationIn);
74     }
75 }
76 
createImageFilter(SkiaImageFilterBuilder * builder)77 PassRefPtr<SkImageFilter> SourceAlpha::createImageFilter(SkiaImageFilterBuilder* builder)
78 {
79     RefPtr<SkImageFilter> sourceGraphic(builder->build(builder->sourceGraphic(), operatingColorSpace()));
80     SkScalar matrix[20] = {
81         0, 0, 0, 0, 0,
82         0, 0, 0, 0, 0,
83         0, 0, 0, 0, 0,
84         0, 0, 0, SK_Scalar1, 0
85     };
86     RefPtr<SkColorFilter> colorFilter(adoptRef(SkColorMatrixFilter::Create(matrix)));
87     return adoptRef(SkColorFilterImageFilter::Create(colorFilter.get(), sourceGraphic.get()));
88 }
89 
externalRepresentation(TextStream & ts,int indent) const90 TextStream& SourceAlpha::externalRepresentation(TextStream& ts, int indent) const
91 {
92     writeIndent(ts, indent);
93     ts << "[SourceAlpha]\n";
94     return ts;
95 }
96 
97 } // namespace blink
98