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      1 /*
      2  * Copyright (C) 2009 Dirk Schulze <krit (at) 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 
     23 #include "core/platform/graphics/filters/SourceAlpha.h"
     24 
     25 #include "core/platform/graphics/Color.h"
     26 #include "core/platform/graphics/GraphicsContext.h"
     27 #include "core/platform/graphics/filters/Filter.h"
     28 #include "core/platform/text/TextStream.h"
     29 #include "core/rendering/RenderTreeAsText.h"
     30 #include "wtf/StdLibExtras.h"
     31 #include "wtf/text/WTFString.h"
     32 
     33 namespace WebCore {
     34 
     35 PassRefPtr<SourceAlpha> SourceAlpha::create(Filter* filter)
     36 {
     37     return adoptRef(new SourceAlpha(filter));
     38 }
     39 
     40 const AtomicString& SourceAlpha::effectName()
     41 {
     42     DEFINE_STATIC_LOCAL(const AtomicString, s_effectName, ("SourceAlpha", AtomicString::ConstructFromLiteral));
     43     return s_effectName;
     44 }
     45 
     46 void SourceAlpha::determineAbsolutePaintRect()
     47 {
     48     Filter* filter = this->filter();
     49     FloatRect paintRect = filter->sourceImageRect();
     50     paintRect.scale(filter->filterResolution().width(), filter->filterResolution().height());
     51     setAbsolutePaintRect(enclosingIntRect(paintRect));
     52 }
     53 
     54 void SourceAlpha::applySoftware()
     55 {
     56     ImageBuffer* resultImage = createImageBufferResult();
     57     Filter* filter = this->filter();
     58     if (!resultImage || !filter->sourceImage())
     59         return;
     60 
     61     setIsAlphaImage(true);
     62 
     63     FloatRect imageRect(FloatPoint(), absolutePaintRect().size());
     64     GraphicsContext* filterContext = resultImage->context();
     65     filterContext->fillRect(imageRect, Color::black);
     66     filterContext->drawImageBuffer(filter->sourceImage(), IntPoint(), CompositeDestinationIn);
     67 }
     68 
     69 TextStream& SourceAlpha::externalRepresentation(TextStream& ts, int indent) const
     70 {
     71     writeIndent(ts, indent);
     72     ts << "[SourceAlpha]\n";
     73     return ts;
     74 }
     75 
     76 } // namespace WebCore
     77