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      1 /*
      2  * Copyright (C) 2009 Dirk Schulze <krit (at) webkit.org>
      3  *
      4  * This library is free software; you can redistribute it and/or
      5  * modify it under the terms of the GNU Library General Public
      6  * License as published by the Free Software Foundation; either
      7  * version 2 of the License, or (at your option) any later version.
      8  *
      9  * This library is distributed in the hope that it will be useful,
     10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
     11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     12  * Library General Public License for more details.
     13  *
     14  * You should have received a copy of the GNU Library General Public License
     15  * along with this library; see the file COPYING.LIB.  If not, write to
     16  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     17  * Boston, MA 02110-1301, USA.
     18  */
     19 
     20 #include "config.h"
     21 
     22 #if ENABLE(FILTERS)
     23 #include "SourceAlpha.h"
     24 
     25 #include "Color.h"
     26 #include "Filter.h"
     27 #include "GraphicsContext.h"
     28 #include "PlatformString.h"
     29 #include "RenderTreeAsText.h"
     30 #include "TextStream.h"
     31 
     32 #include <wtf/StdLibExtras.h>
     33 
     34 namespace WebCore {
     35 
     36 PassRefPtr<SourceAlpha> SourceAlpha::create(Filter* filter)
     37 {
     38     return adoptRef(new SourceAlpha(filter));
     39 }
     40 
     41 const AtomicString& SourceAlpha::effectName()
     42 {
     43     DEFINE_STATIC_LOCAL(const AtomicString, s_effectName, ("SourceAlpha"));
     44     return s_effectName;
     45 }
     46 
     47 void SourceAlpha::determineAbsolutePaintRect()
     48 {
     49     Filter* filter = this->filter();
     50     FloatRect paintRect = filter->sourceImageRect();
     51     paintRect.scale(filter->filterResolution().width(), filter->filterResolution().height());
     52     setAbsolutePaintRect(enclosingIntRect(paintRect));
     53 }
     54 
     55 void SourceAlpha::apply()
     56 {
     57     if (hasResult())
     58         return;
     59     ImageBuffer* resultImage = createImageBufferResult();
     60     Filter* filter = this->filter();
     61     if (!resultImage || !filter->sourceImage())
     62         return;
     63 
     64     setIsAlphaImage(true);
     65 
     66     FloatRect imageRect(FloatPoint(), absolutePaintRect().size());
     67     GraphicsContext* filterContext = resultImage->context();
     68     filterContext->save();
     69     filterContext->clipToImageBuffer(filter->sourceImage(), imageRect);
     70     filterContext->fillRect(imageRect, Color::black, ColorSpaceDeviceRGB);
     71     filterContext->restore();
     72 }
     73 
     74 void SourceAlpha::dump()
     75 {
     76 }
     77 
     78 TextStream& SourceAlpha::externalRepresentation(TextStream& ts, int indent) const
     79 {
     80     writeIndent(ts, indent);
     81     ts << "[SourceAlpha]\n";
     82     return ts;
     83 }
     84 
     85 } // namespace WebCore
     86 
     87 #endif // ENABLE(FILTERS)
     88