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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  *  aint 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 "GraphicsContext.h"
     27 #include "PlatformString.h"
     28 #include "Filter.h"
     29 
     30 #include <wtf/StdLibExtras.h>
     31 
     32 namespace WebCore {
     33 
     34 PassRefPtr<SourceAlpha> SourceAlpha::create()
     35 {
     36     return adoptRef(new SourceAlpha);
     37 }
     38 
     39 const AtomicString& SourceAlpha::effectName()
     40 {
     41     DEFINE_STATIC_LOCAL(const AtomicString, s_effectName, ("SourceAlpha"));
     42     return s_effectName;
     43 }
     44 
     45 FloatRect SourceAlpha::calculateEffectRect(Filter* filter)
     46 {
     47     FloatRect clippedSourceRect = filter->sourceImageRect();
     48     if (filter->sourceImageRect().x() < filter->filterRegion().x())
     49         clippedSourceRect.setX(filter->filterRegion().x());
     50     if (filter->sourceImageRect().y() < filter->filterRegion().y())
     51         clippedSourceRect.setY(filter->filterRegion().y());
     52     setSubRegion(clippedSourceRect);
     53     clippedSourceRect.scale(filter->filterResolution().width(), filter->filterResolution().height());
     54     setScaledSubRegion(clippedSourceRect);
     55     return filter->filterRegion();
     56 }
     57 
     58 void SourceAlpha::apply(Filter* filter)
     59 {
     60     GraphicsContext* filterContext = getEffectContext();
     61     if (!filterContext)
     62         return;
     63 
     64     setIsAlphaImage(true);
     65 
     66     FloatRect imageRect(FloatPoint(), filter->sourceImage()->image()->size());
     67     filterContext->save();
     68     filterContext->clipToImageBuffer(imageRect, filter->sourceImage());
     69     filterContext->fillRect(imageRect, Color::black, DeviceColorSpace);
     70     filterContext->restore();
     71 }
     72 
     73 void SourceAlpha::dump()
     74 {
     75 }
     76 
     77 } // namespace WebCore
     78 
     79 #endif // ENABLE(FILTERS)
     80