text: /*
   * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
   * Copyright (C) 2013 Google Inc. All rights reserved.
   *
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Library General Public
   * License as published by the Free Software Foundation; either
   * version 2 of the License, or (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Library General Public License for more details.
   *
   * You should have received a copy of the GNU Library General Public License
   * along with this library; see the file COPYING.LIB.  If not, write to
   * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   * Boston, MA 02110-1301, USA.
   */
  
  #include "sky/engine/config.h"
  #include "sky/engine/platform/graphics/filters/SourceAlpha.h"
  
  #include "sky/engine/platform/graphics/Color.h"
  #include "sky/engine/platform/graphics/GraphicsContext.h"
  #include "sky/engine/platform/graphics/filters/Filter.h"
  #include "sky/engine/platform/graphics/filters/SkiaImageFilterBuilder.h"
  #include "sky/engine/platform/graphics/filters/SourceGraphic.h"
  #include "sky/engine/platform/text/TextStream.h"
  #include "sky/engine/wtf/StdLibExtras.h"
  #include "sky/engine/wtf/text/WTFString.h"
  #include "third_party/skia/include/effects/SkColorFilterImageFilter.h"
  #include "third_party/skia/include/effects/SkColorMatrixFilter.h"
  
  namespace blink {
  
  PassRefPtr<SourceAlpha> SourceAlpha::create(Filter* filter)
  {
      return adoptRef(new SourceAlpha(filter));
  }
  
  const AtomicString& SourceAlpha::effectName()
  {
      DEFINE_STATIC_LOCAL(const AtomicString, s_effectName, ("SourceAlpha", AtomicString::ConstructFromLiteral));
      return s_effectName;
  }
  
  FloatRect SourceAlpha::determineAbsolutePaintRect(const FloatRect& requestedRect)
  {
      FloatRect srcRect = filter()->sourceImageRect();
      srcRect.intersect(requestedRect);
      addAbsolutePaintRect(srcRect);
      return srcRect;
  }
  
  void SourceAlpha::applySoftware()
  {
      ImageBuffer* resultImage = createImageBufferResult();
      Filter* filter = this->filter();
      if (!resultImage || !filter->sourceImage())
          return;
  
      setIsAlphaImage(true);
  
      FloatRect imageRect(FloatPoint(), absolutePaintRect().size());
      GraphicsContext* filterContext = resultImage->context();
      filterContext->fillRect(imageRect, Color::black);
  
      IntRect srcRect = filter->sourceImageRect();
      if (ImageBuffer* sourceImageBuffer = filter->sourceImage()) {
          filterContext->drawImageBuffer(sourceImageBuffer,
              FloatRect(IntPoint(srcRect.location() - absolutePaintRect().location()), sourceImageBuffer->size()),
              0, CompositeDestinationIn);
      }
  }
  
  PassRefPtr<SkImageFilter> SourceAlpha::createImageFilter(SkiaImageFilterBuilder* builder)
  {
      RefPtr<SkImageFilter> sourceGraphic(builder->build(builder->sourceGraphic(), operatingColorSpace()));
      SkScalar matrix[20] = {
          0, 0, 0, 0, 0,
          0, 0, 0, 0, 0,
          0, 0, 0, 0, 0,
          0, 0, 0, SK_Scalar1, 0
      };
      RefPtr<SkColorFilter> colorFilter(adoptRef(SkColorMatrixFilter::Create(matrix)));
      return adoptRef(SkColorFilterImageFilter::Create(colorFilter.get(), sourceGraphic.get()));
  }
  
  TextStream& SourceAlpha::externalRepresentation(TextStream& ts, int indent) const
  {
      writeIndent(ts, indent);
      ts << "[SourceAlpha]\n";
      return ts;
  }
  
  } // namespace blink
  