text: /*
      Copyright (C) 2004, 2005, 2006, 2007 Nikolas Zimmermann <zimmermann@kde.org>
                    2004, 2005 Rob Buis <buis@kde.org>
                    2005 Eric Seidel <eric@webkit.org>
                    2009 Dirk Schulze <krit@webkit.org>
  
      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
      aint 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 "config.h"
  
  #if ENABLE(SVG) && ENABLE(FILTERS)
  #include "SVGFEDisplacementMap.h"
  
  #include "CanvasPixelArray.h"
  #include "Filter.h"
  #include "GraphicsContext.h"
  #include "ImageData.h"
  #include "SVGRenderTreeAsText.h"
  
  namespace WebCore {
  
  FEDisplacementMap::FEDisplacementMap(FilterEffect* in, FilterEffect* in2, ChannelSelectorType xChannelSelector,
      ChannelSelectorType yChannelSelector, const float& scale)
      : FilterEffect()
      , m_in(in)
      , m_in2(in2)
      , m_xChannelSelector(xChannelSelector)
      , m_yChannelSelector(yChannelSelector)
      , m_scale(scale)
  {
  }
  
  PassRefPtr<FEDisplacementMap> FEDisplacementMap::create(FilterEffect* in, FilterEffect* in2,
      ChannelSelectorType xChannelSelector, ChannelSelectorType yChannelSelector, const float& scale)
  {
      return adoptRef(new FEDisplacementMap(in, in2, xChannelSelector, yChannelSelector, scale));
  }
  
  ChannelSelectorType FEDisplacementMap::xChannelSelector() const
  {
      return m_xChannelSelector;
  }
  
  void FEDisplacementMap::setXChannelSelector(const ChannelSelectorType xChannelSelector)
  {
      m_xChannelSelector = xChannelSelector;
  }
  
  ChannelSelectorType FEDisplacementMap::yChannelSelector() const
  {
      return m_yChannelSelector;
  }
  
  void FEDisplacementMap::setYChannelSelector(const ChannelSelectorType yChannelSelector)
  {
      m_yChannelSelector = yChannelSelector;
  }
  
  float FEDisplacementMap::scale() const
  {
      return m_scale;
  }
  
  void FEDisplacementMap::setScale(float scale)
  {
      m_scale = scale;
  }
  
  void FEDisplacementMap::apply(Filter* filter)
  {
      m_in->apply(filter);
      m_in2->apply(filter);
      if (!m_in->resultImage() || !m_in2->resultImage())
          return;
  
      if (m_xChannelSelector == CHANNEL_UNKNOWN || m_yChannelSelector == CHANNEL_UNKNOWN)
          return;
  
      if (!getEffectContext())
          return;
  
      IntRect effectADrawingRect = calculateDrawingIntRect(m_in->scaledSubRegion());
      RefPtr<CanvasPixelArray> srcPixelArrayA(m_in->resultImage()->getPremultipliedImageData(effectADrawingRect)->data());
  
      IntRect effectBDrawingRect = calculateDrawingIntRect(m_in2->scaledSubRegion());
      RefPtr<CanvasPixelArray> srcPixelArrayB(m_in2->resultImage()->getUnmultipliedImageData(effectBDrawingRect)->data());
  
      IntRect imageRect(IntPoint(), resultImage()->size());
      RefPtr<ImageData> imageData = ImageData::create(imageRect.width(), imageRect.height());
  
      ASSERT(srcPixelArrayA->length() == srcPixelArrayB->length());
  
      float scaleX = m_scale / 255.f * filter->filterResolution().width();
      float scaleY = m_scale / 255.f * filter->filterResolution().height();
      float scaleAdjustmentX = (0.5f - 0.5f * m_scale) * filter->filterResolution().width();
      float scaleAdjustmentY = (0.5f - 0.5f * m_scale) * filter->filterResolution().height();
      int stride = imageRect.width() * 4;
      for (int y = 0; y < imageRect.height(); ++y) {
          int line = y * stride;
          for (int x = 0; x < imageRect.width(); ++x) {
              int dstIndex = line + x * 4;
              int srcX = x + static_cast<int>(scaleX * srcPixelArrayB->get(dstIndex + m_xChannelSelector - 1) + scaleAdjustmentX);
              int srcY = y + static_cast<int>(scaleY * srcPixelArrayB->get(dstIndex + m_yChannelSelector - 1) + scaleAdjustmentY);
              for (unsigned channel = 0; channel < 4; ++channel) {
                  if (srcX < 0 || srcX >= imageRect.width() || srcY < 0 || srcY >= imageRect.height())
                      imageData->data()->set(dstIndex + channel, static_cast<unsigned char>(0));
                  else {
                      unsigned char pixelValue = srcPixelArrayA->get(srcY * stride + srcX * 4 + channel);
                      imageData->data()->set(dstIndex + channel, pixelValue);
                  }
              }
  
          }
      }
      resultImage()->putPremultipliedImageData(imageData.get(), imageRect, IntPoint());
  }
  
  void FEDisplacementMap::dump()
  {
  }
  
  static TextStream& operator<<(TextStream& ts, const ChannelSelectorType& type)
  {
      switch (type) {
      case CHANNEL_UNKNOWN:
          ts << "UNKNOWN";
          break;
      case CHANNEL_R:
          ts << "RED";
          break;
      case CHANNEL_G:
          ts << "GREEN";
          break;
      case CHANNEL_B:
          ts << "BLUE";
          break;
      case CHANNEL_A:
          ts << "ALPHA";
          break;
      }
      return ts;
  }
  
  TextStream& FEDisplacementMap::externalRepresentation(TextStream& ts, int indent) const
  {
      writeIndent(ts, indent);
      ts << "[feDisplacementMap";
      FilterEffect::externalRepresentation(ts);
      ts << " scale=\"" << m_scale << "\" "
         << "xChannelSelector=\"" << m_xChannelSelector << "\" "
         << "yChannelSelector=\"" << m_yChannelSelector << "\"]\n";
      m_in->externalRepresentation(ts, indent + 1);
      m_in2->externalRepresentation(ts, indent + 1);
      return ts;
  }
  
  } // namespace WebCore
  
  #endif // ENABLE(SVG) && ENABLE(FILTERS)
  