src/third_party/WebKit/Source/platform/graphics/filters/FEDropShadow.cpp

   1 /*
   2  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
   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 #include "platform/graphics/filters/FEDropShadow.h"
  23
  24 #include "platform/graphics/GraphicsContext.h"
  25 #include "platform/graphics/filters/FEGaussianBlur.h"
  26 #include "platform/graphics/filters/SkiaImageFilterBuilder.h"
  27 #include "platform/text/TextStream.h"
  28 #include "third_party/skia/include/core/SkColorFilter.h"
  29 #include "third_party/skia/include/effects/SkBlurImageFilter.h"
  30 #include "third_party/skia/include/effects/SkDropShadowImageFilter.h"
  31
  32 using namespace std;
  33
  34 namespace WebCore {
  35
  36 FEDropShadow::FEDropShadow(Filter* filter, float stdX, float stdY, float dx, float dy, const Color& shadowColor, float shadowOpacity)
  37     : FilterEffect(filter)
  38     , m_stdX(stdX)
  39     , m_stdY(stdY)
  40     , m_dx(dx)
  41     , m_dy(dy)
  42     , m_shadowColor(shadowColor)
  43     , m_shadowOpacity(shadowOpacity)
  44 {
  45 }
  46
  47 PassRefPtr<FEDropShadow> FEDropShadow::create(Filter* filter, float stdX, float stdY, float dx, float dy, const Color& shadowColor, float shadowOpacity)
  48 {
  49     return adoptRef(new FEDropShadow(filter, stdX, stdY, dx, dy, shadowColor, shadowOpacity));
  50 }
  51
  52 FloatRect FEDropShadow::mapRect(const FloatRect& rect, bool forward)
  53 {
  54     FloatRect result = rect;
  55     Filter* filter = this->filter();
  56     ASSERT(filter);
  57
  58     FloatRect offsetRect = rect;
  59     if (forward)
  60         offsetRect.move(filter->applyHorizontalScale(m_dx), filter->applyVerticalScale(m_dy));
  61     else
  62         offsetRect.move(-filter->applyHorizontalScale(m_dx), -filter->applyVerticalScale(m_dy));
  63     result.unite(offsetRect);
  64
  65     IntSize kernelSize = FEGaussianBlur::calculateKernelSize(filter, FloatPoint(m_stdX, m_stdY));
  66
  67     // We take the half kernel size and multiply it with three, because we run box blur three times.
  68     result.inflateX(3 * kernelSize.width() * 0.5f);
  69     result.inflateY(3 * kernelSize.height() * 0.5f);
  70     return result;
  71 }
  72
  73 void FEDropShadow::applySoftware()
  74 {
  75     FilterEffect* in = inputEffect(0);
  76
  77     ImageBuffer* resultImage = createImageBufferResult();
  78     if (!resultImage)
  79         return;
  80
  81     Filter* filter = this->filter();
  82     FloatSize blurRadius(filter->applyHorizontalScale(m_stdX), filter->applyVerticalScale(m_stdY));
  83     FloatSize offset(filter->applyHorizontalScale(m_dx), filter->applyVerticalScale(m_dy));
  84
  85     FloatRect drawingRegion = drawingRegionOfInputImage(in->absolutePaintRect());
  86     GraphicsContext* resultContext = resultImage->context();
  87     ASSERT(resultContext);
  88
  89     Color color = adaptColorToOperatingColorSpace(m_shadowColor.combineWithAlpha(m_shadowOpacity));
  90     SkAutoTUnref<SkImageFilter> blurFilter(SkBlurImageFilter::Create(blurRadius.width(), blurRadius.height()));
  91     SkAutoTUnref<SkColorFilter> colorFilter(SkColorFilter::CreateModeFilter(color.rgb(), SkXfermode::kSrcIn_Mode));
  92     SkPaint paint;
  93     paint.setImageFilter(blurFilter.get());
  94     paint.setColorFilter(colorFilter.get());
  95     paint.setXfermodeMode(SkXfermode::kSrcOver_Mode);
  96     RefPtr<Image> image = in->asImageBuffer()->copyImage(DontCopyBackingStore);
  97
  98     RefPtr<NativeImageSkia> nativeImage = image->nativeImageForCurrentFrame();
  99
 100     if (!nativeImage)
 101         return;
 102
 103     resultContext->drawBitmap(nativeImage->bitmap(), drawingRegion.x() + offset.width(), drawingRegion.y() + offset.height(), &paint);
 104     resultContext->drawBitmap(nativeImage->bitmap(), drawingRegion.x(), drawingRegion.y());
 105 }
 106
 107 PassRefPtr<SkImageFilter> FEDropShadow::createImageFilter(SkiaImageFilterBuilder* builder)
 108 {
 109     RefPtr<SkImageFilter> input(builder->build(inputEffect(0), operatingColorSpace()));
 110     float dx = filter()->applyHorizontalScale(m_dx);
 111     float dy = filter()->applyVerticalScale(m_dy);
 112     float stdX = filter()->applyHorizontalScale(m_stdX);
 113     float stdY = filter()->applyVerticalScale(m_stdY);
 114     Color color = adaptColorToOperatingColorSpace(m_shadowColor.combineWithAlpha(m_shadowOpacity));
 115     SkImageFilter::CropRect cropRect = getCropRect(builder->cropOffset());
 116     return adoptRef(SkDropShadowImageFilter::Create(SkFloatToScalar(dx), SkFloatToScalar(dy), SkFloatToScalar(stdX), SkFloatToScalar(stdY), color.rgb(), input.get(), &cropRect));
 117 }
 118
 119
 120 TextStream& FEDropShadow::externalRepresentation(TextStream& ts, int indent) const
 121 {
 122     writeIndent(ts, indent);
 123     ts << "[feDropShadow";
 124     FilterEffect::externalRepresentation(ts);
 125     ts << " stdDeviation=\"" << m_stdX << ", " << m_stdY << "\" dx=\"" << m_dx << "\" dy=\"" << m_dy << "\" flood-color=\"" << m_shadowColor.nameForRenderTreeAsText() <<"\" flood-opacity=\"" << m_shadowOpacity << "]\n";
 126     inputEffect(0)->externalRepresentation(ts, indent + 1);
 127     return ts;
 128 }
 129
 130 } // namespace WebCore