1/*
2 * Copyright (C) Research In Motion Limited 2011. All rights reserved.
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 "FEDropShadow.h"
24
25#include "ColorSpace.h"
26#include "FEGaussianBlur.h"
27#include "Filter.h"
28#include "GraphicsContext.h"
29#include "RenderTreeAsText.h"
30#include "ShadowBlur.h"
31#include "TextStream.h"
32#include <wtf/MathExtras.h>
33#include <wtf/Uint8ClampedArray.h>
34
35using namespace std;
36
37namespace WebCore {
38
39FEDropShadow::FEDropShadow(Filter* filter, float stdX, float stdY, float dx, float dy, const Color& shadowColor, float shadowOpacity)
40    : FilterEffect(filter)
41    , m_stdX(stdX)
42    , m_stdY(stdY)
43    , m_dx(dx)
44    , m_dy(dy)
45    , m_shadowColor(shadowColor)
46    , m_shadowOpacity(shadowOpacity)
47{
48}
49
50PassRefPtr<FEDropShadow> FEDropShadow::create(Filter* filter, float stdX, float stdY, float dx, float dy, const Color& shadowColor, float shadowOpacity)
51{
52    return adoptRef(new FEDropShadow(filter, stdX, stdY, dx, dy, shadowColor, shadowOpacity));
53}
54
55void FEDropShadow::determineAbsolutePaintRect()
56{
57    Filter* filter = this->filter();
58    ASSERT(filter);
59
60    FloatRect absolutePaintRect = inputEffect(0)->absolutePaintRect();
61    FloatRect absoluteOffsetPaintRect(absolutePaintRect);
62    absoluteOffsetPaintRect.move(filter->applyHorizontalScale(m_dx), filter->applyVerticalScale(m_dy));
63    absolutePaintRect.unite(absoluteOffsetPaintRect);
64
65    unsigned kernelSizeX = 0;
66    unsigned kernelSizeY = 0;
67    FEGaussianBlur::calculateKernelSize(filter, kernelSizeX, kernelSizeY, m_stdX, m_stdY);
68
69    // We take the half kernel size and multiply it with three, because we run box blur three times.
70    absolutePaintRect.inflateX(3 * kernelSizeX * 0.5f);
71    absolutePaintRect.inflateY(3 * kernelSizeY * 0.5f);
72
73    if (clipsToBounds())
74        absolutePaintRect.intersect(maxEffectRect());
75    else
76        absolutePaintRect.unite(maxEffectRect());
77
78    setAbsolutePaintRect(enclosingIntRect(absolutePaintRect));
79}
80
81void FEDropShadow::platformApplySoftware()
82{
83    FilterEffect* in = inputEffect(0);
84
85    ImageBuffer* resultImage = createImageBufferResult();
86    if (!resultImage)
87        return;
88
89    Filter* filter = this->filter();
90    FloatSize blurRadius(filter->applyHorizontalScale(m_stdX), filter->applyVerticalScale(m_stdY));
91    FloatSize offset(filter->applyHorizontalScale(m_dx), filter->applyVerticalScale(m_dy));
92
93    FloatRect drawingRegion = drawingRegionOfInputImage(in->absolutePaintRect());
94    FloatRect drawingRegionWithOffset(drawingRegion);
95    drawingRegionWithOffset.move(offset);
96
97    ImageBuffer* sourceImage = in->asImageBuffer();
98    ASSERT(sourceImage);
99    GraphicsContext* resultContext = resultImage->context();
100    ASSERT(resultContext);
101    resultContext->setAlpha(m_shadowOpacity);
102    resultContext->drawImageBuffer(sourceImage, ColorSpaceDeviceRGB, drawingRegionWithOffset);
103    resultContext->setAlpha(1);
104
105    ShadowBlur contextShadow(blurRadius, offset, m_shadowColor, ColorSpaceDeviceRGB);
106
107    // TODO: Direct pixel access to ImageBuffer would avoid copying the ImageData.
108    IntRect shadowArea(IntPoint(), resultImage->internalSize());
109    RefPtr<Uint8ClampedArray> srcPixelArray = resultImage->getPremultipliedImageData(shadowArea);
110
111    contextShadow.blurLayerImage(srcPixelArray->data(), shadowArea.size(), 4 * shadowArea.size().width());
112
113    resultImage->putByteArray(Premultiplied, srcPixelArray.get(), shadowArea.size(), shadowArea, IntPoint());
114
115    resultContext->setCompositeOperation(CompositeSourceIn);
116    resultContext->fillRect(FloatRect(FloatPoint(), absolutePaintRect().size()), m_shadowColor, ColorSpaceDeviceRGB);
117    resultContext->setCompositeOperation(CompositeDestinationOver);
118
119    resultImage->context()->drawImageBuffer(sourceImage, ColorSpaceDeviceRGB, drawingRegion);
120}
121
122void FEDropShadow::dump()
123{
124}
125
126TextStream& FEDropShadow::externalRepresentation(TextStream& ts, int indent) const
127{
128    writeIndent(ts, indent);
129    ts << "[feDropShadow";
130    FilterEffect::externalRepresentation(ts);
131    ts << " stdDeviation=\"" << m_stdX << ", " << m_stdY << "\" dx=\"" << m_dx << "\" dy=\"" << m_dy << "\" flood-color=\"" << m_shadowColor.nameForRenderTreeAsText() <<"\" flood-opacity=\"" << m_shadowOpacity << "]\n";
132    inputEffect(0)->externalRepresentation(ts, indent + 1);
133    return ts;
134}
135
136} // namespace WebCore
137
138#endif // ENABLE(FILTERS)
139