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