FEDisplacementMap.cpp revision 65f03d4f644ce73618e5f4f50dd694b26f55ae12 
1/*
2 * Copyright (C) 2004, 2005, 2006, 2007 Nikolas Zimmermann <zimmermann@kde.org>
3 * Copyright (C) 2004, 2005 Rob Buis <buis@kde.org>
4 * Copyright (C) 2005 Eric Seidel <eric@webkit.org>
5 * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
6 * Copyright (C) Research In Motion Limited 2010. All rights reserved.
7 *
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Library General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
12 *
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16 * Library General Public License for more details.
17 *
18 * You should have received a copy of the GNU Library General Public License
19 * along with this library; see the file COPYING.LIB.  If not, write to
20 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
21 * Boston, MA 02110-1301, USA.
22 */
23
24#include "config.h"
25
26#if ENABLE(FILTERS)
27#include "FEDisplacementMap.h"
28
29#include "Filter.h"
30#include "GraphicsContext.h"
31#include "RenderTreeAsText.h"
32#include "TextStream.h"
33
34#include <wtf/ByteArray.h>
35
36namespace WebCore {
37
38FEDisplacementMap::FEDisplacementMap(Filter* filter, ChannelSelectorType xChannelSelector, ChannelSelectorType yChannelSelector, float scale)
39    : FilterEffect(filter)
40    , m_xChannelSelector(xChannelSelector)
41    , m_yChannelSelector(yChannelSelector)
42    , m_scale(scale)
43{
44}
45
46PassRefPtr<FEDisplacementMap> FEDisplacementMap::create(Filter* filter, ChannelSelectorType xChannelSelector,
47    ChannelSelectorType yChannelSelector, float scale)
48{
49    return adoptRef(new FEDisplacementMap(filter, xChannelSelector, yChannelSelector, scale));
50}
51
52ChannelSelectorType FEDisplacementMap::xChannelSelector() const
53{
54    return m_xChannelSelector;
55}
56
57void FEDisplacementMap::setXChannelSelector(const ChannelSelectorType xChannelSelector)
58{
59    m_xChannelSelector = xChannelSelector;
60}
61
62ChannelSelectorType FEDisplacementMap::yChannelSelector() const
63{
64    return m_yChannelSelector;
65}
66
67void FEDisplacementMap::setYChannelSelector(const ChannelSelectorType yChannelSelector)
68{
69    m_yChannelSelector = yChannelSelector;
70}
71
72float FEDisplacementMap::scale() const
73{
74    return m_scale;
75}
76
77void FEDisplacementMap::setScale(float scale)
78{
79    m_scale = scale;
80}
81
82void FEDisplacementMap::apply()
83{
84    if (hasResult())
85        return;
86    FilterEffect* in = inputEffect(0);
87    FilterEffect* in2 = inputEffect(1);
88    in->apply();
89    in2->apply();
90    if (!in->hasResult() || !in2->hasResult())
91        return;
92
93    if (m_xChannelSelector == CHANNEL_UNKNOWN || m_yChannelSelector == CHANNEL_UNKNOWN)
94        return;
95
96    ByteArray* dstPixelArray = createPremultipliedImageResult();
97    if (!dstPixelArray)
98        return;
99
100    IntRect effectADrawingRect = requestedRegionOfInputImageData(in->absolutePaintRect());
101    RefPtr<ByteArray> srcPixelArrayA = in->asPremultipliedImage(effectADrawingRect);
102
103    IntRect effectBDrawingRect = requestedRegionOfInputImageData(in2->absolutePaintRect());
104    RefPtr<ByteArray> srcPixelArrayB = in2->asUnmultipliedImage(effectBDrawingRect);
105
106    ASSERT(srcPixelArrayA->length() == srcPixelArrayB->length());
107
108    Filter* filter = this->filter();
109    IntSize paintSize = absolutePaintRect().size();
110    float scaleX = filter->applyHorizontalScale(m_scale / 255);
111    float scaleY = filter->applyVerticalScale(m_scale / 255);
112    float scaleAdjustmentX = filter->applyHorizontalScale(0.5f - 0.5f * m_scale);
113    float scaleAdjustmentY = filter->applyVerticalScale(0.5f - 0.5f * m_scale);
114    int stride = paintSize.width() * 4;
115    for (int y = 0; y < paintSize.height(); ++y) {
116        int line = y * stride;
117        for (int x = 0; x < paintSize.width(); ++x) {
118            int dstIndex = line + x * 4;
119            int srcX = x + static_cast<int>(scaleX * srcPixelArrayB->get(dstIndex + m_xChannelSelector - 1) + scaleAdjustmentX);
120            int srcY = y + static_cast<int>(scaleY * srcPixelArrayB->get(dstIndex + m_yChannelSelector - 1) + scaleAdjustmentY);
121            for (unsigned channel = 0; channel < 4; ++channel) {
122                if (srcX < 0 || srcX >= paintSize.width() || srcY < 0 || srcY >= paintSize.height())
123                    dstPixelArray->set(dstIndex + channel, static_cast<unsigned char>(0));
124                else {
125                    unsigned char pixelValue = srcPixelArrayA->get(srcY * stride + srcX * 4 + channel);
126                    dstPixelArray->set(dstIndex + channel, pixelValue);
127                }
128            }
129        }
130    }
131}
132
133void FEDisplacementMap::dump()
134{
135}
136
137static TextStream& operator<<(TextStream& ts, const ChannelSelectorType& type)
138{
139    switch (type) {
140    case CHANNEL_UNKNOWN:
141        ts << "UNKNOWN";
142        break;
143    case CHANNEL_R:
144        ts << "RED";
145        break;
146    case CHANNEL_G:
147        ts << "GREEN";
148        break;
149    case CHANNEL_B:
150        ts << "BLUE";
151        break;
152    case CHANNEL_A:
153        ts << "ALPHA";
154        break;
155    }
156    return ts;
157}
158
159TextStream& FEDisplacementMap::externalRepresentation(TextStream& ts, int indent) const
160{
161    writeIndent(ts, indent);
162    ts << "[feDisplacementMap";
163    FilterEffect::externalRepresentation(ts);
164    ts << " scale=\"" << m_scale << "\" "
165       << "xChannelSelector=\"" << m_xChannelSelector << "\" "
166       << "yChannelSelector=\"" << m_yChannelSelector << "\"]\n";
167    inputEffect(0)->externalRepresentation(ts, indent + 1);
168    inputEffect(1)->externalRepresentation(ts, indent + 1);
169    return ts;
170}
171
172} // namespace WebCore
173
174#endif // ENABLE(FILTERS)
175