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
57bool FEDisplacementMap::setXChannelSelector(const ChannelSelectorType xChannelSelector)
58{
59    if (m_xChannelSelector == xChannelSelector)
60        return false;
61    m_xChannelSelector = xChannelSelector;
62    return true;
63}
64
65ChannelSelectorType FEDisplacementMap::yChannelSelector() const
66{
67    return m_yChannelSelector;
68}
69
70bool FEDisplacementMap::setYChannelSelector(const ChannelSelectorType yChannelSelector)
71{
72    if (m_yChannelSelector == yChannelSelector)
73        return false;
74    m_yChannelSelector = yChannelSelector;
75    return true;
76}
77
78float FEDisplacementMap::scale() const
79{
80    return m_scale;
81}
82
83bool FEDisplacementMap::setScale(float scale)
84{
85    if (m_scale == scale)
86        return false;
87    m_scale = scale;
88    return true;
89}
90
91void FEDisplacementMap::apply()
92{
93    if (hasResult())
94        return;
95    FilterEffect* in = inputEffect(0);
96    FilterEffect* in2 = inputEffect(1);
97    in->apply();
98    in2->apply();
99    if (!in->hasResult() || !in2->hasResult())
100        return;
101
102    if (m_xChannelSelector == CHANNEL_UNKNOWN || m_yChannelSelector == CHANNEL_UNKNOWN)
103        return;
104
105    ByteArray* dstPixelArray = createPremultipliedImageResult();
106    if (!dstPixelArray)
107        return;
108
109    IntRect effectADrawingRect = requestedRegionOfInputImageData(in->absolutePaintRect());
110    RefPtr<ByteArray> srcPixelArrayA = in->asPremultipliedImage(effectADrawingRect);
111
112    IntRect effectBDrawingRect = requestedRegionOfInputImageData(in2->absolutePaintRect());
113    RefPtr<ByteArray> srcPixelArrayB = in2->asUnmultipliedImage(effectBDrawingRect);
114
115    ASSERT(srcPixelArrayA->length() == srcPixelArrayB->length());
116
117    Filter* filter = this->filter();
118    IntSize paintSize = absolutePaintRect().size();
119    float scaleX = filter->applyHorizontalScale(m_scale / 255);
120    float scaleY = filter->applyVerticalScale(m_scale / 255);
121    float scaleAdjustmentX = filter->applyHorizontalScale(0.5f - 0.5f * m_scale);
122    float scaleAdjustmentY = filter->applyVerticalScale(0.5f - 0.5f * m_scale);
123    int stride = paintSize.width() * 4;
124    for (int y = 0; y < paintSize.height(); ++y) {
125        int line = y * stride;
126        for (int x = 0; x < paintSize.width(); ++x) {
127            int dstIndex = line + x * 4;
128            int srcX = x + static_cast<int>(scaleX * srcPixelArrayB->get(dstIndex + m_xChannelSelector - 1) + scaleAdjustmentX);
129            int srcY = y + static_cast<int>(scaleY * srcPixelArrayB->get(dstIndex + m_yChannelSelector - 1) + scaleAdjustmentY);
130            for (unsigned channel = 0; channel < 4; ++channel) {
131                if (srcX < 0 || srcX >= paintSize.width() || srcY < 0 || srcY >= paintSize.height())
132                    dstPixelArray->set(dstIndex + channel, static_cast<unsigned char>(0));
133                else {
134                    unsigned char pixelValue = srcPixelArrayA->get(srcY * stride + srcX * 4 + channel);
135                    dstPixelArray->set(dstIndex + channel, pixelValue);
136                }
137            }
138        }
139    }
140}
141
142void FEDisplacementMap::dump()
143{
144}
145
146static TextStream& operator<<(TextStream& ts, const ChannelSelectorType& type)
147{
148    switch (type) {
149    case CHANNEL_UNKNOWN:
150        ts << "UNKNOWN";
151        break;
152    case CHANNEL_R:
153        ts << "RED";
154        break;
155    case CHANNEL_G:
156        ts << "GREEN";
157        break;
158    case CHANNEL_B:
159        ts << "BLUE";
160        break;
161    case CHANNEL_A:
162        ts << "ALPHA";
163        break;
164    }
165    return ts;
166}
167
168TextStream& FEDisplacementMap::externalRepresentation(TextStream& ts, int indent) const
169{
170    writeIndent(ts, indent);
171    ts << "[feDisplacementMap";
172    FilterEffect::externalRepresentation(ts);
173    ts << " scale=\"" << m_scale << "\" "
174       << "xChannelSelector=\"" << m_xChannelSelector << "\" "
175       << "yChannelSelector=\"" << m_yChannelSelector << "\"]\n";
176    inputEffect(0)->externalRepresentation(ts, indent + 1);
177    inputEffect(1)->externalRepresentation(ts, indent + 1);
178    return ts;
179}
180
181} // namespace WebCore
182
183#endif // ENABLE(FILTERS)
184