1 /*
2 * Copyright (C) 2010 Sencha, Inc.
3 *
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
16 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR
19 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
22 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
23 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
25 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28 #include "config.h"
29 #include "ContextShadow.h"
30
31 #include "AffineTransform.h"
32 #include "GraphicsContext.h"
33 #include <QPainter>
34 #include <QTimerEvent>
35
36 namespace WebCore {
37
38 // ContextShadow needs a scratch image as the buffer for the blur filter.
39 // Instead of creating and destroying the buffer for every operation,
40 // we create a buffer which will be automatically purged via a timer.
41
42 class ShadowBuffer: public QObject {
43 public:
44 ShadowBuffer(QObject* parent = 0);
45
46 QImage* scratchImage(const QSize& size);
47
48 void schedulePurge();
49
50 protected:
51 void timerEvent(QTimerEvent* event);
52
53 private:
54 QImage image;
55 int timerId;
56 };
57
ShadowBuffer(QObject * parent)58 ShadowBuffer::ShadowBuffer(QObject* parent)
59 : QObject(parent)
60 , timerId(-1)
61 {
62 }
63
scratchImage(const QSize & size)64 QImage* ShadowBuffer::scratchImage(const QSize& size)
65 {
66 int width = size.width();
67 int height = size.height();
68
69 // We do not need to recreate the buffer if the buffer is reasonably
70 // larger than the requested size. However, if the requested size is
71 // much smaller than our buffer, reduce our buffer so that we will not
72 // keep too many allocated pixels for too long.
73 if (!image.isNull() && (image.width() > width) && (image.height() > height))
74 if (((2 * width) > image.width()) && ((2 * height) > image.height())) {
75 image.fill(0);
76 return ℑ
77 }
78
79 // Round to the nearest 32 pixels so we do not grow the buffer everytime
80 // there is larger request by 1 pixel.
81 width = (1 + (width >> 5)) << 5;
82 height = (1 + (height >> 5)) << 5;
83
84 image = QImage(width, height, QImage::Format_ARGB32_Premultiplied);
85 image.fill(0);
86 return ℑ
87 }
88
schedulePurge()89 void ShadowBuffer::schedulePurge()
90 {
91 static const double BufferPurgeDelay = 2; // seconds
92 if (timerId >= 0)
93 killTimer(timerId);
94 timerId = startTimer(BufferPurgeDelay * 1000);
95 }
96
timerEvent(QTimerEvent * event)97 void ShadowBuffer::timerEvent(QTimerEvent* event)
98 {
99 if (event->timerId() == timerId) {
100 killTimer(timerId);
101 image = QImage();
102 }
103 QObject::timerEvent(event);
104 }
105
Q_GLOBAL_STATIC(ShadowBuffer,scratchShadowBuffer)106 Q_GLOBAL_STATIC(ShadowBuffer, scratchShadowBuffer)
107
108 PlatformContext ContextShadow::beginShadowLayer(GraphicsContext* context, const FloatRect& layerArea)
109 {
110 // Set m_blurDistance.
111 adjustBlurDistance(context);
112
113 PlatformContext p = context->platformContext();
114
115 QRect clipRect;
116 if (p->hasClipping())
117 #if QT_VERSION >= QT_VERSION_CHECK(4, 8, 0)
118 clipRect = p->clipBoundingRect().toAlignedRect();
119 #else
120 clipRect = p->clipRegion().boundingRect();
121 #endif
122 else
123 clipRect = p->transform().inverted().mapRect(p->window());
124
125 // Set m_layerOrigin, m_layerContextTranslation, m_sourceRect.
126 IntRect clip(clipRect.x(), clipRect.y(), clipRect.width(), clipRect.height());
127 IntRect layerRect = calculateLayerBoundingRect(context, layerArea, clip);
128
129 // Don't paint if we are totally outside the clip region.
130 if (layerRect.isEmpty())
131 return 0;
132
133 ShadowBuffer* shadowBuffer = scratchShadowBuffer();
134 QImage* shadowImage = shadowBuffer->scratchImage(layerRect.size());
135 m_layerImage = QImage(*shadowImage);
136
137 m_layerContext = new QPainter;
138 m_layerContext->begin(&m_layerImage);
139 m_layerContext->setFont(p->font());
140 m_layerContext->translate(m_layerContextTranslation);
141 return m_layerContext;
142 }
143
endShadowLayer(GraphicsContext * context)144 void ContextShadow::endShadowLayer(GraphicsContext* context)
145 {
146 m_layerContext->end();
147 delete m_layerContext;
148 m_layerContext = 0;
149
150 if (m_type == BlurShadow) {
151 blurLayerImage(m_layerImage.bits(), IntSize(m_layerImage.width(), m_layerImage.height()),
152 m_layerImage.bytesPerLine());
153 }
154
155 if (m_type != NoShadow) {
156 // "Colorize" with the right shadow color.
157 QPainter p(&m_layerImage);
158 p.setCompositionMode(QPainter::CompositionMode_SourceIn);
159 p.fillRect(m_layerImage.rect(), m_color.rgb());
160 p.end();
161 }
162
163 context->platformContext()->drawImage(m_layerOrigin, m_layerImage, m_sourceRect);
164
165 scratchShadowBuffer()->schedulePurge();
166 }
167
168 }
169