1 /* 2 * Copyright (C) 2010 Google Inc. All rights reserved. 3 * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY 15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 17 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR 18 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 21 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 22 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include "config.h" 28 #include "CanvasSurface.h" 29 30 #include "AffineTransform.h" 31 #include "ExceptionCode.h" 32 #include "FloatRect.h" 33 #include "GraphicsContext.h" 34 #include "HTMLCanvasElement.h" 35 #include "ImageBuffer.h" 36 #include "MIMETypeRegistry.h" 37 38 namespace WebCore { 39 40 // These values come from the WhatWG spec. 41 const int CanvasSurface::DefaultWidth = 300; 42 const int CanvasSurface::DefaultHeight = 150; 43 44 // Firefox limits width/height to 32767 pixels, but slows down dramatically before it 45 // reaches that limit. We limit by area instead, giving us larger maximum dimensions, 46 // in exchange for a smaller maximum canvas size. 47 const float CanvasSurface::MaxCanvasArea = 32768 * 8192; // Maximum canvas area in CSS pixels 48 49 CanvasSurface::CanvasSurface(float pageScaleFactor) 50 : m_size(DefaultWidth, DefaultHeight) 51 #if PLATFORM(ANDROID) 52 /* In Android we capture the drawing into a displayList, and then replay 53 * that list at various scale factors (sometimes zoomed out, other times 54 * zoomed in for "normal" reading, yet other times at arbitrary zoom values 55 * based on the user's choice). In all of these cases, we do not re-record 56 * the displayList, hence it is usually harmful to perform any pre-rounding, 57 * since we just don't know the actual drawing resolution at record time. 58 */ 59 // TODO - may be better to move the ifdef to the call site of this 60 // constructor 61 , m_pageScaleFactor(1.0f) 62 #else 63 , m_pageScaleFactor(pageScaleFactor) 64 #endif 65 , m_originClean(true) 66 , m_hasCreatedImageBuffer(false) 67 { 68 } 69 70 CanvasSurface::~CanvasSurface() 71 { 72 } 73 74 void CanvasSurface::setSurfaceSize(const IntSize& size) 75 { 76 m_size = size; 77 m_hasCreatedImageBuffer = false; 78 m_imageBuffer.clear(); 79 } 80 81 String CanvasSurface::toDataURL(const String& mimeType, const double* quality, ExceptionCode& ec) 82 { 83 if (!m_originClean) { 84 ec = SECURITY_ERR; 85 return String(); 86 } 87 88 if (m_size.isEmpty() || !buffer()) 89 return String("data:,"); 90 91 String lowercaseMimeType = mimeType.lower(); 92 93 // FIXME: Make isSupportedImageMIMETypeForEncoding threadsafe (to allow this method to be used on a worker thread). 94 if (mimeType.isNull() || !MIMETypeRegistry::isSupportedImageMIMETypeForEncoding(lowercaseMimeType)) 95 return buffer()->toDataURL("image/png"); 96 97 return buffer()->toDataURL(lowercaseMimeType, quality); 98 } 99 100 void CanvasSurface::willDraw(const FloatRect&) 101 { 102 if (m_imageBuffer) 103 m_imageBuffer->clearImage(); 104 } 105 106 IntRect CanvasSurface::convertLogicalToDevice(const FloatRect& logicalRect) const 107 { 108 return IntRect(convertLogicalToDevice(logicalRect.location()), convertLogicalToDevice(logicalRect.size())); 109 } 110 111 IntSize CanvasSurface::convertLogicalToDevice(const FloatSize& logicalSize) const 112 { 113 float wf = ceilf(logicalSize.width() * m_pageScaleFactor); 114 float hf = ceilf(logicalSize.height() * m_pageScaleFactor); 115 116 if (!(wf >= 1 && hf >= 1 && wf * hf <= MaxCanvasArea)) 117 return IntSize(); 118 119 return IntSize(static_cast<unsigned>(wf), static_cast<unsigned>(hf)); 120 } 121 122 IntPoint CanvasSurface::convertLogicalToDevice(const FloatPoint& logicalPos) const 123 { 124 float xf = logicalPos.x() * m_pageScaleFactor; 125 float yf = logicalPos.y() * m_pageScaleFactor; 126 127 return IntPoint(static_cast<unsigned>(xf), static_cast<unsigned>(yf)); 128 } 129 130 void CanvasSurface::createImageBuffer() const 131 { 132 ASSERT(!m_imageBuffer); 133 134 m_hasCreatedImageBuffer = true; 135 136 FloatSize unscaledSize(width(), height()); 137 IntSize size = convertLogicalToDevice(unscaledSize); 138 if (!size.width() || !size.height()) 139 return; 140 141 m_imageBuffer = ImageBuffer::create(size); 142 // The convertLogicalToDevice MaxCanvasArea check should prevent common cases 143 // where ImageBuffer::create() returns 0, however we could still be low on memory. 144 if (!m_imageBuffer) 145 return; 146 m_imageBuffer->context()->scale(FloatSize(size.width() / unscaledSize.width(), size.height() / unscaledSize.height())); 147 m_imageBuffer->context()->setShadowsIgnoreTransforms(true); 148 } 149 150 GraphicsContext* CanvasSurface::drawingContext() const 151 { 152 return buffer() ? m_imageBuffer->context() : 0; 153 } 154 155 ImageBuffer* CanvasSurface::buffer() const 156 { 157 if (!m_hasCreatedImageBuffer) 158 createImageBuffer(); 159 return m_imageBuffer.get(); 160 } 161 162 AffineTransform CanvasSurface::baseTransform() const 163 { 164 ASSERT(m_hasCreatedImageBuffer); 165 FloatSize unscaledSize(width(), height()); 166 IntSize size = convertLogicalToDevice(unscaledSize); 167 AffineTransform transform; 168 if (size.width() && size.height()) 169 transform.scaleNonUniform(size.width() / unscaledSize.width(), size.height() / unscaledSize.height()); 170 transform.multiply(m_imageBuffer->baseTransform()); 171 return transform; 172 } 173 174 // FIXME: Everything below here relies on CanvasSurface really being 175 // a HTMLCanvasElement. 176 const SecurityOrigin& CanvasSurface::securityOrigin() const 177 { 178 return *(static_cast<const HTMLCanvasElement*>(this)->document()->securityOrigin()); 179 } 180 181 RenderBox* CanvasSurface::renderBox() const 182 { 183 return static_cast<const HTMLCanvasElement*>(this)->renderBox(); 184 } 185 186 RenderStyle* CanvasSurface::computedStyle() 187 { 188 return static_cast<HTMLCanvasElement*>(this)->computedStyle(); 189 } 190 191 CSSStyleSelector* CanvasSurface::styleSelector() 192 { 193 return static_cast<HTMLCanvasElement*>(this)->document()->styleSelector(); 194 } 195 196 } // namespace WebCore 197