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Diffstat (limited to 'Source/WebCore/html/HTMLCanvasElement.cpp')
| -rw-r--r-- | Source/WebCore/html/HTMLCanvasElement.cpp | 463 |
1 files changed, 463 insertions, 0 deletions
diff --git a/Source/WebCore/html/HTMLCanvasElement.cpp b/Source/WebCore/html/HTMLCanvasElement.cpp new file mode 100644 index 0000000..09e8d04 --- /dev/null +++ b/Source/WebCore/html/HTMLCanvasElement.cpp @@ -0,0 +1,463 @@ +/* + * Copyright (C) 2004, 2006, 2007 Apple Inc. All rights reserved. + * Copyright (C) 2007 Alp Toker <alp@atoker.com> + * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR + * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY + * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "config.h" +#include "HTMLCanvasElement.h" + +#include "Attribute.h" +#include "CanvasContextAttributes.h" +#include "CanvasGradient.h" +#include "CanvasPattern.h" +#include "CanvasRenderingContext2D.h" +#include "CanvasStyle.h" +#include "Chrome.h" +#include "Document.h" +#include "ExceptionCode.h" +#include "Frame.h" +#include "GraphicsContext.h" +#include "HTMLNames.h" +#include "ImageBuffer.h" +#include "MIMETypeRegistry.h" +#include "Page.h" +#include "RenderHTMLCanvas.h" +#include "Settings.h" +#include <math.h> +#include <stdio.h> + +#if USE(JSC) +#include <runtime/JSLock.h> +#endif + +#if ENABLE(WEBGL) +#include "WebGLContextAttributes.h" +#include "WebGLRenderingContext.h" +#endif + +namespace WebCore { + +using namespace HTMLNames; + +// These values come from the WhatWG spec. +static const int DefaultWidth = 300; +static const int DefaultHeight = 150; + +// Firefox limits width/height to 32767 pixels, but slows down dramatically before it +// reaches that limit. We limit by area instead, giving us larger maximum dimensions, +// in exchange for a smaller maximum canvas size. +static const float MaxCanvasArea = 32768 * 8192; // Maximum canvas area in CSS pixels + +//In Skia, we will also limit width/height to 32767. +static const float MaxSkiaDim = 32767.0F; // Maximum width/height in CSS pixels. + +HTMLCanvasElement::HTMLCanvasElement(const QualifiedName& tagName, Document* document) + : HTMLElement(tagName, document) + , m_size(DefaultWidth, DefaultHeight) + , m_ignoreReset(false) + , m_pageScaleFactor(document->frame() ? document->frame()->page()->chrome()->scaleFactor() : 1) + , m_originClean(true) + , m_hasCreatedImageBuffer(false) +{ + ASSERT(hasTagName(canvasTag)); +} + +PassRefPtr<HTMLCanvasElement> HTMLCanvasElement::create(Document* document) +{ + return adoptRef(new HTMLCanvasElement(canvasTag, document)); +} + +PassRefPtr<HTMLCanvasElement> HTMLCanvasElement::create(const QualifiedName& tagName, Document* document) +{ + return adoptRef(new HTMLCanvasElement(tagName, document)); +} + +HTMLCanvasElement::~HTMLCanvasElement() +{ + HashSet<CanvasObserver*>::iterator end = m_observers.end(); + for (HashSet<CanvasObserver*>::iterator it = m_observers.begin(); it != end; ++it) + (*it)->canvasDestroyed(this); +} + +void HTMLCanvasElement::parseMappedAttribute(Attribute* attr) +{ + const QualifiedName& attrName = attr->name(); + if (attrName == widthAttr || attrName == heightAttr) + reset(); + HTMLElement::parseMappedAttribute(attr); +} + +RenderObject* HTMLCanvasElement::createRenderer(RenderArena* arena, RenderStyle* style) +{ + Frame* frame = document()->frame(); + if (frame && frame->script()->canExecuteScripts(NotAboutToExecuteScript)) { + m_rendererIsCanvas = true; + return new (arena) RenderHTMLCanvas(this); + } + + m_rendererIsCanvas = false; + return HTMLElement::createRenderer(arena, style); +} + +void HTMLCanvasElement::addObserver(CanvasObserver* observer) +{ + m_observers.add(observer); +} + +void HTMLCanvasElement::removeObserver(CanvasObserver* observer) +{ + m_observers.remove(observer); +} + +void HTMLCanvasElement::setHeight(int value) +{ + setAttribute(heightAttr, String::number(value)); +} + +void HTMLCanvasElement::setWidth(int value) +{ + setAttribute(widthAttr, String::number(value)); +} + +CanvasRenderingContext* HTMLCanvasElement::getContext(const String& type, CanvasContextAttributes* attrs) +{ + // A Canvas can either be "2D" or "webgl" but never both. If you request a 2D canvas and the existing + // context is already 2D, just return that. If the existing context is WebGL, then destroy it + // before creating a new 2D context. Vice versa when requesting a WebGL canvas. Requesting a + // context with any other type string will destroy any existing context. + + // FIXME - The code depends on the context not going away once created, to prevent JS from + // seeing a dangling pointer. So for now we will disallow the context from being changed + // once it is created. + if (type == "2d") { + if (m_context && !m_context->is2d()) + return 0; + if (!m_context) { + bool usesDashbardCompatibilityMode = false; +#if ENABLE(DASHBOARD_SUPPORT) + if (Settings* settings = document()->settings()) + usesDashbardCompatibilityMode = settings->usesDashboardBackwardCompatibilityMode(); +#endif + m_context = adoptPtr(new CanvasRenderingContext2D(this, document()->inQuirksMode(), usesDashbardCompatibilityMode)); +#if USE(IOSURFACE_CANVAS_BACKING_STORE) || (ENABLE(ACCELERATED_2D_CANVAS) && USE(ACCELERATED_COMPOSITING)) + if (m_context) { + // Need to make sure a RenderLayer and compositing layer get created for the Canvas + setNeedsStyleRecalc(SyntheticStyleChange); + } +#endif + } + return m_context.get(); + } +#if ENABLE(WEBGL) + Settings* settings = document()->settings(); + if (settings && settings->webGLEnabled() +#if !PLATFORM(CHROMIUM) && !PLATFORM(QT) + && settings->acceleratedCompositingEnabled() +#endif + ) { + // Accept the legacy "webkit-3d" name as well as the provisional "experimental-webgl" name. + // Once ratified, we will also accept "webgl" as the context name. + if ((type == "webkit-3d") || + (type == "experimental-webgl")) { + if (m_context && !m_context->is3d()) + return 0; + if (!m_context) { + m_context = WebGLRenderingContext::create(this, static_cast<WebGLContextAttributes*>(attrs)); + if (m_context) { + // Need to make sure a RenderLayer and compositing layer get created for the Canvas + setNeedsStyleRecalc(SyntheticStyleChange); + } + } + return m_context.get(); + } + } +#else + UNUSED_PARAM(attrs); +#endif + return 0; +} + +void HTMLCanvasElement::didDraw(const FloatRect& rect) +{ + m_copiedImage.clear(); // Clear our image snapshot if we have one. + + if (RenderBox* ro = renderBox()) { + FloatRect destRect = ro->contentBoxRect(); + FloatRect r = mapRect(rect, FloatRect(0, 0, size().width(), size().height()), destRect); + r.intersect(destRect); + if (r.isEmpty() || m_dirtyRect.contains(r)) + return; + + m_dirtyRect.unite(r); + ro->repaintRectangle(enclosingIntRect(m_dirtyRect)); + } + + HashSet<CanvasObserver*>::iterator end = m_observers.end(); + for (HashSet<CanvasObserver*>::iterator it = m_observers.begin(); it != end; ++it) + (*it)->canvasChanged(this, rect); +} + +void HTMLCanvasElement::reset() +{ + if (m_ignoreReset) + return; + + bool ok; + bool hadImageBuffer = hasCreatedImageBuffer(); + int w = getAttribute(widthAttr).toInt(&ok); + if (!ok || w < 0) + w = DefaultWidth; + int h = getAttribute(heightAttr).toInt(&ok); + if (!ok || h < 0) + h = DefaultHeight; + + IntSize oldSize = size(); + setSurfaceSize(IntSize(w, h)); // The image buffer gets cleared here. + +#if ENABLE(WEBGL) + if (m_context && m_context->is3d() && oldSize != size()) + static_cast<WebGLRenderingContext*>(m_context.get())->reshape(width(), height()); +#endif + + if (m_context && m_context->is2d()) + static_cast<CanvasRenderingContext2D*>(m_context.get())->reset(); + + if (RenderObject* renderer = this->renderer()) { + if (m_rendererIsCanvas) { + if (oldSize != size()) + toRenderHTMLCanvas(renderer)->canvasSizeChanged(); + if (hadImageBuffer) + renderer->repaint(); + } + } + + HashSet<CanvasObserver*>::iterator end = m_observers.end(); + for (HashSet<CanvasObserver*>::iterator it = m_observers.begin(); it != end; ++it) + (*it)->canvasResized(this); +} + +void HTMLCanvasElement::paint(GraphicsContext* context, const IntRect& r) +{ + // Clear the dirty rect + m_dirtyRect = FloatRect(); + + if (context->paintingDisabled()) + return; + + if (m_context) { + if (!m_context->paintsIntoCanvasBuffer()) + return; + m_context->paintRenderingResultsToCanvas(); + } + + if (hasCreatedImageBuffer()) { + ImageBuffer* imageBuffer = buffer(); + if (imageBuffer) { + if (imageBuffer->drawsUsingCopy()) + context->drawImage(copiedImage(), ColorSpaceDeviceRGB, r); + else + context->drawImageBuffer(imageBuffer, ColorSpaceDeviceRGB, r); + } + } +} + +#if ENABLE(WEBGL) +bool HTMLCanvasElement::is3D() const +{ + return m_context && m_context->is3d(); +} +#endif + +void HTMLCanvasElement::makeRenderingResultsAvailable() +{ + if (m_context) + m_context->paintRenderingResultsToCanvas(); +} + +void HTMLCanvasElement::attach() +{ + HTMLElement::attach(); + + if (m_context && m_context->is2d()) { + CanvasRenderingContext2D* ctx = static_cast<CanvasRenderingContext2D*>(m_context.get()); + ctx->updateFont(); + } +} + +void HTMLCanvasElement::recalcStyle(StyleChange change) +{ + HTMLElement::recalcStyle(change); + + // Update font if needed. + if (change == Force && m_context && m_context->is2d()) { + CanvasRenderingContext2D* ctx = static_cast<CanvasRenderingContext2D*>(m_context.get()); + ctx->updateFont(); + } +} + +void HTMLCanvasElement::setSurfaceSize(const IntSize& size) +{ + m_size = size; + m_hasCreatedImageBuffer = false; + m_imageBuffer.clear(); + m_copiedImage.clear(); +} + +String HTMLCanvasElement::toDataURL(const String& mimeType, const double* quality, ExceptionCode& ec) +{ + if (!m_originClean) { + ec = SECURITY_ERR; + return String(); + } + + if (m_size.isEmpty() || !buffer()) + return String("data:,"); + + String lowercaseMimeType = mimeType.lower(); + + makeRenderingResultsAvailable(); + + // FIXME: Make isSupportedImageMIMETypeForEncoding threadsafe (to allow this method to be used on a worker thread). + if (mimeType.isNull() || !MIMETypeRegistry::isSupportedImageMIMETypeForEncoding(lowercaseMimeType)) + return buffer()->toDataURL("image/png"); + + return buffer()->toDataURL(lowercaseMimeType, quality); +} + +IntRect HTMLCanvasElement::convertLogicalToDevice(const FloatRect& logicalRect) const +{ + float left = floorf(logicalRect.x() * m_pageScaleFactor); + float top = floorf(logicalRect.y() * m_pageScaleFactor); + float right = ceilf(logicalRect.maxX() * m_pageScaleFactor); + float bottom = ceilf(logicalRect.maxY() * m_pageScaleFactor); + + return IntRect(IntPoint(left, top), convertToValidDeviceSize(right - left, bottom - top)); +} + +IntSize HTMLCanvasElement::convertLogicalToDevice(const FloatSize& logicalSize) const +{ + return convertToValidDeviceSize(logicalSize.width() * m_pageScaleFactor, logicalSize.height() * m_pageScaleFactor); +} + +IntSize HTMLCanvasElement::convertToValidDeviceSize(float width, float height) const +{ + width = ceilf(width); + height = ceilf(height); + + if (width < 1 || height < 1 || width * height > MaxCanvasArea) + return IntSize(); + +#if PLATFORM(SKIA) + if (width > MaxSkiaDim || height > MaxSkiaDim) + return IntSize(); +#endif + + return IntSize(width, height); +} + +const SecurityOrigin& HTMLCanvasElement::securityOrigin() const +{ + return *document()->securityOrigin(); +} + +CSSStyleSelector* HTMLCanvasElement::styleSelector() +{ + return document()->styleSelector(); +} + +void HTMLCanvasElement::createImageBuffer() const +{ + ASSERT(!m_imageBuffer); + + m_hasCreatedImageBuffer = true; + + FloatSize unscaledSize(width(), height()); + IntSize size = convertLogicalToDevice(unscaledSize); + if (!size.width() || !size.height()) + return; + +#if USE(IOSURFACE_CANVAS_BACKING_STORE) + m_imageBuffer = ImageBuffer::create(size, ColorSpaceDeviceRGB, Accelerated); +#else + m_imageBuffer = ImageBuffer::create(size); +#endif + // The convertLogicalToDevice MaxCanvasArea check should prevent common cases + // where ImageBuffer::create() returns 0, however we could still be low on memory. + if (!m_imageBuffer) + return; + m_imageBuffer->context()->scale(FloatSize(size.width() / unscaledSize.width(), size.height() / unscaledSize.height())); + m_imageBuffer->context()->setShadowsIgnoreTransforms(true); + m_imageBuffer->context()->setImageInterpolationQuality(DefaultInterpolationQuality); + +#if USE(JSC) + if (hasCachedDOMNodeWrapperUnchecked(document(), const_cast<HTMLCanvasElement*>(this))) { + JSC::JSLock lock(JSC::SilenceAssertionsOnly); + scriptExecutionContext()->globalData()->heap.reportExtraMemoryCost(m_imageBuffer->dataSize()); + } +#endif +} + +GraphicsContext* HTMLCanvasElement::drawingContext() const +{ + return buffer() ? m_imageBuffer->context() : 0; +} + +ImageBuffer* HTMLCanvasElement::buffer() const +{ + if (!m_hasCreatedImageBuffer) + createImageBuffer(); + return m_imageBuffer.get(); +} + +Image* HTMLCanvasElement::copiedImage() const +{ + if (!m_copiedImage && buffer()) { + if (m_context) { + // If we're not rendering to the ImageBuffer, copy the rendering results to it. + if (!m_context->paintsIntoCanvasBuffer()) + m_context->paintRenderingResultsToCanvas(); + } + m_copiedImage = buffer()->copyImage(); + } + return m_copiedImage.get(); +} + +void HTMLCanvasElement::clearCopiedImage() +{ + m_copiedImage.clear(); +} + +AffineTransform HTMLCanvasElement::baseTransform() const +{ + ASSERT(m_hasCreatedImageBuffer); + FloatSize unscaledSize(width(), height()); + IntSize size = convertLogicalToDevice(unscaledSize); + AffineTransform transform; + if (size.width() && size.height()) + transform.scaleNonUniform(size.width() / unscaledSize.width(), size.height() / unscaledSize.height()); + return m_imageBuffer->baseTransform() * transform; +} + +} |