--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/WebCore/html/HTMLCanvasElement.cpp Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,432 @@
+/*
+ * 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 ENABLE(3D_CANVAS)
+#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_observer(0)
+ , 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()
+{
+ if (m_observer)
+ m_observer->canvasDestroyed(this);
+}
+
+#if ENABLE(DASHBOARD_SUPPORT)
+
+HTMLTagStatus HTMLCanvasElement::endTagRequirement() const
+{
+ Settings* settings = document()->settings();
+ if (settings && settings->usesDashboardBackwardCompatibilityMode())
+ return TagStatusForbidden;
+
+ return HTMLElement::endTagRequirement();
+}
+
+int HTMLCanvasElement::tagPriority() const
+{
+ Settings* settings = document()->settings();
+ if (settings && settings->usesDashboardBackwardCompatibilityMode())
+ return 0;
+
+ return HTMLElement::tagPriority();
+}
+
+#endif
+
+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::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 = new CanvasRenderingContext2D(this, document()->inCompatMode(), usesDashbardCompatibilityMode);
+ }
+ return m_context.get();
+ }
+#if ENABLE(3D_CANVAS)
+ 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::willDraw(const FloatRect& rect)
+{
+ if (m_imageBuffer)
+ m_imageBuffer->clearImage();
+
+ if (RenderBox* ro = renderBox()) {
+ FloatRect destRect = ro->contentBoxRect();
+ FloatRect r = mapRect(rect, FloatRect(0, 0, size().width(), size().height()), destRect);
+ r.intersect(destRect);
+ if (m_dirtyRect.contains(r))
+ return;
+
+ m_dirtyRect.unite(r);
+ ro->repaintRectangle(enclosingIntRect(m_dirtyRect));
+ }
+
+ if (m_observer)
+ m_observer->canvasChanged(this, rect);
+}
+
+void HTMLCanvasElement::reset()
+{
+ if (m_ignoreReset)
+ return;
+
+ bool ok;
+ 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));
+
+#if ENABLE(3D_CANVAS)
+ if (m_context && m_context->is3d())
+ static_cast<WebGLRenderingContext*>(m_context.get())->reshape(width(), height());
+#endif
+
+ bool hadImageBuffer = hasCreatedImageBuffer();
+ 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();
+ }
+ }
+
+ if (m_observer)
+ m_observer->canvasResized(this);
+}
+
+void HTMLCanvasElement::paint(GraphicsContext* context, const IntRect& r)
+{
+ // Clear the dirty rect
+ m_dirtyRect = FloatRect();
+
+ if (context->paintingDisabled())
+ return;
+
+#if ENABLE(3D_CANVAS)
+ WebGLRenderingContext* context3D = 0;
+ if (m_context && m_context->is3d()) {
+ context3D = static_cast<WebGLRenderingContext*>(m_context.get());
+ context3D->beginPaint();
+ }
+#endif
+
+ if (hasCreatedImageBuffer()) {
+ ImageBuffer* imageBuffer = buffer();
+ if (imageBuffer) {
+ Image* image = imageBuffer->imageForRendering();
+ if (image)
+ context->drawImage(image, DeviceColorSpace, r);
+ }
+ }
+
+#if ENABLE(3D_CANVAS)
+ if (context3D)
+ context3D->endPaint();
+#endif
+}
+
+#if ENABLE(3D_CANVAS)
+bool HTMLCanvasElement::is3D() const
+{
+ return m_context && m_context->is3d();
+}
+#endif
+
+void HTMLCanvasElement::makeRenderingResultsAvailable()
+{
+#if ENABLE(3D_CANVAS)
+ if (is3D()) {
+ WebGLRenderingContext* context3d = reinterpret_cast<WebGLRenderingContext*>(renderingContext());
+ context3d->paintRenderingResultsToCanvas();
+ }
+#endif
+}
+
+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();
+}
+
+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
+{
+ return IntRect(convertLogicalToDevice(logicalRect.location()), convertLogicalToDevice(logicalRect.size()));
+}
+
+IntSize HTMLCanvasElement::convertLogicalToDevice(const FloatSize& logicalSize) const
+{
+ float wf = ceilf(logicalSize.width() * m_pageScaleFactor);
+ float hf = ceilf(logicalSize.height() * m_pageScaleFactor);
+
+ if (!(wf >= 1 && hf >= 1 && wf * hf <= MaxCanvasArea))
+ return IntSize();
+
+#if PLATFORM(SKIA)
+ if (wf > MaxSkiaDim || hf > MaxSkiaDim)
+ return IntSize();
+#endif
+
+ return IntSize(static_cast<unsigned>(wf), static_cast<unsigned>(hf));
+}
+
+IntPoint HTMLCanvasElement::convertLogicalToDevice(const FloatPoint& logicalPos) const
+{
+ float xf = logicalPos.x() * m_pageScaleFactor;
+ float yf = logicalPos.y() * m_pageScaleFactor;
+
+ return IntPoint(static_cast<unsigned>(xf), static_cast<unsigned>(yf));
+}
+
+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;
+
+ m_imageBuffer = ImageBuffer::create(size);
+ // 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);
+}
+
+GraphicsContext* HTMLCanvasElement::drawingContext() const
+{
+ return buffer() ? m_imageBuffer->context() : 0;
+}
+
+ImageBuffer* HTMLCanvasElement::buffer() const
+{
+ if (!m_hasCreatedImageBuffer)
+ createImageBuffer();
+ return m_imageBuffer.get();
+}
+
+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());
+ transform.multiply(m_imageBuffer->baseTransform());
+ return transform;
+}
+
+}