diff -r 000000000000 -r 4f2f89ce4247 WebCore/html/HTMLCanvasElement.cpp
--- /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;
+}
+
+}