root/Source/core/rendering/svg/RenderSVGRoot.cpp

DEFINITIONS

1. m_needsBoundariesOrTransformUpdate
2. computeIntrinsicRatioInformation
3. isEmbeddedThroughSVGImage
4. isEmbeddedThroughFrameContainingSVGDocument
5. resolveLengthAttributeForSVG
6. computeReplacedLogicalWidth
7. computeReplacedLogicalHeight
8. layout
9. paintReplaced
10. willBeDestroyed
11. styleDidChange
12. isChildAllowed
13. addChild
14. removeChild
15. insertedIntoTree
16. willBeRemovedFromTree
17. buildLocalToBorderBoxTransform
18. localToParentTransform
19. clippedOverflowRectForRepaint
20. computeFloatRectForRepaint
21. mapLocalToContainer
22. pushMappingToContainer
23. updateCachedBoundaries
24. nodeAtPoint
25. hasRelativeIntrinsicLogicalWidth
26. hasRelativeLogicalHeight

/*
 * Copyright (C) 2004, 2005, 2007 Nikolas Zimmermann <zimmermann@kde.org>
 * Copyright (C) 2004, 2005, 2007, 2008, 2009 Rob Buis <buis@kde.org>
 * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
 * Copyright (C) 2009 Google, Inc.
 * Copyright (C) Research In Motion Limited 2011. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "config.h"

#include "core/rendering/svg/RenderSVGRoot.h"

#include "core/frame/LocalFrame.h"
#include "core/rendering/HitTestResult.h"
#include "core/rendering/LayoutRectRecorder.h"
#include "core/rendering/LayoutRepainter.h"
#include "core/rendering/RenderPart.h"
#include "core/rendering/RenderView.h"
#include "core/rendering/svg/RenderSVGResourceContainer.h"
#include "core/rendering/svg/SVGRenderingContext.h"
#include "core/rendering/svg/SVGResources.h"
#include "core/rendering/svg/SVGResourcesCache.h"
#include "core/svg/SVGElement.h"
#include "core/svg/SVGSVGElement.h"
#include "core/svg/graphics/SVGImage.h"
#include "platform/LengthFunctions.h"
#include "platform/graphics/GraphicsContext.h"

using namespace std;

namespace WebCore {

RenderSVGRoot::RenderSVGRoot(SVGElement* node)
    : RenderReplaced(node)
    , m_objectBoundingBoxValid(false)
    , m_isLayoutSizeChanged(false)
    , m_needsBoundariesOrTransformUpdate(true)
{
}

RenderSVGRoot::~RenderSVGRoot()
{
}

void RenderSVGRoot::computeIntrinsicRatioInformation(FloatSize& intrinsicSize, double& intrinsicRatio, bool& isPercentageIntrinsicSize) const
{
    // Spec: http://www.w3.org/TR/SVG/coords.html#IntrinsicSizing
    // SVG needs to specify how to calculate some intrinsic sizing properties to enable inclusion within other languages.
    // The intrinsic width and height of the viewport of SVG content must be determined from the ‘width’ and ‘height’ attributes.
    // If either of these are not specified, a value of '100%' must be assumed. Note: the ‘width’ and ‘height’ attributes are not
    // the same as the CSS width and height properties. Specifically, percentage values do not provide an intrinsic width or height,
    // and do not indicate a percentage of the containing block. Rather, once the viewport is established, they indicate the portion
    // of the viewport that is actually covered by image data.
    SVGSVGElement* svg = toSVGSVGElement(node());
    ASSERT(svg);
    Length intrinsicWidthAttribute = svg->intrinsicWidth(SVGSVGElement::IgnoreCSSProperties);
    Length intrinsicHeightAttribute = svg->intrinsicHeight(SVGSVGElement::IgnoreCSSProperties);

    // The intrinsic aspect ratio of the viewport of SVG content is necessary for example, when including SVG from an ‘object’
    // element in HTML styled with CSS. It is possible (indeed, common) for an SVG graphic to have an intrinsic aspect ratio but
    // not to have an intrinsic width or height. The intrinsic aspect ratio must be calculated based upon the following rules:
    // - The aspect ratio is calculated by dividing a width by a height.
    // - If the ‘width’ and ‘height’ of the rootmost ‘svg’ element are both specified with unit identifiers (in, mm, cm, pt, pc,
    //   px, em, ex) or in user units, then the aspect ratio is calculated from the ‘width’ and ‘height’ attributes after
    //   resolving both values to user units.
    if (intrinsicWidthAttribute.isFixed() || intrinsicHeightAttribute.isFixed()) {
        if (intrinsicWidthAttribute.isFixed())
            intrinsicSize.setWidth(floatValueForLength(intrinsicWidthAttribute, 0));
        if (intrinsicHeightAttribute.isFixed())
            intrinsicSize.setHeight(floatValueForLength(intrinsicHeightAttribute, 0));
        if (!intrinsicSize.isEmpty())
            intrinsicRatio = intrinsicSize.width() / static_cast<double>(intrinsicSize.height());
        return;
    }

    // - If either/both of the ‘width’ and ‘height’ of the rootmost ‘svg’ element are in percentage units (or omitted), the
    //   aspect ratio is calculated from the width and height values of the ‘viewBox’ specified for the current SVG document
    //   fragment. If the ‘viewBox’ is not correctly specified, or set to 'none', the intrinsic aspect ratio cannot be
    //   calculated and is considered unspecified.
    intrinsicSize = svg->viewBox()->currentValue()->value().size();
    if (!intrinsicSize.isEmpty()) {
        // The viewBox can only yield an intrinsic ratio, not an intrinsic size.
        intrinsicRatio = intrinsicSize.width() / static_cast<double>(intrinsicSize.height());
        intrinsicSize = FloatSize();
        return;
    }

    // If our intrinsic size is in percentage units, return those to the caller through the intrinsicSize. Notify the caller
    // about the special situation, by setting isPercentageIntrinsicSize=true, so it knows how to interpret the return values.
    if (intrinsicWidthAttribute.isPercent() && intrinsicHeightAttribute.isPercent()) {
        isPercentageIntrinsicSize = true;
        intrinsicSize = FloatSize(intrinsicWidthAttribute.percent(), intrinsicHeightAttribute.percent());
    }
}

bool RenderSVGRoot::isEmbeddedThroughSVGImage() const
{
    return SVGImage::isInSVGImage(toSVGSVGElement(node()));
}

bool RenderSVGRoot::isEmbeddedThroughFrameContainingSVGDocument() const
{
    if (!node())
        return false;

    LocalFrame* frame = node()->document().frame();
    if (!frame)
        return false;

    // If our frame has an owner renderer, we're embedded through eg. object/embed/iframe,
    // but we only negotiate if we're in an SVG document.
    if (!frame->ownerRenderer())
        return false;
    return frame->document()->isSVGDocument();
}

static inline LayoutUnit resolveLengthAttributeForSVG(const Length& length, float scale, float maxSize)
{
    return static_cast<LayoutUnit>(valueForLength(length, maxSize) * (length.isFixed() ? scale : 1));
}

LayoutUnit RenderSVGRoot::computeReplacedLogicalWidth(ShouldComputePreferred shouldComputePreferred) const
{
    SVGSVGElement* svg = toSVGSVGElement(node());
    ASSERT(svg);

    // When we're embedded through SVGImage (border-image/background-image/<html:img>/...) we're forced to resize to a specific size.
    if (!m_containerSize.isEmpty())
        return m_containerSize.width();

    if (style()->logicalWidth().isSpecified() || style()->logicalMaxWidth().isSpecified())
        return RenderReplaced::computeReplacedLogicalWidth(shouldComputePreferred);

    if (svg->widthAttributeEstablishesViewport())
        return resolveLengthAttributeForSVG(svg->intrinsicWidth(SVGSVGElement::IgnoreCSSProperties), style()->effectiveZoom(), containingBlock()->availableLogicalWidth().toFloat());

    // SVG embedded through object/embed/iframe.
    if (isEmbeddedThroughFrameContainingSVGDocument())
        return document().frame()->ownerRenderer()->availableLogicalWidth();

    // SVG embedded via SVGImage (background-image/border-image/etc) / Inline SVG.
    return RenderReplaced::computeReplacedLogicalWidth(shouldComputePreferred);
}

LayoutUnit RenderSVGRoot::computeReplacedLogicalHeight() const
{
    SVGSVGElement* svg = toSVGSVGElement(node());
    ASSERT(svg);

    // When we're embedded through SVGImage (border-image/background-image/<html:img>/...) we're forced to resize to a specific size.
    if (!m_containerSize.isEmpty())
        return m_containerSize.height();

    if (style()->logicalHeight().isSpecified() || style()->logicalMaxHeight().isSpecified())
        return RenderReplaced::computeReplacedLogicalHeight();

    if (svg->heightAttributeEstablishesViewport()) {
        Length height = svg->intrinsicHeight(SVGSVGElement::IgnoreCSSProperties);
        if (height.isPercent()) {
            RenderBlock* cb = containingBlock();
            ASSERT(cb);
            while (cb->isAnonymous())
                cb = cb->containingBlock();
            cb->addPercentHeightDescendant(const_cast<RenderSVGRoot*>(this));
        } else
            RenderBlock::removePercentHeightDescendant(const_cast<RenderSVGRoot*>(this));

        return resolveLengthAttributeForSVG(height, style()->effectiveZoom(), containingBlock()->availableLogicalHeight(IncludeMarginBorderPadding).toFloat());
    }

    // SVG embedded through object/embed/iframe.
    if (isEmbeddedThroughFrameContainingSVGDocument())
        return document().frame()->ownerRenderer()->availableLogicalHeight(IncludeMarginBorderPadding);

    // SVG embedded via SVGImage (background-image/border-image/etc) / Inline SVG.
    return RenderReplaced::computeReplacedLogicalHeight();
}

void RenderSVGRoot::layout()
{
    ASSERT(needsLayout());

    // Arbitrary affine transforms are incompatible with LayoutState.
    LayoutStateDisabler layoutStateDisabler(*this);

    bool needsLayout = selfNeedsLayout();
    LayoutRectRecorder recorder(*this, checkForRepaint() && needsLayout);
    LayoutRepainter repainter(*this, checkForRepaintDuringLayout() && needsLayout);

    LayoutSize oldSize = size();
    updateLogicalWidth();
    updateLogicalHeight();
    buildLocalToBorderBoxTransform();

    SVGRenderSupport::layoutResourcesIfNeeded(this);

    SVGSVGElement* svg = toSVGSVGElement(node());
    ASSERT(svg);
    m_isLayoutSizeChanged = needsLayout || (svg->hasRelativeLengths() && oldSize != size());
    SVGRenderSupport::layoutChildren(this, needsLayout || SVGRenderSupport::filtersForceContainerLayout(this));

    // At this point LayoutRepainter already grabbed the old bounds,
    // recalculate them now so repaintAfterLayout() uses the new bounds.
    if (m_needsBoundariesOrTransformUpdate) {
        updateCachedBoundaries();
        m_needsBoundariesOrTransformUpdate = false;
    }

    updateLayerTransform();

    repainter.repaintAfterLayout();

    clearNeedsLayout();
}

void RenderSVGRoot::paintReplaced(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
{
    // An empty viewport disables rendering.
    if (pixelSnappedBorderBoxRect().isEmpty())
        return;

    // Don't paint, if the context explicitly disabled it.
    if (paintInfo.context->paintingDisabled())
        return;

    // An empty viewBox also disables rendering.
    // (http://www.w3.org/TR/SVG/coords.html#ViewBoxAttribute)
    SVGSVGElement* svg = toSVGSVGElement(node());
    ASSERT(svg);
    if (svg->hasEmptyViewBox())
        return;

    // Don't paint if we don't have kids, except if we have filters we should paint those.
    if (!firstChild()) {
        SVGResources* resources = SVGResourcesCache::cachedResourcesForRenderObject(this);
        if (!resources || !resources->filter())
            return;
    }

    // Make a copy of the PaintInfo because applyTransform will modify the damage rect.
    PaintInfo childPaintInfo(paintInfo);
    childPaintInfo.context->save();

    // Apply initial viewport clip - not affected by overflow handling
    childPaintInfo.context->clip(pixelSnappedIntRect(overflowClipRect(paintOffset)));

    // Convert from container offsets (html renderers) to a relative transform (svg renderers).
    // Transform from our paint container's coordinate system to our local coords.
    IntPoint adjustedPaintOffset = roundedIntPoint(paintOffset);
    childPaintInfo.applyTransform(AffineTransform::translation(adjustedPaintOffset.x(), adjustedPaintOffset.y()) * localToBorderBoxTransform());

    // SVGRenderingContext must be destroyed before we restore the childPaintInfo.context, because a filter may have
    // changed the context and it is only reverted when the SVGRenderingContext destructor finishes applying the filter.
    {
        SVGRenderingContext renderingContext;
        bool continueRendering = true;
        if (childPaintInfo.phase == PaintPhaseForeground) {
            renderingContext.prepareToRenderSVGContent(this, childPaintInfo);
            continueRendering = renderingContext.isRenderingPrepared();
        }

        if (continueRendering)
            RenderBox::paint(childPaintInfo, LayoutPoint());
    }

    childPaintInfo.context->restore();
}

void RenderSVGRoot::willBeDestroyed()
{
    RenderBlock::removePercentHeightDescendant(const_cast<RenderSVGRoot*>(this));

    SVGResourcesCache::clientDestroyed(this);
    RenderReplaced::willBeDestroyed();
}

void RenderSVGRoot::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
{
    if (diff == StyleDifferenceLayout)
        setNeedsBoundariesUpdate();

    RenderReplaced::styleDidChange(diff, oldStyle);
    SVGResourcesCache::clientStyleChanged(this, diff, style());
}

bool RenderSVGRoot::isChildAllowed(RenderObject* child, RenderStyle*) const
{
    return child->isSVG() && !(child->isSVGInline() || child->isSVGInlineText());
}

void RenderSVGRoot::addChild(RenderObject* child, RenderObject* beforeChild)
{
    RenderReplaced::addChild(child, beforeChild);
    SVGResourcesCache::clientWasAddedToTree(child, child->style());
}

void RenderSVGRoot::removeChild(RenderObject* child)
{
    SVGResourcesCache::clientWillBeRemovedFromTree(child);
    RenderReplaced::removeChild(child);
}

void RenderSVGRoot::insertedIntoTree()
{
    RenderReplaced::insertedIntoTree();
    SVGResourcesCache::clientWasAddedToTree(this, style());
}

void RenderSVGRoot::willBeRemovedFromTree()
{
    SVGResourcesCache::clientWillBeRemovedFromTree(this);
    RenderReplaced::willBeRemovedFromTree();
}

// RenderBox methods will expect coordinates w/o any transforms in coordinates
// relative to our borderBox origin.  This method gives us exactly that.
void RenderSVGRoot::buildLocalToBorderBoxTransform()
{
    SVGSVGElement* svg = toSVGSVGElement(node());
    ASSERT(svg);
    float scale = style()->effectiveZoom();
    FloatPoint translate = svg->currentTranslate();
    LayoutSize borderAndPadding(borderLeft() + paddingLeft(), borderTop() + paddingTop());
    m_localToBorderBoxTransform = svg->viewBoxToViewTransform(contentWidth() / scale, contentHeight() / scale);
    if (borderAndPadding.isEmpty() && scale == 1 && translate == FloatPoint::zero())
        return;
    m_localToBorderBoxTransform = AffineTransform(scale, 0, 0, scale, borderAndPadding.width() + translate.x(), borderAndPadding.height() + translate.y()) * m_localToBorderBoxTransform;
}

const AffineTransform& RenderSVGRoot::localToParentTransform() const
{
    // Slightly optimized version of m_localToParentTransform = AffineTransform::translation(x(), y()) * m_localToBorderBoxTransform;
    m_localToParentTransform = m_localToBorderBoxTransform;
    if (x())
        m_localToParentTransform.setE(m_localToParentTransform.e() + roundToInt(x()));
    if (y())
        m_localToParentTransform.setF(m_localToParentTransform.f() + roundToInt(y()));
    return m_localToParentTransform;
}

LayoutRect RenderSVGRoot::clippedOverflowRectForRepaint(const RenderLayerModelObject* repaintContainer) const
{
    return SVGRenderSupport::clippedOverflowRectForRepaint(this, repaintContainer);
}

void RenderSVGRoot::computeFloatRectForRepaint(const RenderLayerModelObject* repaintContainer, FloatRect& repaintRect, bool fixed) const
{
    // Apply our local transforms (except for x/y translation), then our shadow,
    // and then call RenderBox's method to handle all the normal CSS Box model bits
    repaintRect = m_localToBorderBoxTransform.mapRect(repaintRect);

    // Apply initial viewport clip - not affected by overflow settings
    repaintRect.intersect(pixelSnappedBorderBoxRect());

    LayoutRect rect = enclosingIntRect(repaintRect);
    RenderReplaced::computeRectForRepaint(repaintContainer, rect, fixed);
    repaintRect = rect;
}

// This method expects local CSS box coordinates.
// Callers with local SVG viewport coordinates should first apply the localToBorderBoxTransform
// to convert from SVG viewport coordinates to local CSS box coordinates.
void RenderSVGRoot::mapLocalToContainer(const RenderLayerModelObject* repaintContainer, TransformState& transformState, MapCoordinatesFlags mode, bool* wasFixed) const
{
    ASSERT(mode & ~IsFixed); // We should have no fixed content in the SVG rendering tree.
    ASSERT(mode & UseTransforms); // mapping a point through SVG w/o respecting trasnforms is useless.

    RenderReplaced::mapLocalToContainer(repaintContainer, transformState, mode | ApplyContainerFlip, wasFixed);
}

const RenderObject* RenderSVGRoot::pushMappingToContainer(const RenderLayerModelObject* ancestorToStopAt, RenderGeometryMap& geometryMap) const
{
    return RenderReplaced::pushMappingToContainer(ancestorToStopAt, geometryMap);
}

void RenderSVGRoot::updateCachedBoundaries()
{
    SVGRenderSupport::computeContainerBoundingBoxes(this, m_objectBoundingBox, m_objectBoundingBoxValid, m_strokeBoundingBox, m_repaintBoundingBox);
    SVGRenderSupport::intersectRepaintRectWithResources(this, m_repaintBoundingBox);
    m_repaintBoundingBox.inflate(borderAndPaddingWidth().toFloat());
}

bool RenderSVGRoot::nodeAtPoint(const HitTestRequest& request, HitTestResult& result, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset, HitTestAction hitTestAction)
{
    LayoutPoint pointInParent = locationInContainer.point() - toLayoutSize(accumulatedOffset);
    LayoutPoint pointInBorderBox = pointInParent - toLayoutSize(location());

    // Only test SVG content if the point is in our content box.
    // FIXME: This should be an intersection when rect-based hit tests are supported by nodeAtFloatPoint.
    if (contentBoxRect().contains(pointInBorderBox)) {
        FloatPoint localPoint = localToParentTransform().inverse().mapPoint(FloatPoint(pointInParent));

        for (RenderObject* child = lastChild(); child; child = child->previousSibling()) {
            // FIXME: nodeAtFloatPoint() doesn't handle rect-based hit tests yet.
            if (child->nodeAtFloatPoint(request, result, localPoint, hitTestAction)) {
                updateHitTestResult(result, pointInBorderBox);
                if (!result.addNodeToRectBasedTestResult(child->node(), request, locationInContainer))
                    return true;
            }
        }
    }

    // If we didn't early exit above, we've just hit the container <svg> element. Unlike SVG 1.1, 2nd Edition allows container elements to be hit.
    if (hitTestAction == HitTestBlockBackground && visibleToHitTestRequest(request)) {
        // Only return true here, if the last hit testing phase 'BlockBackground' is executed. If we'd return true in the 'Foreground' phase,
        // hit testing would stop immediately. For SVG only trees this doesn't matter. Though when we have a <foreignObject> subtree we need
        // to be able to detect hits on the background of a <div> element. If we'd return true here in the 'Foreground' phase, we are not able
        // to detect these hits anymore.
        LayoutRect boundsRect(accumulatedOffset + location(), size());
        if (locationInContainer.intersects(boundsRect)) {
            updateHitTestResult(result, pointInBorderBox);
            if (!result.addNodeToRectBasedTestResult(node(), request, locationInContainer, boundsRect))
                return true;
        }
    }

    return false;
}

bool RenderSVGRoot::hasRelativeIntrinsicLogicalWidth() const
{
    SVGSVGElement* svg = toSVGSVGElement(node());
    ASSERT(svg);
    return svg->intrinsicWidth(SVGSVGElement::IgnoreCSSProperties).isPercent();
}

bool RenderSVGRoot::hasRelativeLogicalHeight() const
{
    SVGSVGElement* svg = toSVGSVGElement(node());
    ASSERT(svg);

    return svg->intrinsicHeight(SVGSVGElement::IgnoreCSSProperties).isPercent();
}

}