third_party/WebKit/Source/core/layout/svg/LayoutSVGContainer.cpp

/*
 * Copyright (C) 2004, 2005, 2007 Nikolas Zimmermann <zimmermann@kde.org>
 * Copyright (C) 2004, 2005, 2007, 2008 Rob Buis <buis@kde.org>
 * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
 * Copyright (C) 2009 Google, Inc.  All rights reserved.
 * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
 *
 * 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 "core/layout/svg/LayoutSVGContainer.h"

#include "core/layout/HitTestResult.h"
#include "core/layout/LayoutAnalyzer.h"
#include "core/layout/svg/SVGLayoutSupport.h"
#include "core/layout/svg/SVGResources.h"
#include "core/layout/svg/SVGResourcesCache.h"
#include "core/paint/SVGContainerPainter.h"

namespace blink {

LayoutSVGContainer::LayoutSVGContainer(SVGElement* node)
    : LayoutSVGModelObject(node)
    , m_objectBoundingBoxValid(false)
    , m_needsBoundariesUpdate(true)
    , m_didScreenScaleFactorChange(false)
    , m_hasNonIsolatedBlendingDescendants(false)
    , m_hasNonIsolatedBlendingDescendantsDirty(false)
{
}

LayoutSVGContainer::~LayoutSVGContainer()
{
}

void LayoutSVGContainer::layout()
{
    ASSERT(needsLayout());
    LayoutAnalyzer::Scope analyzer(*this);

    // Allow LayoutSVGViewportContainer to update its viewport.
    calcViewport();

    // Allow LayoutSVGTransformableContainer to update its transform.
    SVGTransformChange transformChange = calculateLocalTransform();
    m_didScreenScaleFactorChange =
        transformChange == SVGTransformChange::Full || SVGLayoutSupport::screenScaleFactorChanged(parent());

    // LayoutSVGViewportContainer needs to set the 'layout size changed' flag.
    determineIfLayoutSizeChanged();

    // When hasRelativeLengths() is false, no descendants have relative lengths
    // (hence no one is interested in viewport size changes).
    bool layoutSizeChanged = element()->hasRelativeLengths()
        && SVGLayoutSupport::layoutSizeOfNearestViewportChanged(this);

    SVGLayoutSupport::layoutChildren(firstChild(), false, m_didScreenScaleFactorChange, layoutSizeChanged);

    // Invalidate all resources of this client if our layout changed.
    if (everHadLayout() && needsLayout())
        SVGResourcesCache::clientLayoutChanged(this);

    if (m_needsBoundariesUpdate || transformChange != SVGTransformChange::None) {
        updateCachedBoundaries();
        m_needsBoundariesUpdate = false;

        // If our bounds changed, notify the parents.
        LayoutSVGModelObject::setNeedsBoundariesUpdate();
    }

    ASSERT(!m_needsBoundariesUpdate);
    clearNeedsLayout();
}

void LayoutSVGContainer::addChild(LayoutObject* child, LayoutObject* beforeChild)
{
    LayoutSVGModelObject::addChild(child, beforeChild);
    SVGResourcesCache::clientWasAddedToTree(child, child->styleRef());

    bool shouldIsolateDescendants = (child->isBlendingAllowed() && child->style()->hasBlendMode()) || child->hasNonIsolatedBlendingDescendants();
    if (shouldIsolateDescendants)
        descendantIsolationRequirementsChanged(DescendantIsolationRequired);
}

void LayoutSVGContainer::removeChild(LayoutObject* child)
{
    SVGResourcesCache::clientWillBeRemovedFromTree(child);
    LayoutSVGModelObject::removeChild(child);

    bool hadNonIsolatedDescendants = (child->isBlendingAllowed() && child->style()->hasBlendMode()) || child->hasNonIsolatedBlendingDescendants();
    if (hadNonIsolatedDescendants)
        descendantIsolationRequirementsChanged(DescendantIsolationNeedsUpdate);
}

bool LayoutSVGContainer::selfWillPaint() const
{
    return SVGLayoutSupport::hasFilterResource(*this);
}

void LayoutSVGContainer::styleDidChange(StyleDifference diff, const ComputedStyle* oldStyle)
{
    LayoutSVGModelObject::styleDidChange(diff, oldStyle);

    bool hadIsolation = oldStyle && !isSVGHiddenContainer() && SVGLayoutSupport::willIsolateBlendingDescendantsForStyle(*oldStyle);
    bool isolationChanged = hadIsolation == !SVGLayoutSupport::willIsolateBlendingDescendantsForObject(this);

    if (!parent() || !isolationChanged)
        return;

    if (hasNonIsolatedBlendingDescendants())
        parent()->descendantIsolationRequirementsChanged(SVGLayoutSupport::willIsolateBlendingDescendantsForObject(this) ? DescendantIsolationNeedsUpdate : DescendantIsolationRequired);
}

bool LayoutSVGContainer::hasNonIsolatedBlendingDescendants() const
{
    if (m_hasNonIsolatedBlendingDescendantsDirty) {
        m_hasNonIsolatedBlendingDescendants = SVGLayoutSupport::computeHasNonIsolatedBlendingDescendants(this);
        m_hasNonIsolatedBlendingDescendantsDirty = false;
    }
    return m_hasNonIsolatedBlendingDescendants;
}

void LayoutSVGContainer::descendantIsolationRequirementsChanged(DescendantIsolationState state)
{
    switch (state) {
    case DescendantIsolationRequired:
        m_hasNonIsolatedBlendingDescendants = true;
        m_hasNonIsolatedBlendingDescendantsDirty = false;
        break;
    case DescendantIsolationNeedsUpdate:
        if (m_hasNonIsolatedBlendingDescendantsDirty)
            return;
        m_hasNonIsolatedBlendingDescendantsDirty = true;
        break;
    }
    if (SVGLayoutSupport::willIsolateBlendingDescendantsForObject(this))
        return;
    if (parent())
        parent()->descendantIsolationRequirementsChanged(state);
}

void LayoutSVGContainer::paint(const PaintInfo& paintInfo, const LayoutPoint&) const
{
    SVGContainerPainter(*this).paint(paintInfo);
}

void LayoutSVGContainer::addOutlineRects(Vector<LayoutRect>& rects, const LayoutPoint&, IncludeBlockVisualOverflowOrNot) const
{
    rects.append(LayoutRect(paintInvalidationRectInLocalSVGCoordinates()));
}

void LayoutSVGContainer::updateCachedBoundaries()
{
    SVGLayoutSupport::computeContainerBoundingBoxes(this, m_objectBoundingBox, m_objectBoundingBoxValid, m_strokeBoundingBox, m_paintInvalidationBoundingBox);
    SVGLayoutSupport::intersectPaintInvalidationRectWithResources(this, m_paintInvalidationBoundingBox);
    if (element())
        element()->setNeedsResizeObserverUpdate();
}

bool LayoutSVGContainer::nodeAtFloatPoint(HitTestResult& result, const FloatPoint& pointInParent, HitTestAction hitTestAction)
{
    // Give LayoutSVGViewportContainer a chance to apply its viewport clip
    if (!pointIsInsideViewportClip(pointInParent))
        return false;

    FloatPoint localPoint;
    if (!SVGLayoutSupport::transformToUserSpaceAndCheckClipping(this, localToSVGParentTransform(), pointInParent, localPoint))
        return false;

    for (LayoutObject* child = lastChild(); child; child = child->previousSibling()) {
        if (child->nodeAtFloatPoint(result, localPoint, hitTestAction)) {
            const LayoutPoint& localLayoutPoint = roundedLayoutPoint(localPoint);
            updateHitTestResult(result, localLayoutPoint);
            if (result.addNodeToListBasedTestResult(child->node(), localLayoutPoint) == StopHitTesting)
                return true;
        }
    }

    // pointer-events: bounding-box makes it possible for containers to be direct targets.
    if (style()->pointerEvents() == PE_BOUNDINGBOX) {
        // Check for a valid bounding box because it will be invalid for empty containers.
        if (isObjectBoundingBoxValid() && objectBoundingBox().contains(localPoint)) {
            const LayoutPoint& localLayoutPoint = roundedLayoutPoint(localPoint);
            updateHitTestResult(result, localLayoutPoint);
            if (result.addNodeToListBasedTestResult(element(), localLayoutPoint) == StopHitTesting)
                return true;
        }
    }
    // 16.4: "If there are no graphics elements whose relevant graphics content is under the pointer (i.e., there is no target element), the event is not dispatched."
    return false;
}

SVGTransformChange LayoutSVGContainer::calculateLocalTransform()
{
    return SVGTransformChange::None;
}

} // namespace blink