SVGRenderSupport.cpp   [plain text]

/*
 * Copyright (C) 2007, 2008 Rob Buis <buis@kde.org>
 * Copyright (C) 2007 Nikolas Zimmermann <zimmermann@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>
 * Copyright (C) Research In Motion Limited 2009-2010. 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 "SVGRenderSupport.h"

#include "NodeRenderStyle.h"
#include "RenderElement.h"
#include "RenderGeometryMap.h"
#include "RenderIterator.h"
#include "RenderLayer.h"
#include "RenderSVGResourceClipper.h"
#include "RenderSVGResourceFilter.h"
#include "RenderSVGResourceMarker.h"
#include "RenderSVGResourceMasker.h"
#include "RenderSVGRoot.h"
#include "RenderSVGText.h"
#include "RenderSVGViewportContainer.h"
#include "SVGResources.h"
#include "SVGResourcesCache.h"
#include "TransformState.h"

namespace WebCore {

FloatRect SVGRenderSupport::repaintRectForRendererInLocalCoordinatesExcludingSVGShadow(const RenderElement& renderer)
{
    // FIXME: Add support for RenderSVGBlock.

    if (renderer.isSVGShape() || renderer.isSVGImage() || renderer.isSVGContainer())
        return toRenderSVGModelObject(renderer).repaintRectInLocalCoordinatesExcludingSVGShadow();

    return renderer.repaintRectInLocalCoordinates();
}

LayoutRect SVGRenderSupport::clippedOverflowRectForRepaint(const RenderElement& renderer, const RenderLayerModelObject* repaintContainer)
{
    // Return early for any cases where we don't actually paint
    if (renderer.style().visibility() != VISIBLE && !renderer.enclosingLayer()->hasVisibleContent())
        return LayoutRect();

    // Pass our local paint rect to computeRectForRepaint() which will
    // map to parent coords and recurse up the parent chain.
    FloatRect repaintRect = repaintRectForRendererInLocalCoordinatesExcludingSVGShadow(renderer);
    const SVGRenderStyle& svgStyle = renderer.style().svgStyle();
    if (const ShadowData* shadow = svgStyle.shadow())
        shadow->adjustRectForShadow(repaintRect);
    renderer.computeFloatRectForRepaint(repaintContainer, repaintRect);
    return enclosingLayoutRect(repaintRect);
}

void SVGRenderSupport::computeFloatRectForRepaint(const RenderElement& renderer, const RenderLayerModelObject* repaintContainer, FloatRect& repaintRect, bool fixed)
{
    const SVGRenderStyle& svgStyle = renderer.style().svgStyle();
    if (const ShadowData* shadow = svgStyle.shadow())
        shadow->adjustRectForShadow(repaintRect);
    repaintRect.inflate(renderer.style().outlineWidth());

    // Translate to coords in our parent renderer, and then call computeFloatRectForRepaint() on our parent.
    repaintRect = renderer.localToParentTransform().mapRect(repaintRect);
    renderer.parent()->computeFloatRectForRepaint(repaintContainer, repaintRect, fixed);
}

void SVGRenderSupport::mapLocalToContainer(const RenderElement& renderer, const RenderLayerModelObject* repaintContainer, TransformState& transformState, bool* wasFixed)
{
    ASSERT(renderer.parent());
    auto& parent = *renderer.parent();
    
    // At the SVG/HTML boundary (aka RenderSVGRoot), we apply the localToBorderBoxTransform 
    // to map an element from SVG viewport coordinates to CSS box coordinates.
    // RenderSVGRoot's mapLocalToContainer method expects CSS box coordinates.
    if (parent.isSVGRoot())
        transformState.applyTransform(toRenderSVGRoot(parent).localToBorderBoxTransform());

    transformState.applyTransform(renderer.localToParentTransform());

    MapCoordinatesFlags mode = UseTransforms;
    parent.mapLocalToContainer(repaintContainer, transformState, mode, wasFixed);
}

const RenderElement* SVGRenderSupport::pushMappingToContainer(const RenderElement& renderer, const RenderLayerModelObject* ancestorToStopAt, RenderGeometryMap& geometryMap)
{
    ASSERT_UNUSED(ancestorToStopAt, ancestorToStopAt != &renderer);

    ASSERT(renderer.parent());
    auto& parent = *renderer.parent();

    // At the SVG/HTML boundary (aka RenderSVGRoot), we apply the localToBorderBoxTransform 
    // to map an element from SVG viewport coordinates to CSS box coordinates.
    // RenderSVGRoot's mapLocalToContainer method expects CSS box coordinates.
    if (parent.isSVGRoot()) {
        TransformationMatrix matrix(renderer.localToParentTransform());
        matrix.multiply(toRenderSVGRoot(parent).localToBorderBoxTransform());
        geometryMap.push(&renderer, matrix);
    } else
        geometryMap.push(&renderer, renderer.localToParentTransform());

    return &parent;
}

bool SVGRenderSupport::checkForSVGRepaintDuringLayout(const RenderElement& renderer)
{
    if (!renderer.checkForRepaintDuringLayout())
        return false;
    // When a parent container is transformed in SVG, all children will be painted automatically
    // so we are able to skip redundant repaint checks.
    auto parent = renderer.parent();
    return !(parent && parent->isSVGContainer() && toRenderSVGContainer(parent)->didTransformToRootUpdate());
}

// Update a bounding box taking into account the validity of the other bounding box.
static inline void updateObjectBoundingBox(FloatRect& objectBoundingBox, bool& objectBoundingBoxValid, RenderObject* other, FloatRect otherBoundingBox)
{
    bool otherValid = other->isSVGContainer() ? toRenderSVGContainer(other)->isObjectBoundingBoxValid() : true;
    if (!otherValid)
        return;

    if (!objectBoundingBoxValid) {
        objectBoundingBox = otherBoundingBox;
        objectBoundingBoxValid = true;
        return;
    }

    objectBoundingBox.uniteEvenIfEmpty(otherBoundingBox);
}

void SVGRenderSupport::computeContainerBoundingBoxes(const RenderElement& container, FloatRect& objectBoundingBox, bool& objectBoundingBoxValid, FloatRect& strokeBoundingBox, FloatRect& repaintBoundingBox)
{
    objectBoundingBox = FloatRect();
    objectBoundingBoxValid = false;
    strokeBoundingBox = FloatRect();

    // When computing the strokeBoundingBox, we use the repaintRects of the container's children so that the container's stroke includes
    // the resources applied to the children (such as clips and filters). This allows filters applied to containers to correctly bound
    // the children, and also improves inlining of SVG content, as the stroke bound is used in that situation also.
    for (RenderObject* current = container.firstChild(); current; current = current->nextSibling()) {
        if (current->isSVGHiddenContainer())
            continue;

        // Don't include elements in the union that do not render.
        if (current->isSVGShape() && toRenderSVGShape(current)->isRenderingDisabled())
            continue;

        const AffineTransform& transform = current->localToParentTransform();
        if (transform.isIdentity()) {
            updateObjectBoundingBox(objectBoundingBox, objectBoundingBoxValid, current, current->objectBoundingBox());
            strokeBoundingBox.unite(current->repaintRectInLocalCoordinates());
        } else {
            updateObjectBoundingBox(objectBoundingBox, objectBoundingBoxValid, current, transform.mapRect(current->objectBoundingBox()));
            strokeBoundingBox.unite(transform.mapRect(current->repaintRectInLocalCoordinates()));
        }
    }

    repaintBoundingBox = strokeBoundingBox;
}

bool SVGRenderSupport::paintInfoIntersectsRepaintRect(const FloatRect& localRepaintRect, const AffineTransform& localTransform, const PaintInfo& paintInfo)
{
    if (localTransform.isIdentity())
        return localRepaintRect.intersects(paintInfo.rect);

    return localTransform.mapRect(localRepaintRect).intersects(paintInfo.rect);
}

const RenderSVGRoot& SVGRenderSupport::findTreeRootObject(const RenderElement& start)
{
    return *lineageOfType<RenderSVGRoot>(start).first();
}

static inline void invalidateResourcesOfChildren(RenderElement& renderer)
{
    ASSERT(!renderer.needsLayout());
    if (SVGResources* resources = SVGResourcesCache::cachedResourcesForRenderObject(renderer))
        resources->removeClientFromCache(renderer, false);

    for (auto& child : childrenOfType<RenderElement>(renderer))
        invalidateResourcesOfChildren(child);
}

static inline bool layoutSizeOfNearestViewportChanged(const RenderElement& renderer)
{
    const RenderElement* start = &renderer;
    while (start && !start->isSVGRoot() && !start->isSVGViewportContainer())
        start = start->parent();

    ASSERT(start);
    ASSERT(start->isSVGRoot() || start->isSVGViewportContainer());
    if (start->isSVGViewportContainer())
        return toRenderSVGViewportContainer(start)->isLayoutSizeChanged();

    return toRenderSVGRoot(start)->isLayoutSizeChanged();
}

bool SVGRenderSupport::transformToRootChanged(RenderElement* ancestor)
{
    while (ancestor && !ancestor->isSVGRoot()) {
        if (ancestor->isSVGTransformableContainer())
            return toRenderSVGContainer(ancestor)->didTransformToRootUpdate();
        if (ancestor->isSVGViewportContainer())
            return toRenderSVGViewportContainer(ancestor)->didTransformToRootUpdate();
        ancestor = ancestor->parent();
    }

    return false;
}

void SVGRenderSupport::layoutChildren(RenderElement& start, bool selfNeedsLayout)
{
    bool layoutSizeChanged = layoutSizeOfNearestViewportChanged(start);
    bool transformChanged = transformToRootChanged(&start);
    bool hasSVGShadow = rendererHasSVGShadow(start);
    bool needsBoundariesUpdate = start.needsBoundariesUpdate();
    HashSet<RenderElement*> elementsThatDidNotReceiveLayout;

    for (RenderObject* child = start.firstChild(); child; child = child->nextSibling()) {
        bool needsLayout = selfNeedsLayout;
        bool childEverHadLayout = child->everHadLayout();

        if (needsBoundariesUpdate && hasSVGShadow) {
            // If we have a shadow, our shadow is baked into our children's cached boundaries,
            // so they need to update.
            child->setNeedsBoundariesUpdate();
            needsLayout = true;
        }

        if (transformChanged) {
            // If the transform changed we need to update the text metrics (note: this also happens for layoutSizeChanged=true).
            if (child->isSVGText())
                toRenderSVGText(child)->setNeedsTextMetricsUpdate();
            needsLayout = true;
        }

        if (layoutSizeChanged) {
            // When selfNeedsLayout is false and the layout size changed, we have to check whether this child uses relative lengths
            if (SVGElement* element = child->node()->isSVGElement() ? toSVGElement(child->node()) : 0) {
                if (element->hasRelativeLengths()) {
                    // When the layout size changed and when using relative values tell the RenderSVGShape to update its shape object
                    if (child->isSVGShape())
                        toRenderSVGShape(child)->setNeedsShapeUpdate();
                    else if (child->isSVGText()) {
                        toRenderSVGText(child)->setNeedsTextMetricsUpdate();
                        toRenderSVGText(child)->setNeedsPositioningValuesUpdate();
                    }

                    needsLayout = true;
                }
            }
        }

        if (needsLayout)
            child->setNeedsLayout(MarkOnlyThis);

        if (child->needsLayout()) {
            toRenderElement(child)->layout();
            // Renderers are responsible for repainting themselves when changing, except
            // for the initial paint to avoid potential double-painting caused by non-sensical "old" bounds.
            // We could handle this in the individual objects, but for now it's easier to have
            // parent containers call repaint().  (RenderBlock::layout* has similar logic.)
            if (!childEverHadLayout)
                child->repaint();
        } else if (layoutSizeChanged && child->isRenderElement())
            elementsThatDidNotReceiveLayout.add(toRenderElement(child));

        ASSERT(!child->needsLayout());
    }

    if (!layoutSizeChanged) {
        ASSERT(elementsThatDidNotReceiveLayout.isEmpty());
        return;
    }

    // If the layout size changed, invalidate all resources of all children that didn't go through the layout() code path.
    for (auto* element : elementsThatDidNotReceiveLayout)
        invalidateResourcesOfChildren(*element);
}

bool SVGRenderSupport::isOverflowHidden(const RenderElement& renderer)
{
    // RenderSVGRoot should never query for overflow state - it should always clip itself to the initial viewport size.
    ASSERT(!renderer.isRoot());

    return renderer.style().overflowX() == OHIDDEN || renderer.style().overflowX() == OSCROLL;
}

bool SVGRenderSupport::rendererHasSVGShadow(const RenderObject& renderer)
{
    // FIXME: Add support for RenderSVGBlock.

    if (renderer.isSVGShape() || renderer.isSVGImage() || renderer.isSVGContainer())
        return toRenderSVGModelObject(renderer).hasSVGShadow();

    if (renderer.isSVGRoot())
        return toRenderSVGRoot(renderer).hasSVGShadow();

    return false;
}

void SVGRenderSupport::setRendererHasSVGShadow(RenderObject& renderer, bool hasShadow)
{
    // FIXME: Add support for RenderSVGBlock.

    if (renderer.isSVGShape() || renderer.isSVGImage() || renderer.isSVGContainer()) {
        toRenderSVGModelObject(renderer).setHasSVGShadow(hasShadow);
        return;
    }

    if (renderer.isSVGRoot())
        toRenderSVGRoot(renderer).setHasSVGShadow(hasShadow);
}

void SVGRenderSupport::intersectRepaintRectWithShadows(const RenderElement& renderer, FloatRect& repaintRect)
{
    // Since -webkit-svg-shadow enables shadow drawing for its children, but its children
    // don't inherit the shadow in their SVGRenderStyle, we need to search our parents for
    // shadows in order to correctly compute our repaint rect.

    auto currentObject = &renderer;

    AffineTransform localToRootTransform;

    while (currentObject && rendererHasSVGShadow(*currentObject)) {
        const RenderStyle& style = currentObject->style();
        const SVGRenderStyle& svgStyle = style.svgStyle();
        if (const ShadowData* shadow = svgStyle.shadow())
            shadow->adjustRectForShadow(repaintRect);

        repaintRect = currentObject->localToParentTransform().mapRect(repaintRect);
        localToRootTransform *= currentObject->localToParentTransform();

        currentObject = currentObject->parent();
    };

    if (localToRootTransform.isIdentity())
        return;

    AffineTransform rootToLocalTransform = localToRootTransform.inverse();
    repaintRect = rootToLocalTransform.mapRect(repaintRect);
}

void SVGRenderSupport::intersectRepaintRectWithResources(const RenderElement& renderer, FloatRect& repaintRect)
{
    SVGResources* resources = SVGResourcesCache::cachedResourcesForRenderObject(renderer);
    if (!resources)
        return;

#if ENABLE(FILTERS)
    if (RenderSVGResourceFilter* filter = resources->filter())
        repaintRect = filter->resourceBoundingBox(renderer);
#endif

    if (RenderSVGResourceClipper* clipper = resources->clipper())
        repaintRect.intersect(clipper->resourceBoundingBox(renderer));

    if (RenderSVGResourceMasker* masker = resources->masker())
        repaintRect.intersect(masker->resourceBoundingBox(renderer));
}

bool SVGRenderSupport::filtersForceContainerLayout(const RenderElement& renderer)
{
    // If any of this container's children need to be laid out, and a filter is applied
    // to the container, we need to repaint the entire container.
    if (!renderer.normalChildNeedsLayout())
        return false;

    SVGResources* resources = SVGResourcesCache::cachedResourcesForRenderObject(renderer);
    if (!resources || !resources->filter())
        return false;

    return true;
}

bool SVGRenderSupport::pointInClippingArea(const RenderElement& renderer, const FloatPoint& point)
{
    // We just take clippers into account to determine if a point is on the node. The Specification may
    // change later and we also need to check maskers.
    SVGResources* resources = SVGResourcesCache::cachedResourcesForRenderObject(renderer);
    if (!resources)
        return true;

    if (RenderSVGResourceClipper* clipper = resources->clipper())
        return clipper->hitTestClipContent(renderer.objectBoundingBox(), point);

    return true;
}

void SVGRenderSupport::applyStrokeStyleToContext(GraphicsContext* context, const RenderStyle& style, const RenderElement& renderer)
{
    ASSERT(context);
    ASSERT(renderer.element());
    ASSERT(renderer.element()->isSVGElement());

    const SVGRenderStyle& svgStyle = style.svgStyle();

    SVGLengthContext lengthContext(toSVGElement(renderer.element()));
    context->setStrokeThickness(svgStyle.strokeWidth().value(lengthContext));
    context->setLineCap(svgStyle.capStyle());
    context->setLineJoin(svgStyle.joinStyle());
    if (svgStyle.joinStyle() == MiterJoin)
        context->setMiterLimit(svgStyle.strokeMiterLimit());

    const Vector<SVGLength>& dashes = svgStyle.strokeDashArray();
    if (dashes.isEmpty())
        context->setStrokeStyle(SolidStroke);
    else {
        DashArray dashArray;
        dashArray.reserveInitialCapacity(dashes.size());
        for (auto& dash : dashes)
            dashArray.uncheckedAppend(dash.value(lengthContext));

        context->setLineDash(dashArray, svgStyle.strokeDashOffset().value(lengthContext));
    }
}

void SVGRenderSupport::childAdded(RenderElement& parent, RenderObject& child)
{
    SVGRenderSupport::setRendererHasSVGShadow(child, SVGRenderSupport::rendererHasSVGShadow(parent) || SVGRenderSupport::rendererHasSVGShadow(child));
}

void SVGRenderSupport::styleChanged(RenderElement& renderer, const RenderStyle* oldStyle)
{
    auto parent = renderer.parent();
    SVGRenderSupport::setRendererHasSVGShadow(renderer, (parent && SVGRenderSupport::rendererHasSVGShadow(*parent)) || renderer.style().svgStyle().shadow());

#if ENABLE(CSS_COMPOSITING)
    if (renderer.element() && renderer.element()->isSVGElement() && (!oldStyle || renderer.style().hasBlendMode() != oldStyle->hasBlendMode()))
        SVGRenderSupport::updateMaskedAncestorShouldIsolateBlending(renderer);
#else
    UNUSED_PARAM(oldStyle);
#endif
}

#if ENABLE(CSS_COMPOSITING)
bool SVGRenderSupport::isolatesBlending(const RenderStyle& style)
{
    return style.svgStyle().isolatesBlending() || style.hasBlendMode() || style.opacity() < 1.0f;
}

void SVGRenderSupport::updateMaskedAncestorShouldIsolateBlending(const RenderElement& renderer)
{
    ASSERT(renderer.element());
    ASSERT(renderer.element()->isSVGElement());

    bool maskedAncestorShouldIsolateBlending = renderer.style().hasBlendMode();
    for (auto* ancestor = renderer.element()->parentElement(); ancestor && ancestor->isSVGElement(); ancestor = ancestor->parentElement()) {
        if (!toSVGElement(ancestor)->isSVGGraphicsElement() || !isolatesBlending(*ancestor->computedStyle()))
            continue;

        if (ancestor->computedStyle()->svgStyle().hasMasker())
            toSVGGraphicsElement(ancestor)->setShouldIsolateBlending(maskedAncestorShouldIsolateBlending);

        return;
    }
}
#endif
}