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

DEFINITIONS

1. clippedOverflowRectForRepaint
2. computeFloatRectForRepaint
3. mapLocalToContainer
4. pushMappingToContainer
5. checkForSVGRepaintDuringLayout
6. updateObjectBoundingBox
7. computeContainerBoundingBoxes
8. paintInfoIntersectsRepaintRect
9. findTreeRootObject
10. invalidateResourcesOfChildren
11. layoutSizeOfNearestViewportChanged
12. transformToRootChanged
13. layoutChildren
14. layoutResourcesIfNeeded
15. isOverflowHidden
16. intersectRepaintRectWithResources
17. filtersForceContainerLayout
18. pointInClippingArea
19. applyStrokeStyleToContext
20. applyStrokeStyleToStrokeData
21. isRenderableTextNode

/*
 * 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 "core/rendering/svg/SVGRenderSupport.h"

#include "core/rendering/RenderGeometryMap.h"
#include "core/rendering/RenderLayer.h"
#include "core/rendering/SubtreeLayoutScope.h"
#include "core/rendering/svg/RenderSVGInlineText.h"
#include "core/rendering/svg/RenderSVGResourceClipper.h"
#include "core/rendering/svg/RenderSVGResourceFilter.h"
#include "core/rendering/svg/RenderSVGResourceMasker.h"
#include "core/rendering/svg/RenderSVGRoot.h"
#include "core/rendering/svg/RenderSVGText.h"
#include "core/rendering/svg/RenderSVGViewportContainer.h"
#include "core/rendering/svg/SVGResources.h"
#include "core/rendering/svg/SVGResourcesCache.h"
#include "core/svg/SVGElement.h"
#include "platform/geometry/TransformState.h"

namespace WebCore {

LayoutRect SVGRenderSupport::clippedOverflowRectForRepaint(const RenderObject* object, const RenderLayerModelObject* repaintContainer)
{
    // Return early for any cases where we don't actually paint
    if (object->style()->visibility() != VISIBLE && !object->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 = object->repaintRectInLocalCoordinates();
    object->computeFloatRectForRepaint(repaintContainer, repaintRect);
    return enclosingLayoutRect(repaintRect);
}

void SVGRenderSupport::computeFloatRectForRepaint(const RenderObject* object, const RenderLayerModelObject* repaintContainer, FloatRect& repaintRect, bool fixed)
{
    repaintRect.inflate(object->style()->outlineWidth());

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

void SVGRenderSupport::mapLocalToContainer(const RenderObject* object, const RenderLayerModelObject* repaintContainer, TransformState& transformState, bool* wasFixed)
{
    transformState.applyTransform(object->localToParentTransform());

    RenderObject* parent = object->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());

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

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

    RenderObject* parent = object->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(object->localToParentTransform());
        matrix.multiply(toRenderSVGRoot(parent)->localToBorderBoxTransform());
        geometryMap.push(object, matrix);
    } else
        geometryMap.push(object, object->localToParentTransform());

    return parent;
}

bool SVGRenderSupport::checkForSVGRepaintDuringLayout(RenderObject* object)
{
    if (!object->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.
    RenderObject* parent = object->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 RenderObject* 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;

        const AffineTransform& transform = current->localToParentTransform();
        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)
{
    return localTransform.mapRect(localRepaintRect).intersects(paintInfo.rect);
}

const RenderSVGRoot* SVGRenderSupport::findTreeRootObject(const RenderObject* start)
{
    while (start && !start->isSVGRoot())
        start = start->parent();

    ASSERT(start);
    ASSERT(start->isSVGRoot());
    return toRenderSVGRoot(start);
}

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

    for (RenderObject* child = start->firstChild(); child; child = child->nextSibling())
        invalidateResourcesOfChildren(child);
}

static inline bool layoutSizeOfNearestViewportChanged(const RenderObject* start)
{
    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(RenderObject* 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(RenderObject* start, bool selfNeedsLayout)
{
    bool layoutSizeChanged = layoutSizeOfNearestViewportChanged(start);
    bool transformChanged = transformToRootChanged(start);
    HashSet<RenderObject*> notlayoutedObjects;

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

        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;
                }
            }
        }

        SubtreeLayoutScope layoutScope(child);
        // Resource containers are nasty: they can invalidate clients outside the current SubtreeLayoutScope.
        // Since they only care about viewport size changes (to resolve their relative lengths), we trigger
        // their invalidation directly from SVGSVGElement::svgAttributeChange() or at a higher
        // SubtreeLayoutScope (in RenderView::layout()).
        if (needsLayout && !child->isSVGResourceContainer())
            layoutScope.setNeedsLayout(child);

        layoutResourcesIfNeeded(child);

        if (child->needsLayout()) {
            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 && !RuntimeEnabledFeatures::repaintAfterLayoutEnabled())
                child->repaint();
        } else if (layoutSizeChanged)
            notlayoutedObjects.add(child);
    }

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

    // If the layout size changed, invalidate all resources of all children that didn't go through the layout() code path.
    HashSet<RenderObject*>::iterator end = notlayoutedObjects.end();
    for (HashSet<RenderObject*>::iterator it = notlayoutedObjects.begin(); it != end; ++it)
        invalidateResourcesOfChildren(*it);
}

void SVGRenderSupport::layoutResourcesIfNeeded(const RenderObject* object)
{
    ASSERT(object);

    SVGResources* resources = SVGResourcesCache::cachedResourcesForRenderObject(object);
    if (resources)
        resources->layoutIfNeeded();
}

bool SVGRenderSupport::isOverflowHidden(const RenderObject* object)
{
    // SVG doesn't support independent x/y overflow
    ASSERT(object->style()->overflowX() == object->style()->overflowY());

    // OSCROLL is never set for SVG - see StyleResolver::adjustRenderStyle
    ASSERT(object->style()->overflowX() != OSCROLL);

    // RenderSVGRoot should never query for overflow state - it should always clip itself to the initial viewport size.
    ASSERT(!object->isRoot());

    return object->style()->overflowX() == OHIDDEN;
}

void SVGRenderSupport::intersectRepaintRectWithResources(const RenderObject* renderer, FloatRect& repaintRect)
{
    ASSERT(renderer);

    SVGResources* resources = SVGResourcesCache::cachedResourcesForRenderObject(renderer);
    if (!resources)
        return;

    if (RenderSVGResourceFilter* filter = resources->filter())
        repaintRect = filter->resourceBoundingBox(renderer);

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

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

bool SVGRenderSupport::filtersForceContainerLayout(RenderObject* object)
{
    // 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 (!object->normalChildNeedsLayout())
        return false;

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

    return true;
}

bool SVGRenderSupport::pointInClippingArea(RenderObject* object, const FloatPoint& point)
{
    ASSERT(object);

    // 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(object);
    if (!resources)
        return true;

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

    return true;
}

void SVGRenderSupport::applyStrokeStyleToContext(GraphicsContext* context, const RenderStyle* style, const RenderObject* object)
{
    ASSERT(context);
    ASSERT(style);
    ASSERT(object);
    ASSERT(object->node());
    ASSERT(object->node()->isSVGElement());

    const SVGRenderStyle* svgStyle = style->svgStyle();
    ASSERT(svgStyle);

    SVGLengthContext lengthContext(toSVGElement(object->node()));
    context->setStrokeThickness(svgStyle->strokeWidth()->value(lengthContext));
    context->setLineCap(svgStyle->capStyle());
    context->setLineJoin(svgStyle->joinStyle());
    context->setMiterLimit(svgStyle->strokeMiterLimit());

    RefPtr<SVGLengthList> dashes = svgStyle->strokeDashArray();
    if (dashes->isEmpty())
        return;

    DashArray dashArray;
    SVGLengthList::ConstIterator it = dashes->begin();
    SVGLengthList::ConstIterator itEnd = dashes->end();
    for (; it != itEnd; ++it)
        dashArray.append(it->value(lengthContext));

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

void SVGRenderSupport::applyStrokeStyleToStrokeData(StrokeData* strokeData, const RenderStyle* style, const RenderObject* object)
{
    ASSERT(strokeData);
    ASSERT(style);
    ASSERT(object);
    ASSERT(object->node());
    ASSERT(object->node()->isSVGElement());

    const SVGRenderStyle* svgStyle = style->svgStyle();
    ASSERT(svgStyle);

    SVGLengthContext lengthContext(toSVGElement(object->node()));
    strokeData->setThickness(svgStyle->strokeWidth()->value(lengthContext));
    strokeData->setLineCap(svgStyle->capStyle());
    strokeData->setLineJoin(svgStyle->joinStyle());
    strokeData->setMiterLimit(svgStyle->strokeMiterLimit());

    RefPtr<SVGLengthList> dashes = svgStyle->strokeDashArray();
    if (dashes->isEmpty())
        return;

    DashArray dashArray;
    size_t length = dashes->length();
    for (size_t i = 0; i < length; ++i)
        dashArray.append(dashes->at(i)->value(lengthContext));

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

bool SVGRenderSupport::isRenderableTextNode(const RenderObject* object)
{
    ASSERT(object->isText());
    // <br> is marked as text, but is not handled by the SVG rendering code-path.
    return object->isSVGInlineText() && !toRenderSVGInlineText(object)->hasEmptyText();
}

}