Source/WebCore/rendering/svg/SVGRenderSupport.cpp

/*
 * 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"

#if ENABLE(SVG)
#include "SVGRenderSupport.h"

#include "NodeRenderStyle.h"
#include "RenderGeometryMap.h"
#include "RenderLayer.h"
#include "RenderSVGResource.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 "SVGStyledElement.h"
#include "TransformState.h"
#include <wtf/UnusedParam.h>

namespace WebCore {

LayoutRect SVGRenderSupport::clippedOverflowRectForRepaint(const RenderObject* object, RenderBoxModelObject* 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, RenderBoxModelObject* repaintContainer, FloatRect& repaintRect, bool fixed)
{
    const SVGRenderStyle* svgStyle = object->style()->svgStyle();
    if (const ShadowData* shadow = svgStyle->shadow())
        shadow->adjustRectForShadow(repaintRect);
    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, RenderBoxModelObject* repaintContainer, TransformState& transformState, bool snapOffsetForTransforms, 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());

    MapLocalToContainerFlags mode = UseTransforms;
    if (snapOffsetForTransforms)
        mode |= SnapOffsetForTransforms;
    parent->mapLocalToContainer(repaintContainer, transformState, mode, wasFixed);
}

const RenderObject* SVGRenderSupport::pushMappingToContainer(const RenderObject* object, const RenderBoxModelObject* 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())
        geometryMap.push(object, TransformationMatrix(toRenderSVGRoot(parent)->localToBorderBoxTransform()));
    else
        geometryMap.push(object, LayoutSize());

    return parent;
}

// 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();
        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 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() ? static_cast<SVGElement*>(child->node()) : 0) {
                if (element->isStyled() && static_cast<SVGStyledElement*>(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(true, MarkOnlyThis);

        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)
                child->repaint();
        } else if (layoutSizeChanged)
            notlayoutedObjects.add(child);

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

    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);
}

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* object, FloatRect& repaintRect)
{
    ASSERT(object);

    RenderStyle* style = object->style();
    ASSERT(style);

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

    RenderObject* renderer = const_cast<RenderObject*>(object);
    SVGResources* resources = SVGResourcesCache::cachedResourcesForRenderObject(renderer);
    if (!resources) {
        if (const ShadowData* shadow = svgStyle->shadow())
            shadow->adjustRectForShadow(repaintRect);
        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));

    if (const ShadowData* shadow = svgStyle->shadow())
        shadow->adjustRectForShadow(repaintRect);
}

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(static_cast<SVGElement*>(object->node()));
    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;
        const Vector<SVGLength>::const_iterator end = dashes.end();
        for (Vector<SVGLength>::const_iterator it = dashes.begin(); it != end; ++it)
            dashArray.append((*it).value(lengthContext));

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

}

#endif