/*

 * Copyright (C) 2004, 2005, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>

 *               2004, 2005, 2006, 2007, 2008 Rob Buis <buis@kde.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 "RenderSVGResourceClipper.h"

#include "AffineTransform.h"

#include "FloatRect.h"

#include "GraphicsContext.h"

#include "HitTestRequest.h"

#include "HitTestResult.h"

#include "ImageBuffer.h"

#include "IntRect.h"

#include "RenderObject.h"

#include "RenderStyle.h"

#include "RenderSVGResource.h"

#include "SVGClipPathElement.h"

#include "SVGElement.h"

#include "SVGRenderSupport.h"

#include "SVGStyledElement.h"

#include "SVGStyledTransformableElement.h"

#include "SVGUnitTypes.h"

#include "SVGUseElement.h"

#include <wtf/UnusedParam.h>

namespace WebCore {

RenderSVGResourceType RenderSVGResourceClipper::s_resourceType = ClipperResourceType;

RenderSVGResourceClipper::RenderSVGResourceClipper(SVGClipPathElement* node)

    : RenderSVGResourceContainer(node)

    , m_invalidationBlocked(false)

{

}

RenderSVGResourceClipper::~RenderSVGResourceClipper()

{

    deleteAllValues(m_clipper);

    m_clipper.clear();

}

void RenderSVGResourceClipper::invalidateClients()

{

    if (m_invalidationBlocked)

        return;

    HashMap<RenderObject*, ClipperData*>::const_iterator end = m_clipper.end();

    for (HashMap<RenderObject*, ClipperData*>::const_iterator it = m_clipper.begin(); it != end; ++it)

        markForLayoutAndResourceInvalidation(it->first);

    deleteAllValues(m_clipper);

    m_clipper.clear();

    m_clipBoundaries = FloatRect();

}

void RenderSVGResourceClipper::invalidateClient(RenderObject* object)

{

    if (m_invalidationBlocked)

        return;

    ASSERT(object);

    if (!m_clipper.contains(object))

        return;

    delete m_clipper.take(object);

    markForLayoutAndResourceInvalidation(object);

}

bool RenderSVGResourceClipper::applyResource(RenderObject* object, RenderStyle*, GraphicsContext*& context, unsigned short resourceMode)

{

    ASSERT(object);

    ASSERT(context);

#ifndef NDEBUG

    ASSERT(resourceMode == ApplyToDefaultMode);

#else

    UNUSED_PARAM(resourceMode);

#endif

    // Early exit, if this resource contains a child which references ourselves.

    if (containsCyclicReference(node()))

        return false;

    applyClippingToContext(object, object->objectBoundingBox(), object->repaintRectInLocalCoordinates(), context);

    return true;

}

bool RenderSVGResourceClipper::pathOnlyClipping(GraphicsContext* context, const FloatRect& objectBoundingBox)

{

    // If the current clip-path gets clipped itself, we have to fallback to masking.

    if (!style()->svgStyle()->clipperResource().isEmpty())

        return false;

    WindRule clipRule = RULE_NONZERO;

    Path clipPath = Path();

    // If clip-path only contains one visible shape or path, we can use path-based clipping. Invisible

    // shapes don't affect the clipping and can be ignored. If clip-path contains more than one

    // visible shape, the additive clipping may not work, caused by the clipRule. EvenOdd

    // as well as NonZero can cause self-clipping of the elements.

    // See also http://www.w3.org/TR/SVG/painting.html#FillRuleProperty

    for (Node* childNode = node()->firstChild(); childNode; childNode = childNode->nextSibling()) {

        RenderObject* renderer = childNode->renderer();

        if (!renderer)

            continue;

        // Only shapes or paths are supported for direct clipping. We need to fallback to masking for texts.

        if (renderer->isSVGText())

            return false;

        if (!childNode->isSVGElement() || !static_cast<SVGElement*>(childNode)->isStyledTransformable())

            continue;

        SVGStyledTransformableElement* styled = static_cast<SVGStyledTransformableElement*>(childNode);

        RenderStyle* style = renderer->style();

        if (!style || style->display() == NONE || style->visibility() != VISIBLE)

             continue;

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

        // Current shape in clip-path gets clipped too. Fallback to masking.

        if (!svgStyle->clipperResource().isEmpty())

            return false;

        // Fallback to masking, if there is more than one clipping path.

        if (clipPath.isEmpty()) {

            clipPath = styled->toClipPath();

            clipRule = svgStyle->clipRule();

        } else

            return false;

    }

    // Only one visible shape/path was found. Directly continue clipping and transform the content to userspace if necessary.

    if (static_cast<SVGClipPathElement*>(node())->clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {

        AffineTransform transform;

        transform.translate(objectBoundingBox.x(), objectBoundingBox.y());

        transform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());

        clipPath.transform(transform);

    }

    // The SVG specification wants us to clip everything, if clip-path doesn't have a child.

    if (clipPath.isEmpty())

        clipPath.addRect(FloatRect());

    context->beginPath();

    context->addPath(clipPath);

    context->clipPath(clipRule);

    return true;

}

bool RenderSVGResourceClipper::applyClippingToContext(RenderObject* object, const FloatRect& objectBoundingBox,

                                                      const FloatRect& repaintRect, GraphicsContext* context)

{

    if (!m_clipper.contains(object))

        m_clipper.set(object, new ClipperData);

    ClipperData* clipperData = m_clipper.get(object);

    if (!clipperData->clipMaskImage) {

        if (pathOnlyClipping(context, objectBoundingBox))

            return true;

        createClipData(clipperData, objectBoundingBox, repaintRect);

    }

    if (!clipperData->clipMaskImage)

        return false;

    context->clipToImageBuffer(repaintRect, clipperData->clipMaskImage.get());

    return true;

}

bool RenderSVGResourceClipper::createClipData(ClipperData* clipperData, const FloatRect& objectBoundingBox, const FloatRect& repaintRect)

{

    IntRect clipMaskRect = enclosingIntRect(repaintRect);

    clipperData->clipMaskImage = ImageBuffer::create(clipMaskRect.size());

    if (!clipperData->clipMaskImage)

        return false;

    GraphicsContext* maskContext = clipperData->clipMaskImage->context();

    ASSERT(maskContext);

    maskContext->save();

    maskContext->translate(-repaintRect.x(), -repaintRect.y());

    // clipPath can also be clipped by another clipPath.

    if (RenderSVGResourceClipper* clipper = getRenderSVGResourceById<RenderSVGResourceClipper>(this->document(), style()->svgStyle()->clipperResource())) {

        if (!clipper->applyClippingToContext(this, objectBoundingBox, repaintRect, maskContext)) {

            maskContext->restore();

            return false;

        }            

    }

    SVGClipPathElement* clipPath = static_cast<SVGClipPathElement*>(node());

    if (clipPath->clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {

        maskContext->translate(objectBoundingBox.x(), objectBoundingBox.y());

        maskContext->scale(objectBoundingBox.size());

    }

    // Draw all clipPath children into a global mask.

    for (Node* childNode = node()->firstChild(); childNode; childNode = childNode->nextSibling()) {

        RenderObject* renderer = childNode->renderer();

        if (!childNode->isSVGElement() || !static_cast<SVGElement*>(childNode)->isStyled() || !renderer)

            continue;

        RenderStyle* style = renderer->style();

        if (!style || style->display() == NONE || style->visibility() != VISIBLE)

            continue;

        WindRule newClipRule = style->svgStyle()->clipRule();

        bool isUseElement = renderer->isSVGShadowTreeRootContainer();

        if (isUseElement) {

            SVGUseElement* useElement = static_cast<SVGUseElement*>(childNode);

            renderer = useElement->rendererClipChild();

            if (!renderer)

                continue;

            if (!useElement->hasAttribute(SVGNames::clip_ruleAttr))

                newClipRule = renderer->style()->svgStyle()->clipRule();

        }

        // Only shapes, paths and texts are allowed for clipping.

        if (!renderer->isRenderPath() && !renderer->isSVGText())

            continue;

        // Save the old RenderStyle of the current object for restoring after drawing

        // it to the MaskImage. The new intermediate RenderStyle needs to inherit from

        // the old one.

        RefPtr<RenderStyle> oldRenderStyle = renderer->style();

        RefPtr<RenderStyle> newRenderStyle = RenderStyle::clone(oldRenderStyle.get());

        SVGRenderStyle* svgStyle = newRenderStyle.get()->accessSVGStyle();

        svgStyle->setFillPaint(SVGPaint::defaultFill());

        svgStyle->setStrokePaint(SVGPaint::defaultStroke());

        svgStyle->setFillRule(newClipRule);

        newRenderStyle.get()->setOpacity(1.0f);

        svgStyle->setFillOpacity(1.0f);

        svgStyle->setStrokeOpacity(1.0f);

        svgStyle->setFilterResource(String());

        svgStyle->setMaskerResource(String());

        // The setStyle() call results in a styleDidChange() call, which in turn invalidations the resources.

        // As we're mutating the resource on purpose, block updates until we've resetted the style again.

        m_invalidationBlocked = true;

        renderer->setStyle(newRenderStyle.release());

        // In the case of a <use> element, we obtained its renderere above, to retrieve its clipRule.

        // We hsve to pass the <use> renderer itself to renderSubtreeToImage() to apply it's x/y/transform/etc. values when rendering.

        // So if isUseElement is true, refetch the childNode->renderer(), as renderer got overriden above.

        SVGRenderSupport::renderSubtreeToImage(clipperData->clipMaskImage.get(), isUseElement ? childNode->renderer() : renderer);

        renderer->setStyle(oldRenderStyle.release());

        m_invalidationBlocked = false;

    }

    maskContext->restore();

    return true;

}

void RenderSVGResourceClipper::calculateClipContentRepaintRect()

{

    // This is a rough heuristic to appraise the clip size and doesn't consider clip on clip.

    for (Node* childNode = node()->firstChild(); childNode; childNode = childNode->nextSibling()) {

        RenderObject* renderer = childNode->renderer();

        if (!childNode->isSVGElement() || !static_cast<SVGElement*>(childNode)->isStyled() || !renderer)

            continue;

        if (!renderer->isRenderPath() && !renderer->isSVGText() && !renderer->isSVGShadowTreeRootContainer())

            continue;

        RenderStyle* style = renderer->style();

        if (!style || style->display() == NONE || style->visibility() != VISIBLE)

             continue;

        m_clipBoundaries.unite(renderer->localToParentTransform().mapRect(renderer->repaintRectInLocalCoordinates()));

    }

}

bool RenderSVGResourceClipper::hitTestClipContent(const FloatRect& objectBoundingBox, const FloatPoint& nodeAtPoint)

{

    // FIXME: We should be able to check whether m_clipper.contains(object) - this doesn't work at the moment

    // as resourceBoundingBox() has already created ClipperData, even if applyResource() returned false.

    // Early exit, if this resource contains a child which references ourselves.

    if (containsCyclicReference(node()))

        return false;

    FloatPoint point = nodeAtPoint;

    if (!SVGRenderSupport::pointInClippingArea(this, point))

        return false;

    if (static_cast<SVGClipPathElement*>(node())->clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {

        AffineTransform transform;

        transform.translate(objectBoundingBox.x(), objectBoundingBox.y());

        transform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());

        point = transform.inverse().mapPoint(point);

    }

    for (Node* childNode = node()->firstChild(); childNode; childNode = childNode->nextSibling()) {

        RenderObject* renderer = childNode->renderer();

        if (!childNode->isSVGElement() || !static_cast<SVGElement*>(childNode)->isStyled() || !renderer)

            continue;

        if (!renderer->isRenderPath() && !renderer->isSVGText() && !renderer->isSVGShadowTreeRootContainer())

            continue;

        IntPoint hitPoint;

        HitTestResult result(hitPoint);

        if (renderer->nodeAtFloatPoint(HitTestRequest(HitTestRequest::SVGClipContent), result, point, HitTestForeground))

            return true;

    }

    return false;

}

bool RenderSVGResourceClipper::childElementReferencesResource(const SVGRenderStyle* style, const String& referenceId) const

{

    if (!style->hasClipper())

        return false;

    return style->clipperResource() == referenceId;

}

FloatRect RenderSVGResourceClipper::resourceBoundingBox(RenderObject* object)

{

    // Resource was not layouted yet. Give back the boundingBox of the object.

    if (selfNeedsLayout())

        return object->objectBoundingBox();

    if (m_clipBoundaries.isEmpty())

        calculateClipContentRepaintRect();

    if (static_cast<SVGClipPathElement*>(node())->clipPathUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {

        FloatRect objectBoundingBox = object->objectBoundingBox();

        AffineTransform transform;

        transform.translate(objectBoundingBox.x(), objectBoundingBox.y());

        transform.scaleNonUniform(objectBoundingBox.width(), objectBoundingBox.height());

        return transform.mapRect(m_clipBoundaries);

    }

    return m_clipBoundaries;

}

}

#endif // ENABLE(SVG)