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

/*
 * Copyright (C) 2013 Adobe Systems Inc. All rights reserved.
 * Copyright (C) 2013 Google Inc.  All rights reserved.
 * Copyright (C) 2011 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"
#include "core/layout/svg/ReferenceFilterBuilder.h"

#include "core/dom/Element.h"
#include "core/fetch/DocumentResource.h"
#include "core/layout/LayoutBox.h"
#include "core/svg/SVGDocumentExtensions.h"
#include "core/svg/SVGFilterElement.h"
#include "core/svg/graphics/filters/SVGFilterBuilder.h"
#include "platform/graphics/filters/Filter.h"
#include "platform/graphics/filters/SourceGraphic.h"

namespace blink {

HashMap<const FilterOperation*, OwnPtr<DocumentResourceReference>>* ReferenceFilterBuilder::documentResourceReferences = nullptr;

DocumentResourceReference* ReferenceFilterBuilder::documentResourceReference(const FilterOperation* filterOperation)
{
    if (!documentResourceReferences)
        return nullptr;

    return documentResourceReferences->get(filterOperation);
}

void ReferenceFilterBuilder::setDocumentResourceReference(const FilterOperation* filterOperation, PassOwnPtr<DocumentResourceReference> documentResourceReference)
{
    if (!documentResourceReferences)
        documentResourceReferences = new HashMap<const FilterOperation*, OwnPtr<DocumentResourceReference>>;
    documentResourceReferences->add(filterOperation, documentResourceReference);
}

void ReferenceFilterBuilder::clearDocumentResourceReference(const FilterOperation* filterOperation)
{
    if (!documentResourceReferences)
        return;

    documentResourceReferences->remove(filterOperation);
}

PassRefPtrWillBeRawPtr<Filter> ReferenceFilterBuilder::build(float zoom, Element* element, FilterEffect* previousEffect, const ReferenceFilterOperation& filterOperation)
{
    TreeScope* treeScope = &element->treeScope();

    if (DocumentResourceReference* documentResourceRef = documentResourceReference(&filterOperation)) {
        DocumentResource* cachedSVGDocument = documentResourceRef->document();

        // If we have an SVG document, this is an external reference. Otherwise
        // we look up the referenced node in the current document.
        if (cachedSVGDocument)
            treeScope = cachedSVGDocument->document();
    }

    if (!treeScope)
        return nullptr;

    Element* filter = treeScope->getElementById(filterOperation.fragment());

    if (!filter) {
        // Although we did not find the referenced filter, it might exist later
        // in the document.
        treeScope->document().accessSVGExtensions().addPendingResource(filterOperation.fragment(), element);
        return nullptr;
    }

    if (!isSVGFilterElement(*filter))
        return nullptr;

    SVGFilterElement& filterElement = toSVGFilterElement(*filter);

    FloatRect referenceBox;
    if (element->inDocument() && element->layoutObject() && element->layoutObject()->isBoxModelObject())
        referenceBox = toLayoutBoxModelObject(element->layoutObject())->borderBoundingBox();
    referenceBox.scale(1.0f / zoom);
    FloatRect filterRegion = SVGLengthContext::resolveRectangle<SVGFilterElement>(&filterElement, filterElement.filterUnits()->currentValue()->enumValue(), referenceBox);
    bool primitiveBoundingBoxMode = filterElement.primitiveUnits()->currentValue()->enumValue() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX;
    Filter::UnitScaling unitScaling = primitiveBoundingBoxMode ? Filter::BoundingBox : Filter::UserSpace;
    RefPtrWillBeRawPtr<Filter> result(Filter::create(referenceBox, filterRegion, zoom, unitScaling));
    if (!previousEffect)
        previousEffect = result->sourceGraphic();

    SVGFilterBuilder builder(previousEffect);
    builder.buildGraph(result.get(), filterElement, referenceBox);

    result->setLastEffect(builder.lastEffect());
    return result.release();
}

} // namespace blink