Source/core/rendering/RenderLayerBlendInfo.cpp

/*
 * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
 *
 * Portions are Copyright (C) 1998 Netscape Communications Corporation.
 *
 * Other contributors:
 *   Robert O'Callahan <roc+@cs.cmu.edu>
 *   David Baron <dbaron@fas.harvard.edu>
 *   Christian Biesinger <cbiesinger@web.de>
 *   Randall Jesup <rjesup@wgate.com>
 *   Roland Mainz <roland.mainz@informatik.med.uni-giessen.de>
 *   Josh Soref <timeless@mac.com>
 *   Boris Zbarsky <bzbarsky@mit.edu>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Alternatively, the contents of this file may be used under the terms
 * of either the Mozilla Public License Version 1.1, found at
 * http://www.mozilla.org/MPL/ (the "MPL") or the GNU General Public
 * License Version 2.0, found at http://www.fsf.org/copyleft/gpl.html
 * (the "GPL"), in which case the provisions of the MPL or the GPL are
 * applicable instead of those above.  If you wish to allow use of your
 * version of this file only under the terms of one of those two
 * licenses (the MPL or the GPL) and not to allow others to use your
 * version of this file under the LGPL, indicate your decision by
 * deletingthe provisions above and replace them with the notice and
 * other provisions required by the MPL or the GPL, as the case may be.
 * If you do not delete the provisions above, a recipient may use your
 * version of this file under any of the LGPL, the MPL or the GPL.
 */

#include "config.h"
#include "core/rendering/RenderLayerBlendInfo.h"

#include "core/rendering/CompositedLayerMapping.h"
#include "core/rendering/RenderLayer.h"
#include "core/rendering/RenderLayerModelObject.h"

namespace WebCore {

RenderLayerBlendInfo::RenderLayerBlendInfo(RenderLayerModelObject* renderer)
    : m_renderer(renderer)
    , m_blendMode(blink::WebBlendModeNormal)
    , m_childLayerHasBlendMode(false)
    , m_childLayerHasBlendModeStatusDirty(false)
{
}

bool RenderLayerBlendInfo::hasBlendMode() const
{
    return RuntimeEnabledFeatures::cssCompositingEnabled() && m_renderer->hasBlendMode();
}

void RenderLayerBlendInfo::updateBlendMode()
{
    if (!RuntimeEnabledFeatures::cssCompositingEnabled())
        return;

    blink::WebBlendMode newBlendMode = m_renderer->style()->blendMode();
    if (newBlendMode == m_blendMode)
        return;

    bool hadBlendMode = m_blendMode != blink::WebBlendModeNormal;
    m_blendMode = newBlendMode;

    RenderLayer* layer = m_renderer->layer();
    // Only update the flag if a blend mode is set or unset.
    if (layer->parent() && (!hadBlendMode || !hasBlendMode()))
        layer->parent()->blendInfo().dirtyAncestorChainBlendedDescendantStatus();

    if (layer->hasCompositedLayerMapping())
        layer->compositedLayerMapping()->setBlendMode(newBlendMode);
}

void RenderLayerBlendInfo::dirtyAncestorChainBlendedDescendantStatus()
{
    for (RenderLayer* layer = m_renderer->layer(); layer; layer = layer->parent()) {
        if (layer->blendInfo().childLayerHasBlendModeStatusDirty())
            break;

        layer->blendInfo().setChildLayerHasBlendModeStatusDirty(true);

        if (layer->stackingNode()->isStackingContext())
            break;
    }
}

void RenderLayerBlendInfo::setAncestorChainBlendedDescendant()
{
    for (RenderLayer* layer = m_renderer->layer(); layer; layer = layer->parent()) {
        if (!layer->blendInfo().childLayerHasBlendModeStatusDirty() && layer->blendInfo().childLayerHasBlendMode())
            break;

        layer->blendInfo().setChildLayerHasBlendMode(true);
        layer->blendInfo().setChildLayerHasBlendModeStatusDirty(false);

        if (layer->stackingNode()->isStackingContext())
            break;
    }
}

} // namespace WebCore