ScrollingTreeStickyNode.mm [plain text]
/*
* Copyright (C) 2012 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. AND ITS CONTRIBUTORS ``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 INC. OR ITS 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 "ScrollingTreeStickyNode.h"
#if ENABLE(THREADED_SCROLLING)
#include "ScrollingStateStickyNode.h"
#include "ScrollingTree.h"
namespace WebCore {
PassOwnPtr<ScrollingTreeStickyNode> ScrollingTreeStickyNode::create(ScrollingTree* scrollingTree, ScrollingNodeID nodeID)
{
return adoptPtr(new ScrollingTreeStickyNode(scrollingTree, nodeID));
}
ScrollingTreeStickyNode::ScrollingTreeStickyNode(ScrollingTree* scrollingTree, ScrollingNodeID nodeID)
: ScrollingTreeNode(scrollingTree, nodeID)
{
}
ScrollingTreeStickyNode::~ScrollingTreeStickyNode()
{
}
void ScrollingTreeStickyNode::updateBeforeChildren(ScrollingStateNode* stateNode)
{
ScrollingStateStickyNode* stickyStateNode = toScrollingStateStickyNode(stateNode);
if (stickyStateNode->hasChangedProperty(ScrollingStateNode::ScrollLayer))
m_layer = stickyStateNode->platformScrollLayer();
if (stateNode->hasChangedProperty(ScrollingStateStickyNode::ViewportConstraints))
m_constraints = stickyStateNode->viewportConstraints();
}
static inline CGPoint operator*(CGPoint& a, const CGSize& b)
{
return CGPointMake(a.x * b.width, a.y * b.height);
}
void ScrollingTreeStickyNode::parentScrollPositionDidChange(const IntRect& viewportRect, const FloatSize& cumulativeDelta)
{
FloatPoint layerPosition = m_constraints.layerPositionForConstrainingRect(viewportRect);
// FIXME: Subtracting the cumulativeDelta is not totally sufficient to get the new position right for nested
// sticky objects. We probably need a way to modify the containingBlockRect in the ViewportContraints
// to get this right in all cases.
layerPosition -= cumulativeDelta;
CGRect layerBounds = [m_layer.get() bounds];
CGPoint anchorPoint = [m_layer.get() anchorPoint];
CGPoint newPosition = layerPosition - m_constraints.alignmentOffset() + anchorPoint * layerBounds.size;
[m_layer.get() setPosition:newPosition];
if (!m_children)
return;
FloatSize newDelta = layerPosition - m_constraints.layerPositionAtLastLayout() + cumulativeDelta;
size_t size = m_children->size();
for (size_t i = 0; i < size; ++i)
m_children->at(i)->parentScrollPositionDidChange(viewportRect, newDelta);
}
} // namespace WebCore
#endif // ENABLE(THREADED_SCROLLING)