// Modifies the top of the graphics layer tree to add layers needed to support
// the inner/outer viewport fixed-position model for pinch zoom. When finished,
// the tree will look like this (with * denoting added layers):
//
// *rootTransformLayer
// +- *innerViewportContainerLayer (fixed pos container)
// | +- *overscrollElasticityLayer
// | +- *pageScaleLayer
// | +- *innerViewportScrollLayer
// | +-- overflowControlsHostLayer (root layer)
// | +-- outerViewportContainerLayer (fixed pos container) [frame container layer in PaintLayerCompositor]
// | | +-- outerViewportScrollLayer [frame scroll layer in PaintLayerCompositor]
// | | +-- content layers ...
// +- horizontalScrollbarLayer
// +- verticalScrollbarLayer
// +- scroll corner (non-overlay only)
//
void VisualViewport::attachToLayerTree(GraphicsLayer* currentLayerTreeRoot, GraphicsLayerFactory* graphicsLayerFactory)
{
TRACE_EVENT1("blink", "VisualViewport::attachToLayerTree", "currentLayerTreeRoot", (bool)currentLayerTreeRoot);
if (!currentLayerTreeRoot) {
if (m_innerViewportScrollLayer)
m_innerViewportScrollLayer->removeAllChildren();
return;
}
if (currentLayerTreeRoot->parent() && currentLayerTreeRoot->parent() == m_innerViewportScrollLayer)
return;
if (!m_innerViewportScrollLayer) {
ASSERT(!m_overlayScrollbarHorizontal
&& !m_overlayScrollbarVertical
&& !m_overscrollElasticityLayer
&& !m_pageScaleLayer
&& !m_innerViewportContainerLayer);
// FIXME: The root transform layer should only be created on demand.
m_rootTransformLayer = GraphicsLayer::create(graphicsLayerFactory, this);
m_innerViewportContainerLayer = GraphicsLayer::create(graphicsLayerFactory, this);
m_overscrollElasticityLayer = GraphicsLayer::create(graphicsLayerFactory, this);
m_pageScaleLayer = GraphicsLayer::create(graphicsLayerFactory, this);
m_innerViewportScrollLayer = GraphicsLayer::create(graphicsLayerFactory, this);
m_overlayScrollbarHorizontal = GraphicsLayer::create(graphicsLayerFactory, this);
m_overlayScrollbarVertical = GraphicsLayer::create(graphicsLayerFactory, this);
ScrollingCoordinator* coordinator = frameHost().page().scrollingCoordinator();
ASSERT(coordinator);
coordinator->setLayerIsContainerForFixedPositionLayers(m_innerViewportScrollLayer.get(), true);
// Set masks to bounds so the compositor doesn't clobber a manually
// set inner viewport container layer size.
m_innerViewportContainerLayer->setMasksToBounds(frameHost().settings().mainFrameClipsContent());
m_innerViewportContainerLayer->setSize(m_size);
m_innerViewportScrollLayer->platformLayer()->setScrollClipLayer(
m_innerViewportContainerLayer->platformLayer());
m_innerViewportScrollLayer->platformLayer()->setUserScrollable(true, true);
m_rootTransformLayer->addChild(m_innerViewportContainerLayer.get());
m_innerViewportContainerLayer->addChild(m_overscrollElasticityLayer.get());
m_overscrollElasticityLayer->addChild(m_pageScaleLayer.get());
m_pageScaleLayer->addChild(m_innerViewportScrollLayer.get());
// Ensure this class is set as the scroll layer's ScrollableArea.
coordinator->scrollableAreaScrollLayerDidChange(this);
initializeScrollbars();
}
m_innerViewportScrollLayer->removeAllChildren();
m_innerViewportScrollLayer->addChild(currentLayerTreeRoot);
}
void PinchViewport::setLocation(const FloatPoint& newLocation)
{
FloatPoint clampedOffset(clampOffsetToBoundaries(newLocation));
if (clampedOffset == m_offset)
return;
m_offset = clampedOffset;
ScrollingCoordinator* coordinator = m_frameHost.page().scrollingCoordinator();
ASSERT(coordinator);
coordinator->scrollableAreaScrollLayerDidChange(this);
mainFrame()->loader().saveScrollState();
}