static void adjustClipRectsForChildren(const LayoutObject& layoutObject, ClipRects& clipRects)
{
EPosition position = layoutObject.style()->position();
// A fixed object is essentially the root of its containing block hierarchy, so when
// we encounter such an object, we reset our clip rects to the fixedClipRect.
if (position == FixedPosition) {
clipRects.setPosClipRect(clipRects.fixedClipRect());
clipRects.setOverflowClipRect(clipRects.fixedClipRect());
clipRects.setFixed(true);
} else if (position == RelativePosition) {
clipRects.setPosClipRect(clipRects.overflowClipRect());
} else if (position == AbsolutePosition) {
clipRects.setOverflowClipRect(clipRects.posClipRect());
}
}
void RenderLayerClipper::calculateClipRects(const ClipRectsContext& clipRectsContext, ClipRects& clipRects) const
{
if (!m_renderer->layer()->parent()) {
// The root layer's clip rect is always infinite.
clipRects.reset(PaintInfo::infiniteRect());
return;
}
ClipRectsType clipRectsType = clipRectsContext.clipRectsType;
bool useCached = clipRectsType != TemporaryClipRects;
// For transformed layers, the root layer was shifted to be us, so there is no need to
// examine the parent. We want to cache clip rects with us as the root.
RenderLayer* parentLayer = clipRectsContext.rootLayer != m_renderer->layer() ? m_renderer->layer()->parent() : 0;
// Ensure that our parent's clip has been calculated so that we can examine the values.
if (parentLayer) {
if (useCached && parentLayer->clipper().clipRects(clipRectsContext)) {
clipRects = *parentLayer->clipper().clipRects(clipRectsContext);
} else {
ClipRectsContext parentContext(clipRectsContext);
parentContext.overlayScrollbarSizeRelevancy = IgnoreOverlayScrollbarSize; // FIXME: why?
parentLayer->clipper().calculateClipRects(parentContext, clipRects);
}
} else {
clipRects.reset(PaintInfo::infiniteRect());
}
// A fixed object is essentially the root of its containing block hierarchy, so when
// we encounter such an object, we reset our clip rects to the fixedClipRect.
if (m_renderer->style()->position() == FixedPosition) {
clipRects.setPosClipRect(clipRects.fixedClipRect());
clipRects.setOverflowClipRect(clipRects.fixedClipRect());
clipRects.setFixed(true);
} else if (m_renderer->style()->hasInFlowPosition()) {
clipRects.setPosClipRect(clipRects.overflowClipRect());
} else if (m_renderer->style()->position() == AbsolutePosition) {
clipRects.setOverflowClipRect(clipRects.posClipRect());
}
// Update the clip rects that will be passed to child layers.
if ((m_renderer->hasOverflowClip() && (clipRectsContext.respectOverflowClip == RespectOverflowClip || m_renderer->layer() != clipRectsContext.rootLayer)) || m_renderer->hasClip()) {
// This layer establishes a clip of some kind.
// This offset cannot use convertToLayerCoords, because sometimes our rootLayer may be across
// some transformed layer boundary, for example, in the RenderLayerCompositor overlapMap, where
// clipRects are needed in view space.
LayoutPoint offset;
offset = roundedLayoutPoint(m_renderer->localToContainerPoint(FloatPoint(), clipRectsContext.rootLayer->renderer()));
RenderView* view = m_renderer->view();
ASSERT(view);
if (view && clipRects.fixed() && clipRectsContext.rootLayer->renderer() == view) {
offset -= view->frameView()->scrollOffsetForFixedPosition();
}
if (m_renderer->hasOverflowClip()) {
ClipRect newOverflowClip = toRenderBox(m_renderer)->overflowClipRect(offset, clipRectsContext.region, clipRectsContext.overlayScrollbarSizeRelevancy);
if (m_renderer->style()->hasBorderRadius())
newOverflowClip.setHasRadius(true);
clipRects.setOverflowClipRect(intersection(newOverflowClip, clipRects.overflowClipRect()));
if (m_renderer->isPositioned())
clipRects.setPosClipRect(intersection(newOverflowClip, clipRects.posClipRect()));
}
if (m_renderer->hasClip()) {
LayoutRect newPosClip = toRenderBox(m_renderer)->clipRect(offset, clipRectsContext.region);
clipRects.setPosClipRect(intersection(newPosClip, clipRects.posClipRect()));
clipRects.setOverflowClipRect(intersection(newPosClip, clipRects.overflowClipRect()));
clipRects.setFixedClipRect(intersection(newPosClip, clipRects.fixedClipRect()));
}
}
}