ScrollAnchor::ExamineResult ScrollAnchor::examine(
const LayoutObject* candidate) const {
if (candidate->isLayoutInline())
return ExamineResult(Continue);
// Anonymous blocks are not in the DOM tree and it may be hard for
// developers to reason about the anchor node.
if (candidate->isAnonymous())
return ExamineResult(Continue);
if (!candidate->isText() && !candidate->isBox())
return ExamineResult(Skip);
if (!candidateMayMoveWithScroller(candidate, m_scroller))
return ExamineResult(Skip);
if (candidate->style()->overflowAnchor() == AnchorNone)
return ExamineResult(Skip);
LayoutRect candidateRect = relativeBounds(candidate, m_scroller);
LayoutRect visibleRect =
scrollerLayoutBoxItem(m_scroller).overflowClipRect(LayoutPoint());
bool occupiesSpace = candidateRect.width() > 0 && candidateRect.height() > 0;
if (occupiesSpace && visibleRect.intersects(candidateRect)) {
return ExamineResult(
visibleRect.contains(candidateRect) ? Return : Constrain,
cornerToAnchor(m_scroller));
} else {
return ExamineResult(Skip);
}
}
bool LayoutImage::updateImageLoadingPriorities()
{
if (!m_imageResource || !m_imageResource->cachedImage() || m_imageResource->cachedImage()->isLoaded())
return false;
LayoutRect viewBounds = viewRect();
LayoutRect objectBounds = LayoutRect(absoluteContentBox());
// The object bounds might be empty right now, so intersects will fail since it doesn't deal
// with empty rects. Use LayoutRect::contains in that case.
bool isVisible;
if (!objectBounds.isEmpty())
isVisible = viewBounds.intersects(objectBounds);
else
isVisible = viewBounds.contains(objectBounds);
ResourceLoadPriorityOptimizer::VisibilityStatus status = isVisible ?
ResourceLoadPriorityOptimizer::Visible : ResourceLoadPriorityOptimizer::NotVisible;
LayoutRect screenArea;
if (!objectBounds.isEmpty()) {
screenArea = viewBounds;
screenArea.intersect(objectBounds);
}
ResourceLoadPriorityOptimizer::resourceLoadPriorityOptimizer()->notifyImageResourceVisibility(m_imageResource->cachedImage(), status, screenArea);
return true;
}
bool RenderFlowThread::objectInFlowRegion(const RenderObject* object, const RenderRegion* region) const
{
ASSERT(object);
ASSERT(region);
if (!object->inRenderFlowThread())
return false;
if (object->enclosingRenderFlowThread() != this)
return false;
if (!m_regionList.contains(const_cast<RenderRegion*>(region)))
return false;
RenderBox* enclosingBox = object->enclosingBox();
RenderRegion* enclosingBoxStartRegion = 0;
RenderRegion* enclosingBoxEndRegion = 0;
getRegionRangeForBox(enclosingBox, enclosingBoxStartRegion, enclosingBoxEndRegion);
if (!regionInRange(region, enclosingBoxStartRegion, enclosingBoxEndRegion))
return false;
if (object->isBox())
return true;
LayoutRect objectABBRect = object->absoluteBoundingBoxRect(true);
if (!objectABBRect.width())
objectABBRect.setWidth(1);
if (!objectABBRect.height())
objectABBRect.setHeight(1);
if (objectABBRect.intersects(region->absoluteBoundingBoxRect(true)))
return true;
if (region == lastRegion()) {
// If the object does not intersect any of the enclosing box regions
// then the object is in last region.
for (RenderRegionList::const_iterator it = m_regionList.find(enclosingBoxStartRegion); it != m_regionList.end(); ++it) {
const RenderRegion* currRegion = *it;
if (!region->isValid())
continue;
if (currRegion == region)
break;
if (objectABBRect.intersects(currRegion->absoluteBoundingBoxRect(true)))
return false;
}
return true;
}
return false;
}
void BlockPainter::paint(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
{
Optional<SubtreeRecorder> subtreeRecorder;
if (needsSubtreeRecorder(m_layoutBlock)) {
subtreeRecorder.emplace(*paintInfo.context, m_layoutBlock, paintInfo.phase);
if (subtreeRecorder->canUseCache())
return;
}
PaintInfo localPaintInfo(paintInfo);
LayoutPoint adjustedPaintOffset = paintOffset + m_layoutBlock.location();
PaintPhase originalPhase = localPaintInfo.phase;
// Check if we need to do anything at all.
LayoutRect overflowBox = overflowRectForPaintRejection();
m_layoutBlock.flipForWritingMode(overflowBox);
overflowBox.moveBy(adjustedPaintOffset);
if (!overflowBox.intersects(LayoutRect(localPaintInfo.rect)))
return;
// There are some cases where not all clipped visual overflow is accounted for.
// FIXME: reduce the number of such cases.
ContentsClipBehavior contentsClipBehavior = ForceContentsClip;
if (m_layoutBlock.hasOverflowClip() && !m_layoutBlock.hasControlClip() && !(m_layoutBlock.shouldPaintSelectionGaps() && originalPhase == PaintPhaseForeground) && !hasCaret())
contentsClipBehavior = SkipContentsClipIfPossible;
if (localPaintInfo.phase == PaintPhaseOutline) {
localPaintInfo.phase = PaintPhaseChildOutlines;
} else if (localPaintInfo.phase == PaintPhaseChildBlockBackground) {
localPaintInfo.phase = PaintPhaseBlockBackground;
m_layoutBlock.paintObject(localPaintInfo, adjustedPaintOffset);
localPaintInfo.phase = PaintPhaseChildBlockBackgrounds;
}
{
BoxClipper boxClipper(m_layoutBlock, localPaintInfo, adjustedPaintOffset, contentsClipBehavior);
m_layoutBlock.paintObject(localPaintInfo, adjustedPaintOffset);
}
if (originalPhase == PaintPhaseOutline) {
localPaintInfo.phase = PaintPhaseSelfOutline;
m_layoutBlock.paintObject(localPaintInfo, adjustedPaintOffset);
localPaintInfo.phase = originalPhase;
} else if (originalPhase == PaintPhaseChildBlockBackground) {
localPaintInfo.phase = originalPhase;
}
// Our scrollbar widgets paint exactly when we tell them to, so that they work properly with
// z-index. We paint after we painted the background/border, so that the scrollbars will
// sit above the background/border.
paintOverflowControlsIfNeeded(localPaintInfo, adjustedPaintOffset);
}
bool BlockPainter::intersectsPaintRect(const PaintInfo& paintInfo, const LayoutPoint& paintOffset) const
{
LayoutRect overflowRect = m_layoutBlock.visualOverflowRect();
if (m_layoutBlock.hasOverflowModel() && m_layoutBlock.usesCompositedScrolling()) {
overflowRect.unite(m_layoutBlock.layoutOverflowRect());
overflowRect.move(-m_layoutBlock.scrolledContentOffset());
}
m_layoutBlock.flipForWritingMode(overflowRect);
overflowRect.moveBy(paintOffset + m_layoutBlock.location());
return (overflowRect.intersects(LayoutRect(paintInfo.rect)));
}
void Page::addRelevantUnpaintedObject(RenderObject* object, const LayoutRect& objectPaintRect)
{
if (!isCountingRelevantRepaintedObjects())
return;
// The objects are only relevant if they are being painted within the relevantViewRect().
if (RenderView* view = object->view()) {
if (!objectPaintRect.intersects(pixelSnappedIntRect(relevantViewRect(view))))
return;
}
m_relevantUnpaintedRenderObjects.add(object);
m_relevantUnpaintedRegion.unite(pixelSnappedIntRect(objectPaintRect));
}
static void deflateIfOverlapped(LayoutRect& a, LayoutRect& b)
{
if (!a.intersects(b) || a.contains(b) || b.contains(a))
return;
LayoutUnit deflateFactor = -fudgeFactor();
// Avoid negative width or height values.
if ((a.width() + 2 * deflateFactor > 0) && (a.height() + 2 * deflateFactor > 0))
a.inflate(deflateFactor);
if ((b.width() + 2 * deflateFactor > 0) && (b.height() + 2 * deflateFactor > 0))
b.inflate(deflateFactor);
}
bool canBeScrolledIntoView(FocusType type, const FocusCandidate& candidate)
{
ASSERT(candidate.visibleNode && candidate.isOffscreen);
LayoutRect candidateRect = candidate.rect;
for (Node* parentNode = candidate.visibleNode->parentNode(); parentNode; parentNode = parentNode->parentNode()) {
LayoutRect parentRect = nodeRectInAbsoluteCoordinates(parentNode);
if (!candidateRect.intersects(parentRect)) {
if (((type == FocusTypeLeft || type == FocusTypeRight) && parentNode->renderer()->style()->overflowX() == OHIDDEN)
|| ((type == FocusTypeUp || type == FocusTypeDown) && parentNode->renderer()->style()->overflowY() == OHIDDEN))
return false;
}
if (parentNode == candidate.enclosingScrollableBox)
return canScrollInDirection(parentNode, type);
}
return true;
}
// Checks if |node| is offscreen the visible area (viewport) of its container
// document. In case it is, one can scroll in direction or take any different
// desired action later on.
bool hasOffscreenRect(Node* node, FocusType type)
{
// Get the FrameView in which |node| is (which means the current viewport if |node|
// is not in an inner document), so we can check if its content rect is visible
// before we actually move the focus to it.
FrameView* frameView = node->document().view();
if (!frameView)
return true;
ASSERT(!frameView->needsLayout());
LayoutRect containerViewportRect = frameView->visibleContentRect();
// We want to select a node if it is currently off screen, but will be
// exposed after we scroll. Adjust the viewport to post-scrolling position.
// If the container has overflow:hidden, we cannot scroll, so we do not pass direction
// and we do not adjust for scrolling.
switch (type) {
case FocusTypeLeft:
containerViewportRect.setX(containerViewportRect.x() - ScrollableArea::pixelsPerLineStep());
containerViewportRect.setWidth(containerViewportRect.width() + ScrollableArea::pixelsPerLineStep());
break;
case FocusTypeRight:
containerViewportRect.setWidth(containerViewportRect.width() + ScrollableArea::pixelsPerLineStep());
break;
case FocusTypeUp:
containerViewportRect.setY(containerViewportRect.y() - ScrollableArea::pixelsPerLineStep());
containerViewportRect.setHeight(containerViewportRect.height() + ScrollableArea::pixelsPerLineStep());
break;
case FocusTypeDown:
containerViewportRect.setHeight(containerViewportRect.height() + ScrollableArea::pixelsPerLineStep());
break;
default:
break;
}
RenderObject* render = node->renderer();
if (!render)
return true;
LayoutRect rect(render->absoluteClippedOverflowRect());
if (rect.isEmpty())
return true;
return !containerViewportRect.intersects(rect);
}
// Hit Testing
bool RenderRegion::nodeAtPoint(const HitTestRequest& request, HitTestResult& result, const LayoutPoint& pointInContainer, const LayoutPoint& accumulatedOffset, HitTestAction action)
{
if (!isValid())
return false;
LayoutPoint adjustedLocation = accumulatedOffset + location();
// Check our bounds next. For this purpose always assume that we can only be hit in the
// foreground phase (which is true for replaced elements like images).
LayoutRect boundsRect = borderBoxRectInRegion(result.region());
boundsRect.moveBy(adjustedLocation);
if (visibleToHitTesting() && action == HitTestForeground && boundsRect.intersects(result.rectForPoint(pointInContainer))) {
// Check the contents of the RenderFlowThread.
if (m_flowThread && m_flowThread->hitTestRegion(this, request, result, pointInContainer, LayoutPoint(adjustedLocation.x() + borderLeft() + paddingLeft(), adjustedLocation.y() + borderTop() + paddingTop())))
return true;
updateHitTestResult(result, pointInContainer - toLayoutSize(adjustedLocation));
if (!result.addNodeToRectBasedTestResult(node(), pointInContainer, boundsRect))
return true;
}
return false;
}
void Page::addRelevantRepaintedObject(RenderObject* object, const LayoutRect& objectPaintRect)
{
if (!isCountingRelevantRepaintedObjects())
return;
// Objects inside sub-frames are not considered to be relevant.
if (object->document()->frame() != mainFrame())
return;
RenderView* view = object->view();
if (!view)
return;
LayoutRect relevantRect = relevantViewRect(view);
// The objects are only relevant if they are being painted within the viewRect().
if (!objectPaintRect.intersects(pixelSnappedIntRect(relevantRect)))
return;
IntRect snappedPaintRect = pixelSnappedIntRect(objectPaintRect);
// If this object was previously counted as an unpainted object, remove it from that HashSet
// and corresponding Region. FIXME: This doesn't do the right thing if the objects overlap.
HashSet<RenderObject*>::iterator it = m_relevantUnpaintedRenderObjects.find(object);
if (it != m_relevantUnpaintedRenderObjects.end()) {
m_relevantUnpaintedRenderObjects.remove(it);
m_relevantUnpaintedRegion.subtract(snappedPaintRect);
}
// Split the relevantRect into a top half and a bottom half. Making sure we have coverage in
// both halves helps to prevent cases where we have a fully loaded menu bar or masthead with
// no content beneath that.
LayoutRect topRelevantRect = relevantRect;
topRelevantRect.contract(LayoutSize(0, relevantRect.height() / 2));
LayoutRect bottomRelevantRect = topRelevantRect;
bottomRelevantRect.setY(relevantRect.height() / 2);
// If the rect straddles both Regions, split it appropriately.
if (topRelevantRect.intersects(snappedPaintRect) && bottomRelevantRect.intersects(snappedPaintRect)) {
IntRect topIntersection = snappedPaintRect;
topIntersection.intersect(pixelSnappedIntRect(topRelevantRect));
m_topRelevantPaintedRegion.unite(topIntersection);
IntRect bottomIntersection = snappedPaintRect;
bottomIntersection.intersect(pixelSnappedIntRect(bottomRelevantRect));
m_bottomRelevantPaintedRegion.unite(bottomIntersection);
} else if (topRelevantRect.intersects(snappedPaintRect))
m_topRelevantPaintedRegion.unite(snappedPaintRect);
else
m_bottomRelevantPaintedRegion.unite(snappedPaintRect);
float topPaintedArea = m_topRelevantPaintedRegion.totalArea();
float bottomPaintedArea = m_bottomRelevantPaintedRegion.totalArea();
float viewArea = relevantRect.width() * relevantRect.height();
float ratioThatIsPaintedOnTop = topPaintedArea / viewArea;
float ratioThatIsPaintedOnBottom = bottomPaintedArea / viewArea;
float ratioOfViewThatIsUnpainted = m_relevantUnpaintedRegion.totalArea() / viewArea;
if (ratioThatIsPaintedOnTop > (gMinimumPaintedAreaRatio / 2) && ratioThatIsPaintedOnBottom > (gMinimumPaintedAreaRatio / 2)
&& ratioOfViewThatIsUnpainted < gMaximumUnpaintedAreaRatio) {
m_isCountingRelevantRepaintedObjects = false;
resetRelevantPaintedObjectCounter();
if (Frame* frame = mainFrame())
frame->loader()->didLayout(DidHitRelevantRepaintedObjectsAreaThreshold);
}
}
bool CompositingReasonFinder::requiresCompositingForPosition(RenderObject* renderer, const RenderLayer* layer, RenderLayer::ViewportConstrainedNotCompositedReason* viewportConstrainedNotCompositedReason, bool* needToRecomputeCompositingRequirements) const
{
// position:fixed elements that create their own stacking context (e.g. have an explicit z-index,
// opacity, transform) can get their own composited layer. A stacking context is required otherwise
// z-index and clipping will be broken.
if (!renderer->isPositioned())
return false;
EPosition position = renderer->style()->position();
bool isFixed = renderer->isOutOfFlowPositioned() && position == FixedPosition;
// FIXME: The isStackingContainer check here is redundant. Fixed position elements are always stacking contexts.
if (isFixed && !layer->stackingNode()->isStackingContainer())
return false;
bool isSticky = renderer->isInFlowPositioned() && position == StickyPosition;
if (!isFixed && !isSticky)
return false;
// FIXME: acceleratedCompositingForFixedPositionEnabled should probably be renamed acceleratedCompositingForViewportConstrainedPositionEnabled().
if (Settings* settings = m_renderView.document().settings()) {
if (!settings->acceleratedCompositingForFixedPositionEnabled())
return false;
}
if (isSticky)
return isViewportConstrainedFixedOrStickyLayer(layer);
RenderObject* container = renderer->container();
// If the renderer is not hooked up yet then we have to wait until it is.
if (!container) {
*needToRecomputeCompositingRequirements = true;
return false;
}
// Don't promote fixed position elements that are descendants of a non-view container, e.g. transformed elements.
// They will stay fixed wrt the container rather than the enclosing frame.
if (container != &m_renderView) {
if (viewportConstrainedNotCompositedReason)
*viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForNonViewContainer;
return false;
}
// If the fixed-position element does not have any scrollable ancestor between it and
// its container, then we do not need to spend compositor resources for it. Start by
// assuming we can opt-out (i.e. no scrollable ancestor), and refine the answer below.
bool hasScrollableAncestor = false;
// The FrameView has the scrollbars associated with the top level viewport, so we have to
// check the FrameView in addition to the hierarchy of ancestors.
FrameView* frameView = m_renderView.frameView();
if (frameView && frameView->isScrollable())
hasScrollableAncestor = true;
RenderLayer* ancestor = layer->parent();
while (ancestor && !hasScrollableAncestor) {
if (frameView->containsScrollableArea(ancestor->scrollableArea()))
hasScrollableAncestor = true;
if (ancestor->renderer() == &m_renderView)
break;
ancestor = ancestor->parent();
}
if (!hasScrollableAncestor) {
if (viewportConstrainedNotCompositedReason)
*viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForUnscrollableAncestors;
return false;
}
// Subsequent tests depend on layout. If we can't tell now, just keep things the way they are until layout is done.
if (m_renderView.document().lifecycle().state() < DocumentLifecycle::LayoutClean) {
*needToRecomputeCompositingRequirements = true;
return layer->hasCompositedLayerMapping();
}
bool paintsContent = layer->isVisuallyNonEmpty() || layer->hasVisibleDescendant();
if (!paintsContent) {
if (viewportConstrainedNotCompositedReason)
*viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForNoVisibleContent;
return false;
}
// Fixed position elements that are invisible in the current view don't get their own layer.
if (FrameView* frameView = m_renderView.frameView()) {
LayoutRect viewBounds = frameView->viewportConstrainedVisibleContentRect();
LayoutRect layerBounds = layer->calculateLayerBounds(layer->compositor()->rootRenderLayer(), 0,
RenderLayer::DefaultCalculateLayerBoundsFlags
| RenderLayer::ExcludeHiddenDescendants
| RenderLayer::DontConstrainForMask
| RenderLayer::IncludeCompositedDescendants
| RenderLayer::PretendLayerHasOwnBacking);
if (!viewBounds.intersects(enclosingIntRect(layerBounds))) {
if (viewportConstrainedNotCompositedReason) {
*viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForBoundsOutOfView;
*needToRecomputeCompositingRequirements = true;
}
return false;
}
}
return true;
}
bool CompositingReasonFinder::requiresCompositingForPositionFixed(RenderObject* renderer, const RenderLayer* layer, RenderLayer::ViewportConstrainedNotCompositedReason* viewportConstrainedNotCompositedReason, bool* needToRecomputeCompositingRequirements) const
{
if (!(m_compositingTriggers & ViewportConstrainedPositionedTrigger))
return false;
if (renderer->style()->position() != FixedPosition)
return false;
RenderObject* container = renderer->container();
// If the renderer is not hooked up yet then we have to wait until it is.
if (!container) {
ASSERT(m_renderView.document().lifecycle().state() < DocumentLifecycle::InCompositingUpdate);
// FIXME: Remove this and ASSERT(container) once we get rid of the incremental
// allocateOrClearCompositedLayerMapping compositing update. This happens when
// adding the renderer to the tree because we setStyle before addChild in
// createRendererForElementIfNeeded.
*needToRecomputeCompositingRequirements = true;
return false;
}
// Don't promote fixed position elements that are descendants of a non-view container, e.g. transformed elements.
// They will stay fixed wrt the container rather than the enclosing frame.
if (container != &m_renderView) {
if (viewportConstrainedNotCompositedReason)
*viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForNonViewContainer;
return false;
}
// If the fixed-position element does not have any scrollable ancestor between it and
// its container, then we do not need to spend compositor resources for it. Start by
// assuming we can opt-out (i.e. no scrollable ancestor), and refine the answer below.
bool hasScrollableAncestor = false;
// The FrameView has the scrollbars associated with the top level viewport, so we have to
// check the FrameView in addition to the hierarchy of ancestors.
FrameView* frameView = m_renderView.frameView();
if (frameView && frameView->isScrollable())
hasScrollableAncestor = true;
RenderLayer* ancestor = layer->parent();
while (ancestor && !hasScrollableAncestor) {
if (ancestor->scrollsOverflow())
hasScrollableAncestor = true;
if (ancestor->renderer() == &m_renderView)
break;
ancestor = ancestor->parent();
}
if (!hasScrollableAncestor) {
if (viewportConstrainedNotCompositedReason)
*viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForUnscrollableAncestors;
return false;
}
// Subsequent tests depend on layout. If we can't tell now, just keep things the way they are until layout is done.
// FIXME: Get rid of this codepath once we get rid of the incremental compositing update in RenderLayer::styleChanged.
if (m_renderView.document().lifecycle().state() < DocumentLifecycle::LayoutClean) {
*needToRecomputeCompositingRequirements = true;
return layer->hasCompositedLayerMapping();
}
bool paintsContent = layer->isVisuallyNonEmpty() || layer->hasVisibleDescendant();
if (!paintsContent) {
if (viewportConstrainedNotCompositedReason)
*viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForNoVisibleContent;
return false;
}
// Fixed position elements that are invisible in the current view don't get their own layer.
if (FrameView* frameView = m_renderView.frameView()) {
ASSERT(m_renderView.document().lifecycle().state() == DocumentLifecycle::InCompositingUpdate);
LayoutRect viewBounds = frameView->viewportConstrainedVisibleContentRect();
LayoutRect layerBounds = layer->boundingBoxForCompositing(layer->compositor()->rootRenderLayer(), RenderLayer::ApplyBoundsChickenEggHacks);
if (!viewBounds.intersects(enclosingIntRect(layerBounds))) {
if (viewportConstrainedNotCompositedReason)
*viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForBoundsOutOfView;
return false;
}
}
return true;
}