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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "config.h"
#include "core/rendering/compositing/CompositingReasonFinder.h"
#include "core/frame/FrameView.h"
#include "core/frame/Settings.h"
#include "core/page/Page.h"
#include "core/rendering/RenderView.h"
#include "core/rendering/compositing/RenderLayerCompositor.h"
namespace WebCore {
CompositingReasonFinder::CompositingReasonFinder(RenderView& renderView)
: m_renderView(renderView)
, m_compositingTriggers(static_cast<CompositingTriggerFlags>(AllCompositingTriggers))
{
updateTriggers();
}
void CompositingReasonFinder::updateTriggers()
{
m_compositingTriggers = 0;
Settings& settings = m_renderView.document().page()->settings();
if (settings.acceleratedCompositingForVideoEnabled())
m_compositingTriggers |= VideoTrigger;
if (settings.acceleratedCompositingForCanvasEnabled())
m_compositingTriggers |= CanvasTrigger;
if (settings.compositedScrollingForFramesEnabled())
m_compositingTriggers |= ScrollableInnerFrameTrigger;
if (settings.acceleratedCompositingForFiltersEnabled())
m_compositingTriggers |= FilterTrigger;
// We map both these settings to universal overlow scrolling.
// FIXME: Replace these settings with a generic compositing setting for HighDPI.
if (settings.acceleratedCompositingForOverflowScrollEnabled() || settings.compositorDrivenAcceleratedScrollingEnabled())
m_compositingTriggers |= OverflowScrollTrigger;
// FIXME: acceleratedCompositingForFixedPositionEnabled should be renamed acceleratedCompositingForViewportConstrainedPositionEnabled().
// Or the sticky and fixed position elements should be behind different flags.
if (settings.acceleratedCompositingForFixedPositionEnabled())
m_compositingTriggers |= ViewportConstrainedPositionedTrigger;
}
bool CompositingReasonFinder::hasOverflowScrollTrigger() const
{
return m_compositingTriggers & OverflowScrollTrigger;
}
bool CompositingReasonFinder::isMainFrame() const
{
// FIXME: LocalFrame::isMainFrame() is probably better.
return !m_renderView.document().ownerElement();
}
CompositingReasons CompositingReasonFinder::directReasons(const RenderLayer* layer) const
{
CompositingReasons styleReasons = layer->styleDeterminedCompositingReasons();
ASSERT(styleDeterminedReasons(layer->renderer()) == styleReasons);
return styleReasons | nonStyleDeterminedDirectReasons(layer);
}
// This information doesn't appear to be incorporated into CompositingReasons.
bool CompositingReasonFinder::requiresCompositingForScrollableFrame() const
{
// Need this done first to determine overflow.
ASSERT(!m_renderView.needsLayout());
if (isMainFrame())
return false;
if (!(m_compositingTriggers & ScrollableInnerFrameTrigger))
return false;
return m_renderView.frameView()->isScrollable();
}
CompositingReasons CompositingReasonFinder::styleDeterminedReasons(RenderObject* renderer) const
{
CompositingReasons directReasons = CompositingReasonNone;
RenderStyle* style = renderer->style();
if (requiresCompositingForTransform(renderer))
directReasons |= CompositingReason3DTransform;
if (requiresCompositingForFilters(renderer))
directReasons |= CompositingReasonFilters;
if (style->backfaceVisibility() == BackfaceVisibilityHidden)
directReasons |= CompositingReasonBackfaceVisibilityHidden;
if (requiresCompositingForAnimation(style))
directReasons |= CompositingReasonActiveAnimation;
if (style->hasWillChangeCompositingHint() && !style->subtreeWillChangeContents())
directReasons |= CompositingReasonWillChangeCompositingHint;
ASSERT(!(directReasons & ~CompositingReasonComboAllStyleDeterminedReasons));
return directReasons;
}
bool CompositingReasonFinder::requiresCompositingForTransform(RenderObject* renderer) const
{
// Note that we ask the renderer if it has a transform, because the style may have transforms,
// but the renderer may be an inline that doesn't suppport them.
return renderer->hasTransform() && renderer->style()->transform().has3DOperation();
}
bool CompositingReasonFinder::requiresCompositingForFilters(RenderObject* renderer) const
{
if (!(m_compositingTriggers & FilterTrigger))
return false;
return renderer->hasFilter();
}
CompositingReasons CompositingReasonFinder::nonStyleDeterminedDirectReasons(const RenderLayer* layer) const
{
CompositingReasons directReasons = CompositingReasonNone;
RenderObject* renderer = layer->renderer();
if (hasOverflowScrollTrigger()) {
// IsUnclippedDescendant is only actually stale during the chicken/egg code path.
// FIXME: Use compositingInputs().isUnclippedDescendant to ASSERT that
// this value isn't stale.
if (layer->compositingInputs().isUnclippedDescendant)
directReasons |= CompositingReasonOutOfFlowClipping;
if (layer->scrollParent())
directReasons |= CompositingReasonOverflowScrollingParent;
if (layer->needsCompositedScrolling())
directReasons |= CompositingReasonOverflowScrollingTouch;
}
if (requiresCompositingForPositionFixed(renderer, layer, 0))
directReasons |= CompositingReasonPositionFixed;
directReasons |= renderer->additionalCompositingReasons(m_compositingTriggers);
ASSERT(!(directReasons & CompositingReasonComboAllStyleDeterminedReasons));
return directReasons;
}
bool CompositingReasonFinder::requiresCompositingForAnimation(RenderStyle* style) const
{
if (style->subtreeWillChangeContents())
return style->isRunningAnimationOnCompositor();
return style->shouldCompositeForCurrentAnimations();
}
bool CompositingReasonFinder::requiresCompositingForPositionFixed(RenderObject* renderer, const RenderLayer* layer, RenderLayer::ViewportConstrainedNotCompositedReason* viewportConstrainedNotCompositedReason) 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.
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)
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;
}
}
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