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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 "core/layout/compositing/CompositingReasonFinder.h"
#include "core/CSSPropertyNames.h"
#include "core/dom/Document.h"
#include "core/frame/FrameView.h"
#include "core/frame/Settings.h"
#include "core/layout/LayoutView.h"
#include "core/page/Page.h"
#include "core/paint/PaintLayer.h"
namespace blink {
CompositingReasonFinder::CompositingReasonFinder(LayoutView& layoutView)
: m_layoutView(layoutView),
m_compositingTriggers(
static_cast<CompositingTriggerFlags>(AllCompositingTriggers)) {
updateTriggers();
}
void CompositingReasonFinder::updateTriggers() {
m_compositingTriggers = 0;
Settings& settings = m_layoutView.document().page()->settings();
if (settings.getPreferCompositingToLCDTextEnabled()) {
m_compositingTriggers |= ScrollableInnerFrameTrigger;
m_compositingTriggers |= OverflowScrollTrigger;
m_compositingTriggers |= ViewportConstrainedPositionedTrigger;
}
}
bool CompositingReasonFinder::isMainFrame() const {
return m_layoutView.document().isInMainFrame();
}
CompositingReasons CompositingReasonFinder::directReasons(
const PaintLayer* layer) const {
if (RuntimeEnabledFeatures::slimmingPaintV2Enabled())
return CompositingReasonNone;
DCHECK_EQ(potentialCompositingReasonsFromStyle(layer->layoutObject()),
layer->potentialCompositingReasonsFromStyle());
CompositingReasons styleDeterminedDirectCompositingReasons =
layer->potentialCompositingReasonsFromStyle() &
CompositingReasonComboAllDirectStyleDeterminedReasons;
return styleDeterminedDirectCompositingReasons |
nonStyleDeterminedDirectReasons(layer);
}
// This information doesn't appear to be incorporated into CompositingReasons.
bool CompositingReasonFinder::requiresCompositingForScrollableFrame() const {
// Need this done first to determine overflow.
DCHECK(!m_layoutView.needsLayout());
if (isMainFrame())
return false;
if (!(m_compositingTriggers & ScrollableInnerFrameTrigger))
return false;
return m_layoutView.frameView()->isScrollable();
}
CompositingReasons
CompositingReasonFinder::potentialCompositingReasonsFromStyle(
LayoutObject* layoutObject) const {
if (RuntimeEnabledFeatures::slimmingPaintV2Enabled())
return CompositingReasonNone;
CompositingReasons reasons = CompositingReasonNone;
const ComputedStyle& style = layoutObject->styleRef();
if (requiresCompositingForTransform(*layoutObject))
reasons |= CompositingReason3DTransform;
if (style.backfaceVisibility() == BackfaceVisibilityHidden)
reasons |= CompositingReasonBackfaceVisibilityHidden;
if (requiresCompositingForAnimation(style))
reasons |= CompositingReasonActiveAnimation;
if (style.hasWillChangeCompositingHint() &&
!style.subtreeWillChangeContents())
reasons |= CompositingReasonWillChangeCompositingHint;
if (style.hasInlineTransform())
reasons |= CompositingReasonInlineTransform;
if (style.usedTransformStyle3D() == TransformStyle3DPreserve3D)
reasons |= CompositingReasonPreserve3DWith3DDescendants;
if (style.hasPerspective())
reasons |= CompositingReasonPerspectiveWith3DDescendants;
if (style.hasCompositorProxy())
reasons |= CompositingReasonCompositorProxy;
// If the implementation of createsGroup changes, we need to be aware of that
// in this part of code.
DCHECK((layoutObject->isTransparent() || layoutObject->hasMask() ||
layoutObject->hasFilterInducingProperty() || style.hasBlendMode()) ==
layoutObject->createsGroup());
if (style.hasMask())
reasons |= CompositingReasonMaskWithCompositedDescendants;
if (style.hasFilterInducingProperty())
reasons |= CompositingReasonFilterWithCompositedDescendants;
if (style.hasBackdropFilter())
reasons |= CompositingReasonBackdropFilter;
// See Layer::updateTransform for an explanation of why we check both.
if (layoutObject->hasTransformRelatedProperty() && style.hasTransform())
reasons |= CompositingReasonTransformWithCompositedDescendants;
if (layoutObject->isTransparent())
reasons |= CompositingReasonOpacityWithCompositedDescendants;
if (style.hasBlendMode())
reasons |= CompositingReasonBlendingWithCompositedDescendants;
if (layoutObject->hasReflection())
reasons |= CompositingReasonReflectionWithCompositedDescendants;
DCHECK(!(reasons & ~CompositingReasonComboAllStyleDeterminedReasons));
return reasons;
}
bool CompositingReasonFinder::requiresCompositingForTransform(
const LayoutObject& layoutObject) {
// Note that we ask the layoutObject if it has a transform, because the style
// may have transforms, but the layoutObject may be an inline that doesn't
// support them.
return layoutObject.hasTransformRelatedProperty() &&
layoutObject.styleRef().has3DTransform();
}
CompositingReasons CompositingReasonFinder::nonStyleDeterminedDirectReasons(
const PaintLayer* layer) const {
CompositingReasons directReasons = CompositingReasonNone;
LayoutObject* layoutObject = layer->layoutObject();
if (m_compositingTriggers & OverflowScrollTrigger && layer->clipParent())
directReasons |= CompositingReasonOutOfFlowClipping;
if (layer->needsCompositedScrolling())
directReasons |= CompositingReasonOverflowScrollingTouch;
// Composite |layer| if it is inside of an ancestor scrolling layer, but that
// scrolling layer is not on the stacking context ancestor chain of |layer|.
// See the definition of the scrollParent property in Layer for more detail.
if (const PaintLayer* scrollingAncestor = layer->ancestorScrollingLayer()) {
if (scrollingAncestor->needsCompositedScrolling() && layer->scrollParent())
directReasons |= CompositingReasonOverflowScrollingParent;
}
// TODO(flackr): Rename functions and variables to include sticky position
// (i.e. ScrollDependentPosition rather than PositionFixed).
if (requiresCompositingForScrollDependentPosition(layer))
directReasons |= CompositingReasonScrollDependentPosition;
directReasons |= layoutObject->additionalCompositingReasons();
DCHECK(!(directReasons & CompositingReasonComboAllStyleDeterminedReasons));
return directReasons;
}
bool CompositingReasonFinder::requiresCompositingForAnimation(
const ComputedStyle& style) {
if (style.subtreeWillChangeContents())
return style.isRunningAnimationOnCompositor();
return style.shouldCompositeForCurrentAnimations();
}
bool CompositingReasonFinder::requiresCompositingForEffectAnimation(
const ComputedStyle& style) {
if (style.subtreeWillChangeContents()) {
return style.isRunningOpacityAnimationOnCompositor() ||
style.isRunningFilterAnimationOnCompositor() ||
style.isRunningBackdropFilterAnimationOnCompositor();
}
return style.hasCurrentOpacityAnimation() ||
style.hasCurrentFilterAnimation() ||
style.hasCurrentBackdropFilterAnimation();
}
bool CompositingReasonFinder::requiresCompositingForTransformAnimation(
const ComputedStyle& style) {
return style.subtreeWillChangeContents()
? style.isRunningTransformAnimationOnCompositor()
: style.hasCurrentTransformAnimation();
}
bool CompositingReasonFinder::requiresCompositingForScrollDependentPosition(
const PaintLayer* layer) const {
if (layer->layoutObject()->style()->position() != FixedPosition &&
layer->layoutObject()->style()->position() != StickyPosition)
return false;
if (!(m_compositingTriggers & ViewportConstrainedPositionedTrigger) &&
(!RuntimeEnabledFeatures::compositeOpaqueFixedPositionEnabled() ||
!layer->backgroundIsKnownToBeOpaqueInRect(
LayoutRect(layer->boundingBoxForCompositing())) ||
layer->compositesWithTransform() || layer->compositesWithOpacity())) {
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 (layer->sticksToViewport())
return m_layoutView.frameView()->isScrollable();
return layer->layoutObject()->style()->position() == StickyPosition &&
layer->ancestorOverflowLayer()->scrollsOverflow();
}
} // namespace blink
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