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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/CSSPropertyNames.h"
#include "core/dom/Document.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 blink {
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.preferCompositingToLCDTextEnabled()) {
m_compositingTriggers |= ScrollableInnerFrameTrigger;
m_compositingTriggers |= OverflowScrollTrigger;
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
{
ASSERT(potentialCompositingReasonsFromStyle(layer->renderer()) == 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.
ASSERT(!m_renderView.needsLayout());
if (isMainFrame())
return false;
if (!(m_compositingTriggers & ScrollableInnerFrameTrigger))
return false;
return m_renderView.frameView()->isScrollable();
}
CompositingReasons CompositingReasonFinder::potentialCompositingReasonsFromStyle(RenderObject* renderer) const
{
CompositingReasons reasons = CompositingReasonNone;
RenderStyle* style = renderer->style();
if (requiresCompositingForTransform(renderer))
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->transformStyle3D() == TransformStyle3DPreserve3D)
reasons |= CompositingReasonPreserve3DWith3DDescendants;
if (style->hasPerspective())
reasons |= CompositingReasonPerspectiveWith3DDescendants;
// If the implementation of createsGroup changes, we need to be aware of that in this part of code.
ASSERT((renderer->isTransparent() || renderer->hasMask() || renderer->hasFilter() || style->hasBlendMode()) == renderer->createsGroup());
if (style->hasMask())
reasons |= CompositingReasonMaskWithCompositedDescendants;
if (style->hasFilter())
reasons |= CompositingReasonFilterWithCompositedDescendants;
// See RenderLayer::updateTransform for an explanation of why we check both.
if (renderer->hasTransformRelatedProperty() && style->hasTransform())
reasons |= CompositingReasonTransformWithCompositedDescendants;
if (renderer->isTransparent())
reasons |= CompositingReasonOpacityWithCompositedDescendants;
if (style->hasBlendMode())
reasons |= CompositingReasonBlendingWithCompositedDescendants;
if (renderer->hasReflection())
reasons |= CompositingReasonReflectionWithCompositedDescendants;
ASSERT(!(reasons & ~CompositingReasonComboAllStyleDeterminedReasons));
return reasons;
}
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->hasTransformRelatedProperty() && renderer->style()->transform().has3DOperation();
}
CompositingReasons CompositingReasonFinder::nonStyleDeterminedDirectReasons(const RenderLayer* layer) const
{
CompositingReasons directReasons = CompositingReasonNone;
RenderObject* renderer = layer->renderer();
if (hasOverflowScrollTrigger()) {
if (layer->clipParent())
directReasons |= CompositingReasonOutOfFlowClipping;
if (const RenderLayer* scrollingAncestor = layer->ancestorScrollingLayer()) {
if (scrollingAncestor->needsCompositedScrolling() && layer->scrollParent())
directReasons |= CompositingReasonOverflowScrollingParent;
}
if (layer->needsCompositedScrolling())
directReasons |= CompositingReasonOverflowScrollingTouch;
}
if (requiresCompositingForPositionFixed(layer))
directReasons |= CompositingReasonPositionFixed;
directReasons |= renderer->additionalCompositingReasons();
ASSERT(!(directReasons & CompositingReasonComboAllStyleDeterminedReasons));
return directReasons;
}
bool CompositingReasonFinder::requiresCompositingForAnimation(RenderStyle* style) const
{
if (style->subtreeWillChangeContents())
return style->isRunningAnimationOnCompositor();
return style->shouldCompositeForCurrentAnimations();
}
bool CompositingReasonFinder::requiresCompositingForPositionFixed(const RenderLayer* layer) const
{
if (!(m_compositingTriggers & ViewportConstrainedPositionedTrigger))
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.
return layer->scrollsWithViewport() && m_renderView.frameView()->isScrollable();
}
}
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