1 // Copyright 2014 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "config.h" 6 #include "core/rendering/compositing/CompositingReasonFinder.h" 7 8 #include "core/CSSPropertyNames.h" 9 #include "core/dom/Document.h" 10 #include "core/frame/FrameView.h" 11 #include "core/frame/Settings.h" 12 #include "core/page/Page.h" 13 #include "core/rendering/RenderView.h" 14 #include "core/rendering/compositing/RenderLayerCompositor.h" 15 16 namespace blink { 17 CompositingReasonFinder(RenderView & renderView)18CompositingReasonFinder::CompositingReasonFinder(RenderView& renderView) 19 : m_renderView(renderView) 20 , m_compositingTriggers(static_cast<CompositingTriggerFlags>(AllCompositingTriggers)) 21 { 22 updateTriggers(); 23 } 24 updateTriggers()25void CompositingReasonFinder::updateTriggers() 26 { 27 m_compositingTriggers = 0; 28 29 Settings& settings = m_renderView.document().page()->settings(); 30 if (settings.preferCompositingToLCDTextEnabled()) { 31 m_compositingTriggers |= ScrollableInnerFrameTrigger; 32 m_compositingTriggers |= OverflowScrollTrigger; 33 m_compositingTriggers |= ViewportConstrainedPositionedTrigger; 34 } 35 } 36 hasOverflowScrollTrigger() const37bool CompositingReasonFinder::hasOverflowScrollTrigger() const 38 { 39 return m_compositingTriggers & OverflowScrollTrigger; 40 } 41 isMainFrame() const42bool CompositingReasonFinder::isMainFrame() const 43 { 44 // FIXME: LocalFrame::isMainFrame() is probably better. 45 return !m_renderView.document().ownerElement(); 46 } 47 directReasons(const RenderLayer * layer) const48CompositingReasons CompositingReasonFinder::directReasons(const RenderLayer* layer) const 49 { 50 ASSERT(potentialCompositingReasonsFromStyle(layer->renderer()) == layer->potentialCompositingReasonsFromStyle()); 51 CompositingReasons styleDeterminedDirectCompositingReasons = layer->potentialCompositingReasonsFromStyle() & CompositingReasonComboAllDirectStyleDeterminedReasons; 52 return styleDeterminedDirectCompositingReasons | nonStyleDeterminedDirectReasons(layer); 53 } 54 55 // This information doesn't appear to be incorporated into CompositingReasons. requiresCompositingForScrollableFrame() const56bool CompositingReasonFinder::requiresCompositingForScrollableFrame() const 57 { 58 // Need this done first to determine overflow. 59 ASSERT(!m_renderView.needsLayout()); 60 if (isMainFrame()) 61 return false; 62 63 if (!(m_compositingTriggers & ScrollableInnerFrameTrigger)) 64 return false; 65 66 return m_renderView.frameView()->isScrollable(); 67 } 68 potentialCompositingReasonsFromStyle(RenderObject * renderer) const69CompositingReasons CompositingReasonFinder::potentialCompositingReasonsFromStyle(RenderObject* renderer) const 70 { 71 CompositingReasons reasons = CompositingReasonNone; 72 73 RenderStyle* style = renderer->style(); 74 75 if (requiresCompositingForTransform(renderer)) 76 reasons |= CompositingReason3DTransform; 77 78 if (style->backfaceVisibility() == BackfaceVisibilityHidden) 79 reasons |= CompositingReasonBackfaceVisibilityHidden; 80 81 if (requiresCompositingForAnimation(style)) 82 reasons |= CompositingReasonActiveAnimation; 83 84 if (style->hasWillChangeCompositingHint() && !style->subtreeWillChangeContents()) 85 reasons |= CompositingReasonWillChangeCompositingHint; 86 87 if (style->hasInlineTransform()) 88 reasons |= CompositingReasonInlineTransform; 89 90 if (style->transformStyle3D() == TransformStyle3DPreserve3D) 91 reasons |= CompositingReasonPreserve3DWith3DDescendants; 92 93 if (style->hasPerspective()) 94 reasons |= CompositingReasonPerspectiveWith3DDescendants; 95 96 // If the implementation of createsGroup changes, we need to be aware of that in this part of code. 97 ASSERT((renderer->isTransparent() || renderer->hasMask() || renderer->hasFilter() || renderer->hasBlendMode()) == renderer->createsGroup()); 98 99 if (style->hasMask()) 100 reasons |= CompositingReasonMaskWithCompositedDescendants; 101 102 if (style->hasFilter()) 103 reasons |= CompositingReasonFilterWithCompositedDescendants; 104 105 // See RenderLayer::updateTransform for an explanation of why we check both. 106 if (renderer->hasTransform() && style->hasTransform()) 107 reasons |= CompositingReasonTransformWithCompositedDescendants; 108 109 if (renderer->isTransparent()) 110 reasons |= CompositingReasonOpacityWithCompositedDescendants; 111 112 if (renderer->hasBlendMode()) 113 reasons |= CompositingReasonBlendingWithCompositedDescendants; 114 115 if (renderer->hasReflection()) 116 reasons |= CompositingReasonReflectionWithCompositedDescendants; 117 118 ASSERT(!(reasons & ~CompositingReasonComboAllStyleDeterminedReasons)); 119 return reasons; 120 } 121 requiresCompositingForTransform(RenderObject * renderer) const122bool CompositingReasonFinder::requiresCompositingForTransform(RenderObject* renderer) const 123 { 124 // Note that we ask the renderer if it has a transform, because the style may have transforms, 125 // but the renderer may be an inline that doesn't suppport them. 126 return renderer->hasTransform() && renderer->style()->transform().has3DOperation(); 127 } 128 nonStyleDeterminedDirectReasons(const RenderLayer * layer) const129CompositingReasons CompositingReasonFinder::nonStyleDeterminedDirectReasons(const RenderLayer* layer) const 130 { 131 CompositingReasons directReasons = CompositingReasonNone; 132 RenderObject* renderer = layer->renderer(); 133 134 if (hasOverflowScrollTrigger()) { 135 if (layer->clipParent()) 136 directReasons |= CompositingReasonOutOfFlowClipping; 137 138 if (const RenderLayer* scrollingAncestor = layer->ancestorScrollingLayer()) { 139 if (scrollingAncestor->needsCompositedScrolling() && layer->scrollParent()) 140 directReasons |= CompositingReasonOverflowScrollingParent; 141 } 142 143 if (layer->needsCompositedScrolling()) 144 directReasons |= CompositingReasonOverflowScrollingTouch; 145 } 146 147 if (requiresCompositingForPositionFixed(layer)) 148 directReasons |= CompositingReasonPositionFixed; 149 150 directReasons |= renderer->additionalCompositingReasons(); 151 152 ASSERT(!(directReasons & CompositingReasonComboAllStyleDeterminedReasons)); 153 return directReasons; 154 } 155 requiresCompositingForAnimation(RenderStyle * style) const156bool CompositingReasonFinder::requiresCompositingForAnimation(RenderStyle* style) const 157 { 158 if (style->subtreeWillChangeContents()) 159 return style->isRunningAnimationOnCompositor(); 160 161 return style->shouldCompositeForCurrentAnimations(); 162 } 163 requiresCompositingForPositionFixed(const RenderLayer * layer) const164bool CompositingReasonFinder::requiresCompositingForPositionFixed(const RenderLayer* layer) const 165 { 166 if (!(m_compositingTriggers & ViewportConstrainedPositionedTrigger)) 167 return false; 168 // Don't promote fixed position elements that are descendants of a non-view container, e.g. transformed elements. 169 // They will stay fixed wrt the container rather than the enclosing frame. 170 return layer->scrollsWithViewport() && m_renderView.frameView()->isScrollable(); 171 } 172 173 } 174