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Issue 190973007:
Reland "Avoid layout/full-repaint on view height change if possible" (Closed)
Base URL: https://chromium.googlesource.com/chromium/blink.git@master| Index: Source/core/rendering/RenderView.cpp |
| diff --git a/Source/core/rendering/RenderView.cpp b/Source/core/rendering/RenderView.cpp |
| index 04eea08abaaf75c9f57665d7ec67d087b70ad1eb..ead2bdeca2936d5f00033132028ae2d42ad3c989 100644 |
| --- a/Source/core/rendering/RenderView.cpp |
| +++ b/Source/core/rendering/RenderView.cpp |
| @@ -997,4 +997,83 @@ double RenderView::layoutViewportHeight() const |
| return viewHeight(IncludeScrollbars) / scale; |
| } |
| +bool RenderView::trySimplifiedLayoutOnHeightChange() |
| +{ |
| + // FIXME: Move logics that are generic to RenderBox or RenderBlock into these classes |
| + // so that this function can be also used to optimize layout of them. |
| + |
| + // The style must be up-to-date. |
| + ASSERT(!document().needsStyleRecalc() && !document().childNeedsStyleRecalc()); |
| + |
| + // Don't need to check viewport media queries or viewport sizes here, because they are |
| + // handled before and during style recalc which should happen before this function is called. |
| + |
| + // Quicks mode has different layout rules on view size change, e.g. the height of <body> and |
| + // percent height descendants etc. To avoid simplified layout from being too complex, fallback |
| + // to full layout. |
| + if (document().inQuirksMode()) |
| + return false; |
| + |
| + if (document().paginated() || shouldUsePrintingLayout()) |
| + return false; |
| + |
| + // If the height is decreasing and the view isn't vertically scrollable, fallback to |
| + // full layout to calculate the new layout overflow rect. |
| + LayoutRect layoutOverflow = layoutOverflowRect(); |
| + if (layoutOverflow.maxY() <= noOverflowRect().maxY() && viewHeight() < height()) |
| + return false; |
| + |
| + // Update style to ensure the following checks to access up-to-date styles. |
| + document().updateStyleIfNeeded(); |
|
Julien - ping for review
2014/03/11 01:23:37
Isn't this line contrary with the ASSERT above abo
Xianzhu
2014/03/11 19:05:13
Sorry. I added the code and later meant to move th
|
| + if (needsLayout()) |
| + return false; |
| + |
| + // Optimize layout in horizontal writing mode only to simplify the logic. |
| + if (!style()->isHorizontalWritingMode()) |
| + return false; |
| + |
| + if (hasPercentHeightDescendants()) |
| + return false; |
| + |
| + // Needs full layout if there is no body element (e.g. there is frameset whose layout is almost always |
| + // affected by the view size. |
| + Element* body = document().body(); |
| + if (!body || !body->hasTagName(HTMLNames::bodyTag)) |
| + return false; |
| + |
| + // Root background image may be stretched related to the viewport size. |
| + Element* documentElement = document().documentElement(); |
| + if (!documentElement || !documentElement->renderer() |
| + || documentElement->renderer()->rendererForRootBackground()->style()->hasBackgroundImage()) |
| + return false; |
| + |
| + if (TrackedRendererListHashSet* positionedObjects = this->positionedObjects()) { |
| + TrackedRendererListHashSet::iterator end = positionedObjects->end(); |
| + for (TrackedRendererListHashSet::iterator it = positionedObjects->begin(); it != end; ++it) { |
| + if ((*it)->node() && (*it)->node()->hasTagName(HTMLNames::dialogTag)) |
| + return false; |
| + |
| + RenderStyle* childStyle = (*it)->style(); |
| + // Fixed position element may change compositing state when viewport height changes. |
| + if (childStyle->position() == FixedPosition) |
| + return false; |
|
Xianzhu
2014/03/11 19:05:13
Removed the above because fixed position layout ha
|
| + if (childStyle->top().isPercent() || childStyle->height().isPercent() || childStyle->minHeight().isPercent() || childStyle->maxHeight().isPercent() || !childStyle->bottom().isAuto()) |
| + return false; |
| + } |
| + } |
| + |
| + // Do a simplified layout on height change. |
| + setHeight(viewHeight()); |
| + |
| + // During a normal layout, change of height may cause creating or destroying the overflow. |
| + // The following code mimics the normal layout for overflow. |
| + m_overflow.clear(); |
| + addLayoutOverflow(layoutOverflow); |
|
Julien - ping for review
2014/03/11 01:23:37
It's weird that you don't also add visual overflow
Xianzhu
2014/03/11 19:05:13
Actually I didn't notice it, so for cases needing
|
| + |
| + // FIXME: There may be a more efficient way to adjust the size of the root layer. |
| + layer()->updateLayerPositionsAfterLayout(layer(), RenderLayer::defaultFlags); |
|
Julien - ping for review
2014/03/11 01:23:37
updateLayerPositions will recurse into all the lay
Xianzhu
2014/03/11 19:05:13
The repaints caused by layer resizing and exposing
|
| + |
| + return true; |
| +} |
| + |
| } // namespace WebCore |
