Address TODOs in the new layer painting and hit testing.

sky/engine/core/rendering/RenderBox.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 464 matching lines @@
 
     LayoutRect localHitTestRect = hitTestRect;
     HitTestLocation localHitTestLocation = hitTestLocation;
 
     // We need transform state for the first time, or to offset the container state, or to accumulate the new transform.
     if (layer()->transform() || transformState || layer()->has3DTransformedDescendant() || layer()->preserves3D())
         localTransformState = createLocalTransformState(rootLayer, containerLayer, localHitTestRect, localHitTestLocation, transformState);
 
     // Apply a transform if we have one.
     if (layer()->transform()) {
+        // The RenderView cannot have transforms.
+        ASSERT(parent());
         // Make sure the parent's clip rects have been calculated.
-        if (parent()) {
-            ClipRect clipRect = layer()->clipper().backgroundClipRect(ClipRectsContext(rootLayer, RootRelativeClipRects));
-            // Go ahead and test the enclosing clip now.
-            if (!clipRect.intersects(localHitTestLocation))
-                return 0;
-        }
+        ClipRect clipRect = layer()->clipper().backgroundClipRect(ClipRectsContext(rootLayer, RootRelativeClipRects));
+        // Go ahead and test the enclosing clip now.
+        if (!clipRect.intersects(localHitTestLocation))
+            return 0;
 
         // If the transform can't be inverted, then don't hit test this layer at all.
         if (!localTransformState->m_accumulatedTransform.isInvertible())
             return 0;
 
         // Compute the point and the hit test rect in the coords of this layer by using the values
         // from the transformState, which store the point and quad in the coords of the last flattened
         // layer, and the accumulated transform which lets up map through preserve-3d layers.
         //
         // We can't just map hitTestLocation and hitTestRect because they may have been flattened (losing z)
@@ skipping 147 matching lines @@
     if (!opacity())
         return;
 
     LayerPaintingInfo paintingInfo(rootLayer, rect, LayoutSize());
 
     if (!layer()->paintsWithTransform()) {
         paintLayerContents(context, paintingInfo, rect);
         return;
     }
 
+    // The RenderView can't be transformed in Sky.
+    ASSERT(layer()->parent());
+
     TransformationMatrix layerTransform = layer()->renderableTransform();
     // If the transform can't be inverted, then don't paint anything.
     if (!layerTransform.isInvertible())
         return;
 
     // If we have a transparency layer enclosing us and we are the root of a transform, then we need to establish the transparency
     // layer from the parent now, assuming there is a parent
     if (layer()->isTransparent()) {
         // TODO(ojan): This should ASSERT(layer()->parent()) instead of branching since the
         // RenderView can't be transformed in sky.
         if (layer()->parent())
             layer()->parent()->beginTransparencyLayers(context, paintingInfo.rootLayer, paintingInfo.paintDirtyRect, paintingInfo.subPixelAccumulation);
         else
             layer()->beginTransparencyLayers(context, paintingInfo.rootLayer, paintingInfo.paintDirtyRect, paintingInfo.subPixelAccumulation);
     }
 
     // Make sure the parent's clip rects have been calculated.
-    ClipRect clipRect;
-    // TODO(ojan): This should ASSERT(layer()->parent()) instead of branching since the
-    // RenderView can't be transformed in sky.
-    if (layer()->parent()) {
-        ClipRectsContext clipRectsContext(paintingInfo.rootLayer, PaintingClipRects);
-        clipRect = layer()->clipper().backgroundClipRect(clipRectsContext);
-        clipRect.intersect(paintingInfo.paintDirtyRect);
+    ClipRectsContext clipRectsContext(paintingInfo.rootLayer, PaintingClipRects);
+    ClipRect clipRect = layer()->clipper().backgroundClipRect(clipRectsContext);
+    clipRect.intersect(paintingInfo.paintDirtyRect);
 
-        // Push the parent coordinate space's clip.
-        layer()->parent()->clipToRect(paintingInfo, context, clipRect);
-    }
+    // Push the parent coordinate space's clip.
+    layer()->parent()->clipToRect(paintingInfo, context, clipRect);
 
     // This involves subtracting out the position of the layer in our current coordinate space, but preserving
     // the accumulated error for sub-pixel layout.
     LayoutPoint delta;
     layer()->convertToLayerCoords(paintingInfo.rootLayer, delta);
     TransformationMatrix transform(layer()->renderableTransform());
     IntPoint roundedDelta = roundedIntPoint(delta);
     transform.translateRight(roundedDelta.x(), roundedDelta.y());
     LayoutSize adjustedSubPixelAccumulation = paintingInfo.subPixelAccumulation + (delta - roundedDelta);
 
     // Apply the transform.
     GraphicsContextStateSaver stateSaver(*context, false);
     if (!transform.isIdentity()) {
         stateSaver.save();
         context->concatCTM(transform.toAffineTransform());
     }
 
     // Now do a paint with the root layer shifted to be us.
     LayerPaintingInfo transformedPaintingInfo(layer(), enclosingIntRect(transform.inverse().mapRect(paintingInfo.paintDirtyRect)),
         adjustedSubPixelAccumulation);
     paintLayerContents(context, transformedPaintingInfo, rect);
 
     // Restore the clip.
-    // TODO(ojan): This should ASSERT(layer()->parent()) instead of branching since the
-    // RenderView can't be transformed in sky.
-    if (layer()->parent())
-        layer()->parent()->restoreClip(context, paintingInfo.paintDirtyRect, clipRect);
+    layer()->parent()->restoreClip(context, paintingInfo.paintDirtyRect, clipRect);
 }
 
 void RenderBox::paintLayerContents(GraphicsContext* context, const LayerPaintingInfo& paintingInfo, const IntRect& rect)
 {
     float deviceScaleFactor = blink::deviceScaleFactor(frame());
     context->setDeviceScaleFactor(deviceScaleFactor);
 
     GraphicsContext* transparencyLayerContext = context;
 
     LayoutPoint offsetFromRoot;
     layer()->convertToLayerCoords(paintingInfo.rootLayer, offsetFromRoot);
 
+    LayerPaintingInfo localPaintingInfo(paintingInfo);
+
+    LayoutRect layerBounds;
+    // FIXME(sky): Remove foregroundRect. It's unused.
+    ClipRect contentRect, foregroundRect;
+    ClipRectsContext clipRectsContext(localPaintingInfo.rootLayer, PaintingClipRects, localPaintingInfo.subPixelAccumulation);
+    layer()->clipper().calculateRects(clipRectsContext, localPaintingInfo.paintDirtyRect,
+        layerBounds, contentRect, foregroundRect,
+        &offsetFromRoot);
+
+    if (!layer()->intersectsDamageRect(layerBounds, contentRect.rect(), localPaintingInfo.rootLayer, &offsetFromRoot))
+        return;
+
     LayoutRect rootRelativeBounds;
     bool rootRelativeBoundsComputed = false;
 
     // Apply clip-path to context.
     GraphicsContextStateSaver clipStateSaver(*context, false);
 
     // Clip-path, like border radius, must not be applied to the contents of a composited-scrolling container.
     // It must, however, still be applied to the mask layer, so that the compositor can properly mask the
     // scrolling contents and scrollbars.
-    // TODO(ojan): This style null check doesn't make sense. We should always have a style.
-    if (hasClipPath() && style()) {
+    if (hasClipPath()) {
         ASSERT(style()->clipPath());
         if (style()->clipPath()->type() == ClipPathOperation::SHAPE) {
             ShapeClipPathOperation* clipPath = toShapeClipPathOperation(style()->clipPath());
             if (clipPath->isValid()) {
                 clipStateSaver.save();
 
                 if (!rootRelativeBoundsComputed) {
                     rootRelativeBounds = layer()->physicalBoundingBoxIncludingReflectionAndStackingChildren(paintingInfo.rootLayer, offsetFromRoot);
                     rootRelativeBoundsComputed = true;
                 }
 
                 context->clipPath(clipPath->path(rootRelativeBounds), clipPath->windRule());
             }
         }
     }
 
-    LayerPaintingInfo localPaintingInfo(paintingInfo);
+    bool haveTransparency = layer()->isTransparent();
+
     FilterEffectRendererHelper filterPainter(layer()->filterRenderer() && layer()->paintsWithFilters());
 
-    LayoutRect layerBounds;
-    // FIXME(sky): Remove foregroundRect. It's unused.
-    ClipRect contentRect, foregroundRect;
-    ClipRectsContext clipRectsContext(localPaintingInfo.rootLayer, PaintingClipRects, localPaintingInfo.subPixelAccumulation);
-    layer()->clipper().calculateRects(clipRectsContext, localPaintingInfo.paintDirtyRect,
-        layerBounds, contentRect, foregroundRect,
-        &offsetFromRoot);
-
-    bool shouldPaintContent = layer()->intersectsDamageRect(layerBounds, contentRect.rect(), localPaintingInfo.rootLayer, &offsetFromRoot);
-
-    bool haveTransparency = layer()->isTransparent();
-
     if (filterPainter.haveFilterEffect()) {
         ASSERT(layer()->filterInfo());
 
         if (!rootRelativeBoundsComputed)
             rootRelativeBounds = layer()->physicalBoundingBoxIncludingReflectionAndStackingChildren(paintingInfo.rootLayer, offsetFromRoot);
 
         if (filterPainter.prepareFilterEffect(layer(), rootRelativeBounds, paintingInfo.paintDirtyRect)) {
             // Rewire the old context to a memory buffer, so that we can capture the contents of the layer.
             // NOTE: We saved the old context in the "transparencyLayerContext" local variable, to be able to start a transparency layer
             // on the original context and avoid duplicating "beginFilterEffect" after each transparency layer call. Also, note that
@@ skipping 12 matching lines @@
             // Subsequent code should not clip to the dirty rect, since we've already
             // done it above, and doing it later will defeat the outsets.
             localPaintingInfo.clipToDirtyRect = false;
 
             context = filterPainter.beginFilterEffect(context);
         }
     }
 
     LayoutPoint layerLocation = toPoint(layerBounds.location() - location() + localPaintingInfo.subPixelAccumulation);
 
-    if (shouldPaintContent) {
-        bool contentRectIsEmpty = contentRect.isEmpty();
+    // Begin transparency if we have something to paint.
+    if (haveTransparency)
+        layer()->beginTransparencyLayers(transparencyLayerContext, localPaintingInfo.rootLayer, paintingInfo.paintDirtyRect, localPaintingInfo.subPixelAccumulation);
 
-        // Begin transparency if we have something to paint.
-        if (haveTransparency && !contentRectIsEmpty)
-            layer()->beginTransparencyLayers(transparencyLayerContext, localPaintingInfo.rootLayer, paintingInfo.paintDirtyRect, localPaintingInfo.subPixelAccumulation);
+    if (localPaintingInfo.clipToDirtyRect)
+        layer()->clipToRect(localPaintingInfo, context, contentRect);
 
-        // Optimize clipping for the single fragment case.
-        bool shouldClip = localPaintingInfo.clipToDirtyRect && !contentRectIsEmpty;
-        if (shouldClip)
-            layer()->clipToRect(localPaintingInfo, context, contentRect);
+    Vector<RenderBox*> layers;
+    PaintInfo paintInfo(context, pixelSnappedIntRect(contentRect.rect()), localPaintingInfo.rootLayer->renderer());
+    paint(paintInfo, layerLocation, layers);
 
-        // TODO(ojan): We probably should have already set shouldPaintContent to false if the rect is empty.
-        if (!contentRectIsEmpty) {
-            Vector<RenderBox*> layers;
+    std::stable_sort(layers.begin(), layers.end(), forwardCompareZIndex);
+    for (auto& box : layers) {
+        box->paintLayer(context, paintingInfo.rootLayer, rect);
+    }
 
-            PaintInfo paintInfo(context, pixelSnappedIntRect(contentRect.rect()), localPaintingInfo.rootLayer->renderer());
-            paint(paintInfo, layerLocation, layers);
-
-            std::stable_sort(layers.begin(), layers.end(), forwardCompareZIndex);
-            for (auto& box : layers) {
-                box->paintLayer(context, paintingInfo.rootLayer, rect);
-            }
-        }
-
-        if (shouldClip)
-            layer()->restoreClip(context, localPaintingInfo.paintDirtyRect, contentRect);
-    }
+    if (localPaintingInfo.clipToDirtyRect)
+        layer()->restoreClip(context, localPaintingInfo.paintDirtyRect, contentRect);
 
     if (filterPainter.hasStartedFilterEffect()) {
         context = filterPainter.applyFilterEffect();
         layer()->restoreClip(transparencyLayerContext, localPaintingInfo.paintDirtyRect, contentRect);
     }
 
     // Make sure that we now use the original transparency context.
     ASSERT(transparencyLayerContext == context);
 
     // End our transparency layer
@@ skipping 2197 matching lines @@
 
 RenderBox::BoxDecorationData::BoxDecorationData(const RenderStyle& style)
 {
     backgroundColor = style.colorIncludingFallback(CSSPropertyBackgroundColor);
     hasBackground = backgroundColor.alpha() || style.hasBackgroundImage();
     ASSERT(hasBackground == style.hasBackground());
     hasBorder = style.hasBorder();
 }
 
 } // namespace blink