C++ PaintLayer::needsCompositedScrolling方法代码示例

TEST_F(PaintLayerScrollableAreaTest, OpaqueLayersPromotedOnStyleChange) {
  RuntimeEnabledFeatures::setCompositeOpaqueScrollersEnabled(true);

  setBodyInnerHTML(
      "<style>"
      "#scroller { overflow: scroll; height: 200px; width: 200px; background: "
      "rgba(255,255,255,0.5) local content-box; }"
      "#scrolled { height: 300px; }"
      "</style>"
      "<div id=\"scroller\"><div id=\"scrolled\"></div></div>");
  document().view()->updateAllLifecyclePhases();

  EXPECT_TRUE(RuntimeEnabledFeatures::compositeOpaqueScrollersEnabled());
  Element* scroller = document().getElementById("scroller");
  PaintLayer* paintLayer =
      toLayoutBoxModelObject(scroller->layoutObject())->layer();
  ASSERT_TRUE(paintLayer);
  EXPECT_FALSE(paintLayer->needsCompositedScrolling());

  // Change the background to transparent
  scroller->setAttribute(HTMLNames::styleAttr,
                         "background: white local content-box;");
  document().view()->updateAllLifecyclePhases();
  paintLayer = toLayoutBoxModelObject(scroller->layoutObject())->layer();
  ASSERT_TRUE(paintLayer);
  EXPECT_TRUE(paintLayer->needsCompositedScrolling());
  EXPECT_TRUE(paintLayer->graphicsLayerBacking());
  ASSERT_TRUE(paintLayer->graphicsLayerBackingForScrolling());
  EXPECT_TRUE(paintLayer->graphicsLayerBackingForScrolling()->contentsOpaque());
}

// Test that opacity applied to the scroller or an ancestor will cause the
// scrolling contents layer to not be promoted.
TEST_F(PaintLayerScrollableAreaTest, OnlyOpaqueLayersPromoted) {
  ScopedCompositeOpaqueScrollersForTest compositeOpaqueScrollers(true);

  setBodyInnerHTML(
      "<style>"
      "#scroller { overflow: scroll; height: 200px; width: 200px; background: "
      "white local content-box; }"
      "#scrolled { height: 300px; }"
      "</style>"
      "<div id=\"parent\">"
      "  <div id=\"scroller\"><div id=\"scrolled\"></div></div>"
      "</div>");
  document().view()->updateAllLifecyclePhases();

  EXPECT_TRUE(RuntimeEnabledFeatures::compositeOpaqueScrollersEnabled());
  Element* parent = document().getElementById("parent");
  Element* scroller = document().getElementById("scroller");
  PaintLayer* paintLayer =
      toLayoutBoxModelObject(scroller->layoutObject())->layer();
  ASSERT_TRUE(paintLayer);
  EXPECT_TRUE(paintLayer->needsCompositedScrolling());
  EXPECT_TRUE(paintLayer->graphicsLayerBacking());
  ASSERT_TRUE(paintLayer->graphicsLayerBackingForScrolling());
  EXPECT_TRUE(paintLayer->graphicsLayerBackingForScrolling()->contentsOpaque());

  // Change the parent to be partially translucent.
  parent->setAttribute(HTMLNames::styleAttr, "opacity: 0.5;");
  document().view()->updateAllLifecyclePhases();
  paintLayer = toLayoutBoxModelObject(scroller->layoutObject())->layer();
  ASSERT_TRUE(paintLayer);
  EXPECT_FALSE(paintLayer->needsCompositedScrolling());
  EXPECT_FALSE(paintLayer->graphicsLayerBacking());

  // Change the parent to be opaque again.
  parent->setAttribute(HTMLNames::styleAttr, "opacity: 1;");
  document().view()->updateAllLifecyclePhases();
  paintLayer = toLayoutBoxModelObject(scroller->layoutObject())->layer();
  ASSERT_TRUE(paintLayer);
  EXPECT_TRUE(paintLayer->needsCompositedScrolling());
  EXPECT_TRUE(paintLayer->graphicsLayerBacking());
  ASSERT_TRUE(paintLayer->graphicsLayerBackingForScrolling());
  EXPECT_TRUE(paintLayer->graphicsLayerBackingForScrolling()->contentsOpaque());

  // Make the scroller translucent.
  scroller->setAttribute(HTMLNames::styleAttr, "opacity: 0.5");
  document().view()->updateAllLifecyclePhases();
  paintLayer = toLayoutBoxModelObject(scroller->layoutObject())->layer();
  ASSERT_TRUE(paintLayer);
  EXPECT_FALSE(paintLayer->needsCompositedScrolling());
  EXPECT_FALSE(paintLayer->graphicsLayerBacking());
}

    ClipPathHelper(GraphicsContext* context, const PaintLayer& paintLayer, PaintLayerPaintingInfo& paintingInfo, LayoutRect& rootRelativeBounds, bool& rootRelativeBoundsComputed,
        const LayoutPoint& offsetFromRoot, PaintLayerFlags paintFlags)
        : m_resourceClipper(0), m_paintLayer(paintLayer), m_context(context)
    {
        const ComputedStyle& style = paintLayer.layoutObject()->styleRef();

        // 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.
        if (!paintLayer.layoutObject()->hasClipPath() || (paintLayer.needsCompositedScrolling() && !(paintFlags & PaintLayerPaintingChildClippingMaskPhase)))
            return;

        m_clipperState = SVGClipPainter::ClipperNotApplied;

        paintingInfo.ancestorHasClipPathClipping = true;

        ASSERT(style.clipPath());
        if (style.clipPath()->type() == ClipPathOperation::SHAPE) {
            ShapeClipPathOperation* clipPath = toShapeClipPathOperation(style.clipPath());
            if (clipPath->isValid()) {
                if (!rootRelativeBoundsComputed) {
                    rootRelativeBounds = paintLayer.physicalBoundingBoxIncludingReflectionAndStackingChildren(offsetFromRoot);
                    rootRelativeBoundsComputed = true;
                }
                m_clipPathRecorder.emplace(*context, *paintLayer.layoutObject(), clipPath->path(FloatRect(rootRelativeBounds)));
            }
        } else if (style.clipPath()->type() == ClipPathOperation::REFERENCE) {
            ReferenceClipPathOperation* referenceClipPathOperation = toReferenceClipPathOperation(style.clipPath());
            Document& document = paintLayer.layoutObject()->document();
            // FIXME: It doesn't work with forward or external SVG references (https://bugs.webkit.org/show_bug.cgi?id=90405)
            Element* element = document.getElementById(referenceClipPathOperation->fragment());
            if (isSVGClipPathElement(element) && element->layoutObject()) {
                if (!rootRelativeBoundsComputed) {
                    rootRelativeBounds = paintLayer.physicalBoundingBoxIncludingReflectionAndStackingChildren(offsetFromRoot);
                    rootRelativeBoundsComputed = true;
                }

                m_resourceClipper = toLayoutSVGResourceClipper(toLayoutSVGResourceContainer(element->layoutObject()));
                if (!SVGClipPainter(*m_resourceClipper).prepareEffect(*paintLayer.layoutObject(), FloatRect(rootRelativeBounds),
                    FloatRect(rootRelativeBounds), context, m_clipperState)) {
                    // No need to post-apply the clipper if this failed.
                    m_resourceClipper = 0;
                }
            }
        }
    }

void LayerClipRecorder::collectRoundedRectClips(PaintLayer& paintLayer, const PaintLayerPaintingInfo& localPaintingInfo, GraphicsContext& context, const LayoutPoint& fragmentOffset, PaintLayerFlags paintFlags,
        BorderRadiusClippingRule rule, Vector<FloatRoundedRect>& roundedRectClips)
{
    // If the clip rect has been tainted by a border radius, then we have to walk up our layer chain applying the clips from
    // any layers with overflow. The condition for being able to apply these clips is that the overflow object be in our
    // containing block chain so we check that also.
    for (PaintLayer* layer = rule == IncludeSelfForBorderRadius ? &paintLayer : paintLayer.parent(); layer; layer = layer->parent()) {
        // Composited scrolling layers handle border-radius clip in the compositor via a mask layer. We do not
        // want to apply a border-radius clip to the layer contents itself, because that would require re-rastering
        // every frame to update the clip. We only want to make sure that the mask layer is properly clipped so
        // that it can in turn clip the scrolled contents in the compositor.
        if (layer->needsCompositedScrolling() && !(paintFlags & PaintLayerPaintingChildClippingMaskPhase))
            break;

        if (layer->layoutObject()->hasOverflowClip() && layer->layoutObject()->style()->hasBorderRadius() && inContainingBlockChain(&paintLayer, layer)) {
            LayoutPoint delta(fragmentOffset);
            layer->convertToLayerCoords(localPaintingInfo.rootLayer, delta);
            roundedRectClips.append(layer->layoutObject()->style()->getRoundedInnerBorderFor(LayoutRect(delta, LayoutSize(layer->size()))));
        }

        if (layer == localPaintingInfo.rootLayer)
            break;
    }
}