C++ LayoutRect::intersects方法代码示例

bool LayoutImage::updateImageLoadingPriorities()
{
    if (!m_imageResource || !m_imageResource->cachedImage() || m_imageResource->cachedImage()->isLoaded())
        return false;

    LayoutRect viewBounds = viewRect();
    LayoutRect objectBounds = LayoutRect(absoluteContentBox());

    // The object bounds might be empty right now, so intersects will fail since it doesn't deal
    // with empty rects. Use LayoutRect::contains in that case.
    bool isVisible;
    if (!objectBounds.isEmpty())
        isVisible =  viewBounds.intersects(objectBounds);
    else
        isVisible = viewBounds.contains(objectBounds);

    ResourceLoadPriorityOptimizer::VisibilityStatus status = isVisible ?
        ResourceLoadPriorityOptimizer::Visible : ResourceLoadPriorityOptimizer::NotVisible;

    LayoutRect screenArea;
    if (!objectBounds.isEmpty()) {
        screenArea = viewBounds;
        screenArea.intersect(objectBounds);
    }

    ResourceLoadPriorityOptimizer::resourceLoadPriorityOptimizer()->notifyImageResourceVisibility(m_imageResource->cachedImage(), status, screenArea);

    return true;
}

void BlockPainter::paint(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
{
    Optional<SubtreeRecorder> subtreeRecorder;
    if (needsSubtreeRecorder(m_layoutBlock)) {
        subtreeRecorder.emplace(*paintInfo.context, m_layoutBlock, paintInfo.phase);
        if (subtreeRecorder->canUseCache())
            return;
    }

    PaintInfo localPaintInfo(paintInfo);

    LayoutPoint adjustedPaintOffset = paintOffset + m_layoutBlock.location();

    PaintPhase originalPhase = localPaintInfo.phase;

    // Check if we need to do anything at all.
    LayoutRect overflowBox = overflowRectForPaintRejection();
    m_layoutBlock.flipForWritingMode(overflowBox);
    overflowBox.moveBy(adjustedPaintOffset);
    if (!overflowBox.intersects(LayoutRect(localPaintInfo.rect)))
        return;

    // There are some cases where not all clipped visual overflow is accounted for.
    // FIXME: reduce the number of such cases.
    ContentsClipBehavior contentsClipBehavior = ForceContentsClip;
    if (m_layoutBlock.hasOverflowClip() && !m_layoutBlock.hasControlClip() && !(m_layoutBlock.shouldPaintSelectionGaps() && originalPhase == PaintPhaseForeground) && !hasCaret())
        contentsClipBehavior = SkipContentsClipIfPossible;

    if (localPaintInfo.phase == PaintPhaseOutline) {
        localPaintInfo.phase = PaintPhaseChildOutlines;
    } else if (localPaintInfo.phase == PaintPhaseChildBlockBackground) {
        localPaintInfo.phase = PaintPhaseBlockBackground;
        m_layoutBlock.paintObject(localPaintInfo, adjustedPaintOffset);
        localPaintInfo.phase = PaintPhaseChildBlockBackgrounds;
    }

    {
        BoxClipper boxClipper(m_layoutBlock, localPaintInfo, adjustedPaintOffset, contentsClipBehavior);
        m_layoutBlock.paintObject(localPaintInfo, adjustedPaintOffset);
    }

    if (originalPhase == PaintPhaseOutline) {
        localPaintInfo.phase = PaintPhaseSelfOutline;
        m_layoutBlock.paintObject(localPaintInfo, adjustedPaintOffset);
        localPaintInfo.phase = originalPhase;
    } else if (originalPhase == PaintPhaseChildBlockBackground) {
        localPaintInfo.phase = originalPhase;
    }

    // Our scrollbar widgets paint exactly when we tell them to, so that they work properly with
    // z-index. We paint after we painted the background/border, so that the scrollbars will
    // sit above the background/border.
    paintOverflowControlsIfNeeded(localPaintInfo, adjustedPaintOffset);
}

bool BlockPainter::intersectsPaintRect(const PaintInfo& paintInfo, const LayoutPoint& paintOffset) const
{
    LayoutRect overflowRect = m_layoutBlock.visualOverflowRect();
    if (m_layoutBlock.hasOverflowModel() && m_layoutBlock.usesCompositedScrolling()) {
        overflowRect.unite(m_layoutBlock.layoutOverflowRect());
        overflowRect.move(-m_layoutBlock.scrolledContentOffset());
    }
    m_layoutBlock.flipForWritingMode(overflowRect);
    overflowRect.moveBy(paintOffset + m_layoutBlock.location());
    return (overflowRect.intersects(LayoutRect(paintInfo.rect)));
}

void Page::addRelevantUnpaintedObject(RenderObject* object, const LayoutRect& objectPaintRect)
{
    if (!isCountingRelevantRepaintedObjects())
        return;

    // The objects are only relevant if they are being painted within the relevantViewRect().
    if (RenderView* view = object->view()) {
        if (!objectPaintRect.intersects(pixelSnappedIntRect(relevantViewRect(view))))
            return;
    }

    m_relevantUnpaintedRenderObjects.add(object);
    m_relevantUnpaintedRegion.unite(pixelSnappedIntRect(objectPaintRect));
}

static void deflateIfOverlapped(LayoutRect& a, LayoutRect& b)
{
    if (!a.intersects(b) || a.contains(b) || b.contains(a))
        return;

    LayoutUnit deflateFactor = -fudgeFactor();

    // Avoid negative width or height values.
    if ((a.width() + 2 * deflateFactor > 0) && (a.height() + 2 * deflateFactor > 0))
        a.inflate(deflateFactor);

    if ((b.width() + 2 * deflateFactor > 0) && (b.height() + 2 * deflateFactor > 0))
        b.inflate(deflateFactor);
}

bool canBeScrolledIntoView(FocusType type, const FocusCandidate& candidate)
{
    ASSERT(candidate.visibleNode && candidate.isOffscreen);
    LayoutRect candidateRect = candidate.rect;
    for (Node* parentNode = candidate.visibleNode->parentNode(); parentNode; parentNode = parentNode->parentNode()) {
        LayoutRect parentRect = nodeRectInAbsoluteCoordinates(parentNode);
        if (!candidateRect.intersects(parentRect)) {
            if (((type == FocusTypeLeft || type == FocusTypeRight) && parentNode->renderer()->style()->overflowX() == OHIDDEN)
                || ((type == FocusTypeUp || type == FocusTypeDown) && parentNode->renderer()->style()->overflowY() == OHIDDEN))
                return false;
        }
        if (parentNode == candidate.enclosingScrollableBox)
            return canScrollInDirection(parentNode, type);
    }
    return true;
}

// Checks if |node| is offscreen the visible area (viewport) of its container
// document. In case it is, one can scroll in direction or take any different
// desired action later on.
bool hasOffscreenRect(Node* node, FocusType type)
{
    // Get the FrameView in which |node| is (which means the current viewport if |node|
    // is not in an inner document), so we can check if its content rect is visible
    // before we actually move the focus to it.
    FrameView* frameView = node->document().view();
    if (!frameView)
        return true;

    ASSERT(!frameView->needsLayout());

    LayoutRect containerViewportRect = frameView->visibleContentRect();
    // We want to select a node if it is currently off screen, but will be
    // exposed after we scroll. Adjust the viewport to post-scrolling position.
    // If the container has overflow:hidden, we cannot scroll, so we do not pass direction
    // and we do not adjust for scrolling.
    switch (type) {
    case FocusTypeLeft:
        containerViewportRect.setX(containerViewportRect.x() - ScrollableArea::pixelsPerLineStep());
        containerViewportRect.setWidth(containerViewportRect.width() + ScrollableArea::pixelsPerLineStep());
        break;
    case FocusTypeRight:
        containerViewportRect.setWidth(containerViewportRect.width() + ScrollableArea::pixelsPerLineStep());
        break;
    case FocusTypeUp:
        containerViewportRect.setY(containerViewportRect.y() - ScrollableArea::pixelsPerLineStep());
        containerViewportRect.setHeight(containerViewportRect.height() + ScrollableArea::pixelsPerLineStep());
        break;
    case FocusTypeDown:
        containerViewportRect.setHeight(containerViewportRect.height() + ScrollableArea::pixelsPerLineStep());
        break;
    default:
        break;
    }

    RenderObject* render = node->renderer();
    if (!render)
        return true;

    LayoutRect rect(render->absoluteClippedOverflowRect());
    if (rect.isEmpty())
        return true;

    return !containerViewportRect.intersects(rect);
}

// Hit Testing
bool RenderRegion::nodeAtPoint(const HitTestRequest& request, HitTestResult& result, const LayoutPoint& pointInContainer, const LayoutPoint& accumulatedOffset, HitTestAction action)
{
    if (!isValid())
        return false;

    LayoutPoint adjustedLocation = accumulatedOffset + location();

    // Check our bounds next. For this purpose always assume that we can only be hit in the
    // foreground phase (which is true for replaced elements like images).
    LayoutRect boundsRect = borderBoxRectInRegion(result.region());
    boundsRect.moveBy(adjustedLocation);
    if (visibleToHitTesting() && action == HitTestForeground && boundsRect.intersects(result.rectForPoint(pointInContainer))) {
        // Check the contents of the RenderFlowThread.
        if (m_flowThread && m_flowThread->hitTestRegion(this, request, result, pointInContainer, LayoutPoint(adjustedLocation.x() + borderLeft() + paddingLeft(), adjustedLocation.y() + borderTop() + paddingTop())))
            return true;
        updateHitTestResult(result, pointInContainer - toLayoutSize(adjustedLocation));
        if (!result.addNodeToRectBasedTestResult(node(), pointInContainer, boundsRect))
            return true;
    }

    return false;
}

void Page::addRelevantRepaintedObject(RenderObject* object, const LayoutRect& objectPaintRect)
{
    if (!isCountingRelevantRepaintedObjects())
        return;

    // Objects inside sub-frames are not considered to be relevant.
    if (object->document()->frame() != mainFrame())
        return;

    RenderView* view = object->view();
    if (!view)
        return;

    LayoutRect relevantRect = relevantViewRect(view);

    // The objects are only relevant if they are being painted within the viewRect().
    if (!objectPaintRect.intersects(pixelSnappedIntRect(relevantRect)))
        return;

    IntRect snappedPaintRect = pixelSnappedIntRect(objectPaintRect);

    // If this object was previously counted as an unpainted object, remove it from that HashSet
    // and corresponding Region. FIXME: This doesn't do the right thing if the objects overlap.
    HashSet<RenderObject*>::iterator it = m_relevantUnpaintedRenderObjects.find(object);
    if (it != m_relevantUnpaintedRenderObjects.end()) {
        m_relevantUnpaintedRenderObjects.remove(it);
        m_relevantUnpaintedRegion.subtract(snappedPaintRect);
    }

    // Split the relevantRect into a top half and a bottom half. Making sure we have coverage in
    // both halves helps to prevent cases where we have a fully loaded menu bar or masthead with
    // no content beneath that.
    LayoutRect topRelevantRect = relevantRect;
    topRelevantRect.contract(LayoutSize(0, relevantRect.height() / 2));
    LayoutRect bottomRelevantRect = topRelevantRect;
    bottomRelevantRect.setY(relevantRect.height() / 2);

    // If the rect straddles both Regions, split it appropriately.
    if (topRelevantRect.intersects(snappedPaintRect) && bottomRelevantRect.intersects(snappedPaintRect)) {
        IntRect topIntersection = snappedPaintRect;
        topIntersection.intersect(pixelSnappedIntRect(topRelevantRect));
        m_topRelevantPaintedRegion.unite(topIntersection);

        IntRect bottomIntersection = snappedPaintRect;
        bottomIntersection.intersect(pixelSnappedIntRect(bottomRelevantRect));
        m_bottomRelevantPaintedRegion.unite(bottomIntersection);
    } else if (topRelevantRect.intersects(snappedPaintRect))
        m_topRelevantPaintedRegion.unite(snappedPaintRect);
    else
        m_bottomRelevantPaintedRegion.unite(snappedPaintRect);

    float topPaintedArea = m_topRelevantPaintedRegion.totalArea();
    float bottomPaintedArea = m_bottomRelevantPaintedRegion.totalArea();
    float viewArea = relevantRect.width() * relevantRect.height();

    float ratioThatIsPaintedOnTop = topPaintedArea / viewArea;
    float ratioThatIsPaintedOnBottom = bottomPaintedArea / viewArea;
    float ratioOfViewThatIsUnpainted = m_relevantUnpaintedRegion.totalArea() / viewArea;

    if (ratioThatIsPaintedOnTop > (gMinimumPaintedAreaRatio / 2) && ratioThatIsPaintedOnBottom > (gMinimumPaintedAreaRatio / 2)
        && ratioOfViewThatIsUnpainted < gMaximumUnpaintedAreaRatio) {
        m_isCountingRelevantRepaintedObjects = false;
        resetRelevantPaintedObjectCounter();
        if (Frame* frame = mainFrame())
            frame->loader()->didLayout(DidHitRelevantRepaintedObjectsAreaThreshold);
    }
}

bool CompositingReasonFinder::requiresCompositingForPosition(RenderObject* renderer, const RenderLayer* layer, RenderLayer::ViewportConstrainedNotCompositedReason* viewportConstrainedNotCompositedReason, bool* needToRecomputeCompositingRequirements) const
{
    // position:fixed elements that create their own stacking context (e.g. have an explicit z-index,
    // opacity, transform) can get their own composited layer. A stacking context is required otherwise
    // z-index and clipping will be broken.
    if (!renderer->isPositioned())
        return false;

    EPosition position = renderer->style()->position();
    bool isFixed = renderer->isOutOfFlowPositioned() && position == FixedPosition;
    // FIXME: The isStackingContainer check here is redundant. Fixed position elements are always stacking contexts.
    if (isFixed && !layer->stackingNode()->isStackingContainer())
        return false;

    bool isSticky = renderer->isInFlowPositioned() && position == StickyPosition;
    if (!isFixed && !isSticky)
        return false;

    // FIXME: acceleratedCompositingForFixedPositionEnabled should probably be renamed acceleratedCompositingForViewportConstrainedPositionEnabled().
    if (Settings* settings = m_renderView.document().settings()) {
        if (!settings->acceleratedCompositingForFixedPositionEnabled())
            return false;
    }

    if (isSticky)
        return isViewportConstrainedFixedOrStickyLayer(layer);

    RenderObject* container = renderer->container();
    // If the renderer is not hooked up yet then we have to wait until it is.
    if (!container) {
        *needToRecomputeCompositingRequirements = true;
        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.
    if (container != &m_renderView) {
        if (viewportConstrainedNotCompositedReason)
            *viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForNonViewContainer;
        return false;
    }

    // If the fixed-position element does not have any scrollable ancestor between it and
    // its container, then we do not need to spend compositor resources for it. Start by
    // assuming we can opt-out (i.e. no scrollable ancestor), and refine the answer below.
    bool hasScrollableAncestor = false;

    // The FrameView has the scrollbars associated with the top level viewport, so we have to
    // check the FrameView in addition to the hierarchy of ancestors.
    FrameView* frameView = m_renderView.frameView();
    if (frameView && frameView->isScrollable())
        hasScrollableAncestor = true;

    RenderLayer* ancestor = layer->parent();
    while (ancestor && !hasScrollableAncestor) {
        if (frameView->containsScrollableArea(ancestor->scrollableArea()))
            hasScrollableAncestor = true;
        if (ancestor->renderer() == &m_renderView)
            break;
        ancestor = ancestor->parent();
    }

    if (!hasScrollableAncestor) {
        if (viewportConstrainedNotCompositedReason)
            *viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForUnscrollableAncestors;
        return false;
    }

    // Subsequent tests depend on layout. If we can't tell now, just keep things the way they are until layout is done.
    if (m_renderView.document().lifecycle().state() < DocumentLifecycle::LayoutClean) {
        *needToRecomputeCompositingRequirements = true;
        return layer->hasCompositedLayerMapping();
    }

    bool paintsContent = layer->isVisuallyNonEmpty() || layer->hasVisibleDescendant();
    if (!paintsContent) {
        if (viewportConstrainedNotCompositedReason)
            *viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForNoVisibleContent;
        return false;
    }

    // Fixed position elements that are invisible in the current view don't get their own layer.
    if (FrameView* frameView = m_renderView.frameView()) {
        LayoutRect viewBounds = frameView->viewportConstrainedVisibleContentRect();
        LayoutRect layerBounds = layer->calculateLayerBounds(layer->compositor()->rootRenderLayer(), 0,
            RenderLayer::DefaultCalculateLayerBoundsFlags
            | RenderLayer::ExcludeHiddenDescendants
            | RenderLayer::DontConstrainForMask
            | RenderLayer::IncludeCompositedDescendants
            | RenderLayer::PretendLayerHasOwnBacking);
        if (!viewBounds.intersects(enclosingIntRect(layerBounds))) {
            if (viewportConstrainedNotCompositedReason) {
                *viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForBoundsOutOfView;
                *needToRecomputeCompositingRequirements = true;
            }
            return false;
        }
    }

    return true;
//.........这里部分代码省略.........

bool CompositingReasonFinder::requiresCompositingForPositionFixed(RenderObject* renderer, const RenderLayer* layer, RenderLayer::ViewportConstrainedNotCompositedReason* viewportConstrainedNotCompositedReason, bool* needToRecomputeCompositingRequirements) const
{
    if (!(m_compositingTriggers & ViewportConstrainedPositionedTrigger))
        return false;

    if (renderer->style()->position() != FixedPosition)
        return false;

    RenderObject* container = renderer->container();
    // If the renderer is not hooked up yet then we have to wait until it is.
    if (!container) {
        ASSERT(m_renderView.document().lifecycle().state() < DocumentLifecycle::InCompositingUpdate);
        // FIXME: Remove this and ASSERT(container) once we get rid of the incremental
        // allocateOrClearCompositedLayerMapping compositing update. This happens when
        // adding the renderer to the tree because we setStyle before addChild in
        // createRendererForElementIfNeeded.
        *needToRecomputeCompositingRequirements = true;
        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.
    if (container != &m_renderView) {
        if (viewportConstrainedNotCompositedReason)
            *viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForNonViewContainer;
        return false;
    }

    // If the fixed-position element does not have any scrollable ancestor between it and
    // its container, then we do not need to spend compositor resources for it. Start by
    // assuming we can opt-out (i.e. no scrollable ancestor), and refine the answer below.
    bool hasScrollableAncestor = false;

    // The FrameView has the scrollbars associated with the top level viewport, so we have to
    // check the FrameView in addition to the hierarchy of ancestors.
    FrameView* frameView = m_renderView.frameView();
    if (frameView && frameView->isScrollable())
        hasScrollableAncestor = true;

    RenderLayer* ancestor = layer->parent();
    while (ancestor && !hasScrollableAncestor) {
        if (ancestor->scrollsOverflow())
            hasScrollableAncestor = true;
        if (ancestor->renderer() == &m_renderView)
            break;
        ancestor = ancestor->parent();
    }

    if (!hasScrollableAncestor) {
        if (viewportConstrainedNotCompositedReason)
            *viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForUnscrollableAncestors;
        return false;
    }

    // Subsequent tests depend on layout. If we can't tell now, just keep things the way they are until layout is done.
    // FIXME: Get rid of this codepath once we get rid of the incremental compositing update in RenderLayer::styleChanged.
    if (m_renderView.document().lifecycle().state() < DocumentLifecycle::LayoutClean) {
        *needToRecomputeCompositingRequirements = true;
        return layer->hasCompositedLayerMapping();
    }

    bool paintsContent = layer->isVisuallyNonEmpty() || layer->hasVisibleDescendant();
    if (!paintsContent) {
        if (viewportConstrainedNotCompositedReason)
            *viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForNoVisibleContent;
        return false;
    }

    // Fixed position elements that are invisible in the current view don't get their own layer.
    if (FrameView* frameView = m_renderView.frameView()) {
        ASSERT(m_renderView.document().lifecycle().state() == DocumentLifecycle::InCompositingUpdate);
        LayoutRect viewBounds = frameView->viewportConstrainedVisibleContentRect();
        LayoutRect layerBounds = layer->boundingBoxForCompositing(layer->compositor()->rootRenderLayer(), RenderLayer::ApplyBoundsChickenEggHacks);
        if (!viewBounds.intersects(enclosingIntRect(layerBounds))) {
            if (viewportConstrainedNotCompositedReason)
                *viewportConstrainedNotCompositedReason = RenderLayer::NotCompositedForBoundsOutOfView;
            return false;
        }
    }

    return true;
}