renderlayer.cpp

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

    // Schedule the scroll DOM event.
    if (view) {
        if (FrameView* frameView = view->frameView())
            frameView->scheduleEvent(Event::create(eventNames().scrollEvent, false, false), renderer()->node());
    }
}

void RenderLayer::scrollRectToVisible(const IntRect &rect, bool scrollToAnchor, const ScrollAlignment& alignX, const ScrollAlignment& alignY)
{
    RenderLayer* parentLayer = 0;
    IntRect newRect = rect;
    int xOffset = 0, yOffset = 0;

    // We may end up propagating a scroll event. It is important that we suspend events until 
    // the end of the function since they could delete the layer or the layer's renderer().
    FrameView* frameView = renderer()->document()->view();
    if (frameView)
        frameView->pauseScheduledEvents();

    bool restrictedByLineClamp = false;
    if (renderer()->parent()) {
        parentLayer = renderer()->parent()->enclosingLayer();
        restrictedByLineClamp = renderer()->parent()->style()->lineClamp() >= 0;
    }

    if (renderer()->hasOverflowClip() && !restrictedByLineClamp) {
        // Don't scroll to reveal an overflow layer that is restricted by the -webkit-line-clamp property.
        // This will prevent us from revealing text hidden by the slider in Safari RSS.
        RenderBox* box = renderBox();
        ASSERT(box);
        FloatPoint absPos = box->localToAbsolute();
        absPos.move(box->borderLeft(), box->borderTop());

        IntRect layerBounds = IntRect(absPos.x() + scrollXOffset(), absPos.y() + scrollYOffset(), box->clientWidth(), box->clientHeight());
        IntRect exposeRect = IntRect(rect.x() + scrollXOffset(), rect.y() + scrollYOffset(), rect.width(), rect.height());
        IntRect r = getRectToExpose(layerBounds, exposeRect, alignX, alignY);
        
        xOffset = r.x() - absPos.x();
        yOffset = r.y() - absPos.y();
        // Adjust offsets if they're outside of the allowable range.
        xOffset = max(0, min(scrollWidth() - layerBounds.width(), xOffset));
        yOffset = max(0, min(scrollHeight() - layerBounds.height(), yOffset));
        
        if (xOffset != scrollXOffset() || yOffset != scrollYOffset()) {
            int diffX = scrollXOffset();
            int diffY = scrollYOffset();
            scrollToOffset(xOffset, yOffset);
            diffX = scrollXOffset() - diffX;
            diffY = scrollYOffset() - diffY;
            newRect.setX(rect.x() - diffX);
            newRect.setY(rect.y() - diffY);
        }
    } else if (!parentLayer && renderer()->isBox() && renderBox()->canBeProgramaticallyScrolled(scrollToAnchor)) {
        if (frameView) {
            if (renderer()->document() && renderer()->document()->ownerElement() && renderer()->document()->ownerElement()->renderer()) {
                IntRect viewRect = frameView->visibleContentRect();
                IntRect r = getRectToExpose(viewRect, rect, alignX, alignY);
                
                xOffset = r.x();
                yOffset = r.y();
                // Adjust offsets if they're outside of the allowable range.
                xOffset = max(0, min(frameView->contentsWidth(), xOffset));
                yOffset = max(0, min(frameView->contentsHeight(), yOffset));

                frameView->setScrollPosition(IntPoint(xOffset, yOffset));
                parentLayer = renderer()->document()->ownerElement()->renderer()->enclosingLayer();
                newRect.setX(rect.x() - frameView->scrollX() + frameView->x());
                newRect.setY(rect.y() - frameView->scrollY() + frameView->y());
            } else {
                IntRect viewRect = frameView->visibleContentRect(true);
                IntRect r = getRectToExpose(viewRect, rect, alignX, alignY);
                
                // If this is the outermost view that RenderLayer needs to scroll, then we should scroll the view recursively
                // Other apps, like Mail, rely on this feature.
                frameView->scrollRectIntoViewRecursively(r);
            }
        }
    }
    
    if (parentLayer)
        parentLayer->scrollRectToVisible(newRect, scrollToAnchor, alignX, alignY);

    if (frameView)
        frameView->resumeScheduledEvents();
}

IntRect RenderLayer::getRectToExpose(const IntRect &visibleRect, const IntRect &exposeRect, const ScrollAlignment& alignX, const ScrollAlignment& alignY)
{
    // Determine the appropriate X behavior.
    ScrollBehavior scrollX;
    IntRect exposeRectX(exposeRect.x(), visibleRect.y(), exposeRect.width(), visibleRect.height());
    int intersectWidth = intersection(visibleRect, exposeRectX).width();
    if (intersectWidth == exposeRect.width() || intersectWidth >= MIN_INTERSECT_FOR_REVEAL)
        // If the rectangle is fully visible, use the specified visible behavior.
        // If the rectangle is partially visible, but over a certain threshold,
        // then treat it as fully visible to avoid unnecessary horizontal scrolling
        scrollX = ScrollAlignment::getVisibleBehavior(alignX);
    else if (intersectWidth == visibleRect.width()) {
        // If the rect is bigger than the visible area, don't bother trying to center. Other alignments will work.
        scrollX = ScrollAlignment::getVisibleBehavior(alignX);
        if (scrollX == alignCenter)
            scrollX = noScroll;
    } else if (intersectWidth > 0)
        // If the rectangle is partially visible, but not above the minimum threshold, use the specified partial behavior
        scrollX = ScrollAlignment::getPartialBehavior(alignX);
    else
        scrollX = ScrollAlignment::getHiddenBehavior(alignX);
    // If we're trying to align to the closest edge, and the exposeRect is further right
    // than the visibleRect, and not bigger than the visible area, then align with the right.
    if (scrollX == alignToClosestEdge && exposeRect.right() > visibleRect.right() && exposeRect.width() < visibleRect.width())
        scrollX = alignRight;

    // Given the X behavior, compute the X coordinate.
    int x;
    if (scrollX == noScroll) 
        x = visibleRect.x();
    else if (scrollX == alignRight)
        x = exposeRect.right() - visibleRect.width();
    else if (scrollX == alignCenter)
        x = exposeRect.x() + (exposeRect.width() - visibleRect.width()) / 2;
    else
        x = exposeRect.x();

    // Determine the appropriate Y behavior.
    ScrollBehavior scrollY;
    IntRect exposeRectY(visibleRect.x(), exposeRect.y(), visibleRect.width(), exposeRect.height());
    int intersectHeight = intersection(visibleRect, exposeRectY).height();
    if (intersectHeight == exposeRect.height())
        // If the rectangle is fully visible, use the specified visible behavior.
        scrollY = ScrollAlignment::getVisibleBehavior(alignY);
    else if (intersectHeight == visibleRect.height()) {
        // If the rect is bigger than the visible area, don't bother trying to center. Other alignments will work.
        scrollY = ScrollAlignment::getVisibleBehavior(alignY);
        if (scrollY == alignCenter)
            scrollY = noScroll;
    } else if (intersectHeight > 0)
        // If the rectangle is partially visible, use the specified partial behavior
        scrollY = ScrollAlignment::getPartialBehavior(alignY);
    else
        scrollY = ScrollAlignment::getHiddenBehavior(alignY);
    // If we're trying to align to the closest edge, and the exposeRect is further down
    // than the visibleRect, and not bigger than the visible area, then align with the bottom.
    if (scrollY == alignToClosestEdge && exposeRect.bottom() > visibleRect.bottom() && exposeRect.height() < visibleRect.height())
        scrollY = alignBottom;

    // Given the Y behavior, compute the Y coordinate.
    int y;
    if (scrollY == noScroll) 
        y = visibleRect.y();
    else if (scrollY == alignBottom)
        y = exposeRect.bottom() - visibleRect.height();
    else if (scrollY == alignCenter)
        y = exposeRect.y() + (exposeRect.height() - visibleRect.height()) / 2;
    else
        y = exposeRect.y();

    return IntRect(IntPoint(x, y), visibleRect.size());
}

void RenderLayer::autoscroll()
{
    Frame* frame = renderer()->document()->frame();
    if (!frame)
        return;

    FrameView* frameView = frame->view();
    if (!frameView)
        return;

    frame->eventHandler()->updateSelectionForMouseDrag();

    IntPoint currentDocumentPosition = frameView->windowToContents(frame->eventHandler()->currentMousePosition());
    scrollRectToVisible(IntRect(currentDocumentPosition, IntSize(1, 1)), false, ScrollAlignment::alignToEdgeIfNeeded, ScrollAlignment::alignToEdgeIfNeeded);
}

void RenderLayer::resize(const PlatformMouseEvent& evt, const IntSize& oldOffset)
{
    // FIXME: This should be possible on generated content but is not right now.
    if (!inResizeMode() || !renderer()->hasOverflowClip() || !renderer()->node())
        return;

    // Set the width and height of the shadow ancestor node if there is one.
    // This is necessary for textarea elements since the resizable layer is in the shadow content.
    Element* element = static_cast<Element*>(renderer()->node()->shadowAncestorNode());
    RenderBox* renderer = toRenderBox(element->renderer());

    EResize resize = renderer->style()->resize();
    if (resize == RESIZE_NONE)
        return;

    Document* document = element->document();
    if (!document->frame()->eventHandler()->mousePressed())
        return;

    float zoomFactor = renderer->style()->effectiveZoom();

    IntSize newOffset = offsetFromResizeCorner(document->view()->windowToContents(evt.pos()));
    newOffset.setWidth(newOffset.width() / zoomFactor);
    newOffset.setHeight(newOffset.height() / zoomFactor);
    
    IntSize currentSize = IntSize(renderer->width() / zoomFactor, renderer->height() / zoomFactor);
    IntSize minimumSize = element->minimumSizeForResizing().shrunkTo(currentSize);
    element->setMinimumSizeForResizing(minimumSize);
    
    IntSize adjustedOldOffset = IntSize(oldOffset.width() / zoomFactor, oldOffset.height() / zoomFactor);
    
    IntSize difference = (currentSize + newOffset - adjustedOldOffset).expandedTo(minimumSize) - currentSize;

    CSSStyleDeclaration* style = element->style();
    bool isBoxSizingBorder = renderer->style()->boxSizing() == BORDER_BOX;

    ExceptionCode ec;

    if (difference.width()) {
        if (element && element->isFormControlElement()) {
            // Make implicit margins from the theme explicit (see <http://bugs.webkit.org/show_bug.cgi?id=9547>).
            style->setProperty(CSSPropertyMarginLeft, String::number(renderer->marginLeft() / zoomFactor) + "px", false, ec);
            style->setProperty(CSSPropertyMarginRight, String::number(renderer->marginRight() / zoomFactor) + "px", false, ec);
        }
        int baseWidth = renderer->width() - (isBoxSizingBorder ? 0
            : renderer->borderLeft() + renderer->paddingLeft() + renderer->borderRight() + renderer->paddingRight());
        baseWidth = baseWidth / zoomFactor;
        style->setProperty(CSSPropertyWidth, String::number(baseWidth + difference.width()) + "px", false, ec);
    }

    if (difference.height()) {
        if (element && element->isFormControlElement()) {
            // Make implicit margins from the theme explicit (see <http://bugs.webkit.org/show_bug.cgi?id=9547>).
            style->setProperty(CSSPropertyMarginTop, String::number(renderer->marginTop() / zoomFactor) + "px", false, ec);
            style->setProperty(CSSPropertyMarginBottom, String::number(renderer->marginBottom() / zoomFactor) + "px", false, ec);
        }
        int baseHeight = renderer->height() - (isBoxSizingBorder ? 0
            : renderer->borderTop() + renderer->paddingTop() + renderer->borderBottom() + renderer->paddingBottom());
        baseHeight = baseHeight / zoomFactor;
        style->setProperty(CSSPropertyHeight, String::number(baseHeight + difference.height()) + "px", false, ec);
    }

    document->updateLayout();

    // FIXME (Radar 4118564): We should also autoscroll the window as necessary to keep the point under the cursor in view.
}

void RenderLayer::valueChanged(Scrollbar*)
{
    // Update scroll position from scrollbars.

    bool needUpdate = false;
    int newX = scrollXOffset();
    int newY = m_scrollY;
    
    if (m_hBar) {
        newX = m_hBar->value();
        if (newX != scrollXOffset())
           needUpdate = true;
    }

    if (m_vBar) {
        newY = m_vBar->value();
        if (newY != m_scrollY)
           needUpdate = true;
    }

    if (needUpdate)
        scrollToOffset(newX, newY, false);
}

bool RenderLayer::isActive() const
{
    Page* page = renderer()->document()->frame()->page();
    return page && page->focusController()->isActive();
}


static IntRect cornerRect(const RenderLayer* layer, const IntRect& bounds)
{
    int horizontalThickness;
    int verticalThickness;
    if (!layer->verticalScrollbar() && !layer->horizontalScrollbar()) {
        // FIXME: This isn't right.  We need to know the thickness of custom scrollbars
        // even when they don't exist in order to set the resizer square size properly.
        horizontalThickness = ScrollbarTheme::nativeTheme()->scrollbarThickness();
        verticalThickness = horizontalThickness;
    } else if (layer->verticalScrollbar() && !layer->horizontalScrollbar()) {
        horizontalThickness = layer->verticalScrollbar()->width();
        verticalThickness = horizontalThickness;
    } else if (layer->horizontalScrollbar() && !layer->verticalScrollbar()) {
        verticalThickness = layer->horizontalScrollbar()->height();
        horizontalThickness = verticalThickness;
    } else {
        horizontalThickness = layer->verticalScrollbar()->width();
        verticalThickness = layer->horizontalScrollbar()->height();
    }
    return IntRect(bounds.right() - horizontalThickness - layer->renderer()->style()->borderRightWidth(), 
                   bounds.bottom() - verticalThickness - layer->renderer()->style()->borderBottomWidth(),
                   horizontalThickness, verticalThickness);
}

static IntRect scrollCornerRect(const RenderLayer* layer, const IntRect& bounds)
{
    // We have a scrollbar corner when a scrollbar is visible and not filling the entire length of the box.
    // This happens when:
    // (a) A resizer is present and at least one scrollbar is present
    // (b) Both scrollbars are present.
    bool hasHorizontalBar = layer->horizontalScrollbar();
    bool hasVerticalBar = layer->verticalScrollbar();
    bool hasResizer = layer->renderer()->style()->resize() != RESIZE_NONE;
    if ((hasHorizontalBar && hasVerticalBar) || (hasResizer && (hasHorizontalBar || hasVerticalBar)))
        return cornerRect(layer, bounds);
    return IntRect();
}

static IntRect resizerCornerRect(const RenderLayer* layer, const IntRect& bounds)
{
    ASSERT(layer->renderer()->isBox());
    if (layer->renderer()->style()->resize() == RESIZE_NONE)
        return IntRect();
    return cornerRect(layer, bounds);
}

bool RenderLayer::scrollbarCornerPresent() const
{
    ASSERT(renderer()->isBox());
    return !scrollCornerRect(this, renderBox()->borderBoxRect()).isEmpty();
}

void RenderLayer::invalidateScrollbarRect(Scrollbar* scrollbar, const IntRect& rect)
{
    IntRect scrollRect = rect;
    RenderBox* box = renderBox();
    ASSERT(box);
    if (scrollbar == m_vBar.get())
        scrollRect.move(box->width() - box->borderRight() - box->width(), box->borderTop());
    else
        scrollRect.move(box->borderLeft(), box->height() - box->borderBottom() - scrollbar->height());
    renderer()->repaintRectangle(scrollRect);
}

PassRefPtr<Scrollbar> RenderLayer::createScrollbar(ScrollbarOrientation orientation)
{
    RefPtr<Scrollbar> widget;
    RenderObject* actualRenderer = renderer()->node() ? renderer()->node()->shadowAncestorNode()->renderer() : renderer();
    bool hasCustomScrollbarStyle = actualRenderer->isBox() && actualRenderer->style()->hasPseudoStyle(SCROLLBAR);
    if (hasCustomScrollbarStyle)
        widget = RenderScrollbar::createCustomScrollbar(this, orientation, toRenderBox(actualRenderer));
    else
        widget = Scrollbar::createNativeScrollbar(this, orientation, RegularScrollbar);
    renderer()->document()->view()->addChild(widget.get());        
    return widget.release();
}

void RenderLayer::destroyScrollbar(ScrollbarOrientation orientation)
{
    RefPtr<Scrollbar>& scrollbar = orientation == HorizontalScrollbar ? m_hBar : m_vBar;
    if (scrollbar) {
        scrollbar->removeFromParent();
        scrollbar->setClient(0);