C++ ScrollableArea::scrollPosition方法代码示例

void AccessibilityObject::scrollToGlobalPoint(const IntPoint& globalPoint) const
{
    // Search up the parent chain and create a vector of all scrollable parent objects
    // and ending with this object itself.
    Vector<const AccessibilityObject*> objects;
    AccessibilityObject* parentObject;
    for (parentObject = this->parentObject(); parentObject; parentObject = parentObject->parentObject()) {
        if (parentObject->getScrollableAreaIfScrollable())
            objects.prepend(parentObject);
    }
    objects.append(this);

    // Start with the outermost scrollable (the main window) and try to scroll the
    // next innermost object to the given point.
    int offsetX = 0, offsetY = 0;
    IntPoint point = globalPoint;
    size_t levels = objects.size() - 1;
    for (size_t i = 0; i < levels; i++) {
        const AccessibilityObject* outer = objects[i];
        const AccessibilityObject* inner = objects[i + 1];

        ScrollableArea* scrollableArea = outer->getScrollableAreaIfScrollable();

        LayoutRect innerRect = inner->isAccessibilityScrollView() ? inner->parentObject()->elementRect() : inner->elementRect();
        LayoutRect objectRect = innerRect;
        IntPoint scrollPosition = scrollableArea->scrollPosition();

        // Convert the object rect into local coordinates.
        objectRect.move(offsetX, offsetY);
        if (!outer->isAccessibilityScrollView())
            objectRect.move(scrollPosition.x(), scrollPosition.y());

        int desiredX = computeBestScrollOffset(
            0,
            objectRect.x(), objectRect.maxX(),
            objectRect.x(), objectRect.maxX(),
            point.x(), point.x());
        int desiredY = computeBestScrollOffset(
            0,
            objectRect.y(), objectRect.maxY(),
            objectRect.y(), objectRect.maxY(),
            point.y(), point.y());
        outer->scrollTo(IntPoint(desiredX, desiredY));

        if (outer->isAccessibilityScrollView() && !inner->isAccessibilityScrollView()) {
            // If outer object we just scrolled is a scroll view (main window or iframe) but the
            // inner object is not, keep track of the coordinate transformation to apply to
            // future nested calculations.
            scrollPosition = scrollableArea->scrollPosition();
            offsetX -= (scrollPosition.x() + point.x());
            offsetY -= (scrollPosition.y() + point.y());
            point.move(scrollPosition.x() - innerRect.x(),
                       scrollPosition.y() - innerRect.y());
        } else if (inner->isAccessibilityScrollView()) {
            // Otherwise, if the inner object is a scroll view, reset the coordinate transformation.
            offsetX = 0;
            offsetY = 0;
        }
    }
}

IntPoint AXObject::scrollOffset() const
{
    ScrollableArea* area = getScrollableAreaIfScrollable();
    if (!area)
        return IntPoint();

    return IntPoint(area->scrollPosition().x(), area->scrollPosition().y());
}

void AccessibilityObject::scrollToMakeVisibleWithSubFocus(const IntRect& subfocus) const
{
    // Search up the parent chain until we find the first one that's scrollable.
    AccessibilityObject* scrollParent = parentObject();
    ScrollableArea* scrollableArea;
    for (scrollableArea = 0;
         scrollParent && !(scrollableArea = scrollParent->getScrollableAreaIfScrollable());
         scrollParent = scrollParent->parentObject()) { }
    if (!scrollableArea)
        return;

    LayoutRect objectRect = elementRect();
    IntPoint scrollPosition = scrollableArea->scrollPosition();
    IntRect scrollVisibleRect = scrollableArea->visibleContentRect();

    int desiredX = computeBestScrollOffset(
        scrollPosition.x(),
        objectRect.x() + subfocus.x(), objectRect.x() + subfocus.maxX(),
        objectRect.x(), objectRect.maxX(),
        0, scrollVisibleRect.width());
    int desiredY = computeBestScrollOffset(
        scrollPosition.y(),
        objectRect.y() + subfocus.y(), objectRect.y() + subfocus.maxY(),
        objectRect.y(), objectRect.maxY(),
        0, scrollVisibleRect.height());

    scrollParent->scrollTo(IntPoint(desiredX, desiredY));

    // Recursively make sure the scroll parent itself is visible.
    if (scrollParent->parentObject())
        scrollParent->scrollToMakeVisible();
}

InRegionScrollableArea::InRegionScrollableArea(WebPagePrivate* webPage, RenderLayer* layer)
    : m_webPage(webPage)
    , m_layer(layer)
{
    ASSERT(webPage);
    ASSERT(layer);
    m_isNull = false;

    // FIXME: Add an ASSERT here as the 'layer' must be scrollable.

    RenderObject* layerRenderer = layer->renderer();
    ASSERT(layerRenderer);

    if (layerRenderer->isRenderView()) { // #document case

        FrameView* view = toRenderView(layerRenderer)->frameView();
        ASSERT(view);

        Frame* frame = view->frame();
        ASSERT_UNUSED(frame, frame);

        m_scrollPosition = m_webPage->mapToTransformed(view->scrollPosition());
        m_contentsSize = m_webPage->mapToTransformed(view->contentsSize());
        m_viewportSize = m_webPage->mapToTransformed(view->visibleContentRect(false /*includeScrollbars*/)).size();

        m_visibleWindowRect = m_webPage->mapToTransformed(m_webPage->getRecursiveVisibleWindowRect(view));
        IntRect transformedWindowRect = IntRect(IntPoint::zero(), m_webPage->transformedViewportSize());
        m_visibleWindowRect.intersect(transformedWindowRect);

        m_scrollsHorizontally = view->contentsWidth() > view->visibleWidth();
        m_scrollsVertically = view->contentsHeight() > view->visibleHeight();

        m_overscrollLimitFactor = 0.0; // FIXME eventually support overscroll
    } else { // RenderBox-based elements case (scrollable boxes (div's, p's, textarea's, etc)).

        RenderBox* box = m_layer->renderBox();
        ASSERT(box);
        ASSERT(box->canBeScrolledAndHasScrollableArea());

        ScrollableArea* scrollableArea = static_cast<ScrollableArea*>(m_layer);
        m_scrollPosition = m_webPage->mapToTransformed(scrollableArea->scrollPosition());
        m_contentsSize = m_webPage->mapToTransformed(scrollableArea->contentsSize());
        m_viewportSize = m_webPage->mapToTransformed(scrollableArea->visibleContentRect(false /*includeScrollbars*/)).size();

        m_visibleWindowRect = m_layer->renderer()->absoluteClippedOverflowRect();
        m_visibleWindowRect = m_layer->renderer()->frame()->view()->contentsToWindow(m_visibleWindowRect);
        IntRect visibleFrameWindowRect = m_webPage->getRecursiveVisibleWindowRect(m_layer->renderer()->frame()->view());
        m_visibleWindowRect.intersect(visibleFrameWindowRect);
        m_visibleWindowRect = m_webPage->mapToTransformed(m_visibleWindowRect);
        IntRect transformedWindowRect = IntRect(IntPoint::zero(), m_webPage->transformedViewportSize());
        m_visibleWindowRect.intersect(transformedWindowRect);

        m_scrollsHorizontally = box->scrollWidth() != box->clientWidth() && box->scrollsOverflowX();
        m_scrollsVertically = box->scrollHeight() != box->clientHeight() && box->scrollsOverflowY();

        m_overscrollLimitFactor = 0.0; // FIXME eventually support overscroll
    }
}

void AXObject::scrollToMakeVisibleWithSubFocus(const IntRect& subfocus) const
{
    // Search up the parent chain until we find the first one that's scrollable.
    AXObject* scrollParent = parentObject();
    ScrollableArea* scrollableArea = 0;
    while (scrollParent) {
        scrollableArea = scrollParent->getScrollableAreaIfScrollable();
        if (scrollableArea && !scrollParent->isAXScrollView())
            break;
        scrollParent = scrollParent->parentObject();
    }
    if (!scrollParent || !scrollableArea)
        return;

    IntRect objectRect = pixelSnappedIntRect(elementRect());
    IntPoint scrollPosition = scrollableArea->scrollPosition();
    IntRect scrollVisibleRect = scrollableArea->visibleContentRect();

    // Convert the object rect into local coordinates.
    if (!scrollParent->isWebArea()) {
        objectRect.moveBy(scrollPosition);
        objectRect.moveBy(-pixelSnappedIntRect(scrollParent->elementRect()).location());
    }

    int desiredX = computeBestScrollOffset(
        scrollPosition.x(),
        objectRect.x() + subfocus.x(), objectRect.x() + subfocus.maxX(),
        objectRect.x(), objectRect.maxX(),
        0, scrollVisibleRect.width());
    int desiredY = computeBestScrollOffset(
        scrollPosition.y(),
        objectRect.y() + subfocus.y(), objectRect.y() + subfocus.maxY(),
        objectRect.y(), objectRect.maxY(),
        0, scrollVisibleRect.height());

    scrollParent->setScrollOffset(IntPoint(desiredX, desiredY));

    // Convert the subfocus into the coordinates of the scroll parent.
    IntRect newSubfocus = subfocus;
    IntRect newElementRect = pixelSnappedIntRect(elementRect());
    IntRect scrollParentRect = pixelSnappedIntRect(scrollParent->elementRect());
    newSubfocus.move(newElementRect.x(), newElementRect.y());
    newSubfocus.move(-scrollParentRect.x(), -scrollParentRect.y());

    // Recursively make sure the scroll parent itself is visible.
    if (scrollParent->parentObject())
        scrollParent->scrollToMakeVisibleWithSubFocus(newSubfocus);
}

InRegionScrollableArea::InRegionScrollableArea(WebPagePrivate* webPage, RenderLayer* layer)
    : m_webPage(webPage)
    , m_layer(layer)
    , m_document(0)
    , m_hasWindowVisibleRectCalculated(false)
{
    ASSERT(webPage);
    ASSERT(layer);
    m_isNull = false;

    // Add a pointer to the enclosing document as the pointer to layer or node along the way may become invalid.
    if (m_layer->enclosingElement())
        m_document = m_layer->enclosingElement()->document();

    // FIXME: Add an ASSERT here as the 'layer' must be scrollable.

    RenderObject* layerRenderer = layer->renderer();
    ASSERT(layerRenderer);

    if (layerRenderer->isRenderView()) { // #document case

        RenderView* renderView = toRenderView(layerRenderer);
        ASSERT(renderView);

        FrameView* view = toRenderView(layerRenderer)->frameView();
        ASSERT(view);

        Frame* frame = view->frame();
        ASSERT_UNUSED(frame, frame);

        const Platform::ViewportAccessor* viewportAccessor = m_webPage->m_webkitThreadViewportAccessor;
        m_scrollPosition = viewportAccessor->roundToPixelFromDocumentContents(WebCore::FloatPoint(view->scrollPosition()));
        m_contentsSize = viewportAccessor->roundToPixelFromDocumentContents(Platform::FloatRect(Platform::FloatPoint::zero(), WebCore::FloatSize(view->contentsSize()))).size();
        m_viewportSize = viewportAccessor->roundToPixelFromDocumentContents(WebCore::FloatRect(view->visibleContentRect(ScrollableArea::ExcludeScrollbars))).size();
        m_documentViewportRect = view->frameRect();

        m_scrollsHorizontally = view->contentsWidth() > view->visibleWidth();
        m_scrollsVertically = view->contentsHeight() > view->visibleHeight();

        m_supportsCompositedScrolling = true;

        m_scrollTarget = InnerFrame;

        ASSERT(!m_cachedNonCompositedScrollableNode);

        m_camouflagedCompositedScrollableLayer = reinterpret_cast<unsigned>(renderView->compositor()->scrollLayer()->platformLayer());
        m_cachedCompositedScrollableLayer = renderView->compositor()->scrollLayer()->platformLayer();

    } else { // RenderBox-based elements case (scrollable boxes (div's, p's, textarea's, etc)).

        RenderBox* box = m_layer->renderBox();
        ASSERT(box);
        ASSERT(InRegionScrollerPrivate::canScrollRenderBox(box));

        const Platform::ViewportAccessor* viewportAccessor = m_webPage->m_webkitThreadViewportAccessor;
        ScrollableArea* scrollableArea = static_cast<ScrollableArea*>(m_layer);

        m_scrollPosition = viewportAccessor->roundToPixelFromDocumentContents(WebCore::FloatPoint(scrollableArea->scrollPosition()));
        m_contentsSize = viewportAccessor->roundToPixelFromDocumentContents(Platform::FloatRect(Platform::FloatPoint::zero(), WebCore::FloatSize(scrollableArea->contentsSize()))).size();
        m_viewportSize = viewportAccessor->roundToPixelFromDocumentContents(WebCore::FloatRect(scrollableArea->visibleContentRect(ScrollableArea::ExcludeScrollbars))).size();
        m_documentViewportRect = enclosingIntRect(box->absoluteClippedOverflowRect());

        m_scrollsHorizontally = box->scrollWidth() != box->clientWidth();
        m_scrollsVertically = box->scrollHeight() != box->clientHeight();

        // Check the overflow if its not an input field because overflow can be set to hidden etc. by the content.
        if (!DOMSupport::isShadowHostTextInputElement(box->node())) {
            m_scrollsHorizontally = m_scrollsHorizontally && box->scrollsOverflowX();
            m_scrollsVertically = m_scrollsVertically && box->scrollsOverflowY();
        }

        m_scrollTarget = BlockElement;

        // Both caches below are self-exclusive.
        if (m_layer->usesCompositedScrolling()) {
            m_forceContentToBeHorizontallyScrollable = m_scrollsHorizontally;
            m_forceContentToBeVerticallyScrollable = m_scrollsVertically;
            // Force content to be scrollable even if it doesn't need to scroll in either direction.
            if (!m_scrollsHorizontally && !m_scrollsVertically) {
                if (box->scrollsOverflowY())
                    m_forceContentToBeVerticallyScrollable = true;
                else if (box->scrollsOverflowX()) // If it's already forced scrollable vertically, don't force it to scroll horizontally
                    m_forceContentToBeHorizontallyScrollable = true;
            }
            m_supportsCompositedScrolling = true;
            ASSERT(m_layer->backing()->hasScrollingLayer());
            m_camouflagedCompositedScrollableLayer = reinterpret_cast<unsigned>(m_layer->backing()->scrollingContentsLayer()->platformLayer());
            m_cachedCompositedScrollableLayer = m_layer->backing()->scrollingContentsLayer()->platformLayer();
            ASSERT(!m_cachedNonCompositedScrollableNode);
        } else {
            m_camouflagedCompositedScrollableLayer = reinterpret_cast<unsigned>(m_layer->enclosingElement());
            m_cachedNonCompositedScrollableNode = m_layer->enclosingElement();
            ASSERT(!m_cachedCompositedScrollableLayer);
        }
    }
}

InRegionScrollableArea::InRegionScrollableArea(WebPagePrivate* webPage, RenderLayer* layer)
    : m_webPage(webPage)
    , m_layer(layer)
    , m_document(0)
    , m_hasWindowVisibleRectCalculated(false)
{
    ASSERT(webPage);
    ASSERT(layer);
    m_isNull = false;

    // Add a pointer to the enclosing document as the pointer to layer or node along the way may become invalid.
    if (m_layer->enclosingElement())
        m_document = m_layer->enclosingElement()->document();

    // FIXME: Add an ASSERT here as the 'layer' must be scrollable.

    RenderObject* layerRenderer = layer->renderer();
    ASSERT(layerRenderer);

    if (layerRenderer->isRenderView()) { // #document case

        RenderView* renderView = toRenderView(layerRenderer);
        ASSERT(renderView);

        FrameView* view = toRenderView(layerRenderer)->frameView();
        ASSERT(view);

        Frame* frame = view->frame();
        ASSERT_UNUSED(frame, frame);

        m_scrollPosition = m_webPage->mapToTransformed(view->scrollPosition());
        m_contentsSize = m_webPage->mapToTransformed(view->contentsSize());
        m_viewportSize = m_webPage->mapToTransformed(view->visibleContentRect(ScrollableArea::ExcludeScrollbars)).size();
        m_documentViewportRect = view->frameRect();

        m_scrollsHorizontally = view->contentsWidth() > view->visibleWidth();
        m_scrollsVertically = view->contentsHeight() > view->visibleHeight();

        m_supportsCompositedScrolling = true;

        m_scrollTarget = InnerFrame;

        ASSERT(!m_cachedNonCompositedScrollableNode);

        m_camouflagedCompositedScrollableLayer = reinterpret_cast<unsigned>(renderView->compositor()->scrollLayer()->platformLayer());
        m_cachedCompositedScrollableLayer = renderView->compositor()->scrollLayer()->platformLayer();

    } else { // RenderBox-based elements case (scrollable boxes (div's, p's, textarea's, etc)).

        RenderBox* box = m_layer->renderBox();
        ASSERT(box);
        ASSERT(InRegionScrollerPrivate::canScrollRenderBox(box));

        ScrollableArea* scrollableArea = static_cast<ScrollableArea*>(m_layer);
        m_scrollPosition = m_webPage->mapToTransformed(scrollableArea->scrollPosition());
        m_contentsSize = m_webPage->mapToTransformed(scrollableArea->contentsSize());
        m_viewportSize = m_webPage->mapToTransformed(scrollableArea->visibleContentRect(ScrollableArea::ExcludeScrollbars)).size();
        m_documentViewportRect = enclosingIntRect(box->absoluteClippedOverflowRect());

        m_scrollsHorizontally = box->scrollWidth() != box->clientWidth();
        m_scrollsVertically = box->scrollHeight() != box->clientHeight();

        // Check the overflow if its not an input field because overflow can be set to hidden etc. by the content.
        if (!box->node() || !box->node()->rendererIsEditable()) {
            m_scrollsHorizontally = m_scrollsHorizontally && box->scrollsOverflowX();
            m_scrollsVertically = m_scrollsVertically && box->scrollsOverflowY();
        }

        m_scrollTarget = BlockElement;

        // Both caches below are self-exclusive.
        if (m_layer->usesCompositedScrolling()) {
            m_forceContentToBeVerticallyScrollable = true;
            m_supportsCompositedScrolling = true;
            ASSERT(m_layer->backing()->hasScrollingLayer());
            m_camouflagedCompositedScrollableLayer = reinterpret_cast<unsigned>(m_layer->backing()->scrollingContentsLayer()->platformLayer());
            m_cachedCompositedScrollableLayer = m_layer->backing()->scrollingContentsLayer()->platformLayer();
            ASSERT(!m_cachedNonCompositedScrollableNode);
        } else {
            m_camouflagedCompositedScrollableLayer = reinterpret_cast<unsigned>(m_layer->enclosingElement());
            m_cachedNonCompositedScrollableNode = m_layer->enclosingElement();
            ASSERT(!m_cachedCompositedScrollableLayer);
        }
    }
}