C++ HistoryItem::contentsSize方法代码示例

void FrameLoaderClientBlackBerry::restoreViewState()
{
    if (!isMainFrame())
        return;

    HistoryItem* currentItem = m_frame->loader()->history()->currentItem();
    ASSERT(currentItem);

    if (!currentItem)
        return;

    // WebPagePrivate is messing up FrameView::wasScrolledByUser() by sending
    // scroll events that look like they were user generated all the time.
    //
    // Even if the user did not scroll, FrameView is gonna think they did.
    // So we use our own bookkeeping code to keep track of whether we were
    // actually scrolled by the user during load.
    //
    // If the user did scroll though, all are going to be in agreement about
    // that, and the worst thing that could happen is that
    // HistoryController::restoreScrollPositionAndViewState calls
    // setScrollPosition with the the same point, which is a NOOP.
    IntSize contentsSize = currentItem->contentsSize();
    IntPoint scrollPosition = currentItem->scrollPoint();
    if (m_webPagePrivate->m_userPerformedManualScroll)
        scrollPosition = m_webPagePrivate->scrollPosition();

    // We need to reset this variable after the view state has been restored.
    m_webPagePrivate->m_didRestoreFromPageCache = false;
    HistoryItemViewState& viewState = currentItem->viewState();

    // Restore the meta first.
    m_webPagePrivate->m_minimumScale = viewState.minimumScale;
    m_webPagePrivate->m_maximumScale = viewState.maximumScale;
    m_webPagePrivate->m_userScalable = viewState.isUserScalable;
    // Also, try to keep the users zoom if any.
    double scale = viewState.scale;
    bool shouldReflowBlock = viewState.shouldReflowBlock;
    if (m_webPagePrivate->m_userPerformedManualZoom) {
        scale = m_webPagePrivate->currentScale();
        shouldReflowBlock = m_webPagePrivate->m_shouldReflowBlock;
    }

    bool scrollChanged = scrollPosition != m_webPagePrivate->scrollPosition();
    bool scaleChanged = scale != m_webPagePrivate->currentScale();
    bool reflowChanged = shouldReflowBlock != m_webPagePrivate->m_shouldReflowBlock;
    bool orientationChanged = viewState.orientation % 180 != m_webPagePrivate->mainFrame()->orientation() % 180;

    if (!scrollChanged && !scaleChanged && !reflowChanged && !orientationChanged)
        return;

    // When rotate happens, only zoom when previous page was zoomToFitScale, otherwise keep old scale.
    if (orientationChanged && viewState.isZoomToFitScale)
        scale = BlackBerry::Platform::Graphics::Screen::primaryScreen()->width() * scale / static_cast<double>(BlackBerry::Platform::Graphics::Screen::primaryScreen()->height());
    m_webPagePrivate->m_backingStore->d->suspendScreenAndBackingStoreUpdates(); // don't flash checkerboard for the setScrollPosition call
    m_frame->view()->setContentsSizeFromHistory(contentsSize);

    // Here we need to set scroll position what we asked for.
    // So we use ScrollView::setCanOverscroll(true).
    bool oldCanOverscroll = m_frame->view()->canOverScroll();
    m_frame->view()->setCanOverscroll(true);
    m_webPagePrivate->setScrollPosition(scrollPosition);
    m_frame->view()->setCanOverscroll(oldCanOverscroll);

    m_webPagePrivate->m_shouldReflowBlock = viewState.shouldReflowBlock;

    // Will restore updates to backingstore guaranteed!
    if (!m_webPagePrivate->zoomAboutPoint(scale, m_frame->view()->scrollPosition(), true /* enforceScaleClamping */, true /*forceRendering*/, true /*isRestoringZoomLevel*/)) {
        // If we're already at that scale, then we should still force rendering since
        // our scroll position changed.
        m_webPagePrivate->m_backingStore->d->renderVisibleContents();

        // We need to notify the client of the scroll position and content size change(s) above even if we didn't scale.
        m_webPagePrivate->notifyTransformedContentsSizeChanged();
        m_webPagePrivate->notifyTransformedScrollChanged();
    }
}