WebCore/platform/ScrollableArea.cpp

/*
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 * Copyright (C) 2008, 2011 Apple Inc. All Rights Reserved.
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#include "config.h"
#include "ScrollableArea.h"

#include "GraphicsContext.h"
#include "GraphicsLayer.h"
#include "FloatPoint.h"
#include "PlatformWheelEvent.h"
#include "ScrollAnimator.h"
#include "ScrollbarTheme.h"
#include <wtf/PassOwnPtr.h>

namespace WebCore {

ScrollableArea::ScrollableArea()
    : m_scrollAnimator(ScrollAnimator::create(this))
    , m_constrainsScrollingToContentEdge(true)
    , m_inLiveResize(false)
    , m_verticalScrollElasticity(ScrollElasticityNone)
    , m_horizontalScrollElasticity(ScrollElasticityNone)
{
}

ScrollableArea::~ScrollableArea()
{
}

bool ScrollableArea::scroll(ScrollDirection direction, ScrollGranularity granularity, float multiplier)
{
    ScrollbarOrientation orientation;
    Scrollbar* scrollbar;
    if (direction == ScrollUp || direction == ScrollDown) {
        orientation = VerticalScrollbar;
        scrollbar = verticalScrollbar();
    } else {
        orientation = HorizontalScrollbar;
        scrollbar = horizontalScrollbar();
    }

    if (!scrollbar)
        return false;

    float step = 0;
    switch (granularity) {
    case ScrollByLine:
        step = scrollbar->lineStep();
        break;
    case ScrollByPage:
        step = scrollbar->pageStep();
        break;
    case ScrollByDocument:
        step = scrollbar->totalSize();
        break;
    case ScrollByPixel:
        step = scrollbar->pixelStep();
        break;
    }

    if (direction == ScrollUp || direction == ScrollLeft)
        multiplier = -multiplier;

    return m_scrollAnimator->scroll(orientation, granularity, step, multiplier);
}

void ScrollableArea::scrollToOffsetWithoutAnimation(const FloatPoint& offset)
{
    m_scrollAnimator->scrollToOffsetWithoutAnimation(offset);
}

void ScrollableArea::scrollToOffsetWithoutAnimation(ScrollbarOrientation orientation, float offset)
{
    if (orientation == HorizontalScrollbar)
        scrollToXOffsetWithoutAnimation(offset);
    else
        scrollToYOffsetWithoutAnimation(offset);
}

void ScrollableArea::scrollToXOffsetWithoutAnimation(float x)
{
    scrollToOffsetWithoutAnimation(FloatPoint(x, m_scrollAnimator->currentPosition().y()));
}

void ScrollableArea::scrollToYOffsetWithoutAnimation(float y)
{
    scrollToOffsetWithoutAnimation(FloatPoint(m_scrollAnimator->currentPosition().x(), y));
}

void ScrollableArea::handleWheelEvent(PlatformWheelEvent& wheelEvent)
{
    m_scrollAnimator->handleWheelEvent(wheelEvent);
}

#if ENABLE(GESTURE_EVENTS)
void ScrollableArea::handleGestureEvent(const PlatformGestureEvent& gestureEvent)
{
    m_scrollAnimator->handleGestureEvent(gestureEvent);
}
#endif

void ScrollableArea::setScrollOffsetFromAnimation(const IntPoint& offset)
{
    // Tell the derived class to scroll its contents.
    setScrollOffset(offset);

    Scrollbar* verticalScrollbar = this->verticalScrollbar();

    // Tell the scrollbars to update their thumb postions.
    if (Scrollbar* horizontalScrollbar = this->horizontalScrollbar()) {
        horizontalScrollbar->offsetDidChange();
        if (horizontalScrollbar->isOverlayScrollbar()) {
            if (!verticalScrollbar)
                horizontalScrollbar->invalidate();
            else {
                // If there is both a horizontalScrollbar and a verticalScrollbar,
                // then we must also invalidate the corner between them.
                IntRect boundsAndCorner = horizontalScrollbar->boundsRect();
                boundsAndCorner.setWidth(boundsAndCorner.width() + verticalScrollbar->width());
                horizontalScrollbar->invalidateRect(boundsAndCorner);
            }
        }
    }
    if (verticalScrollbar) {
        verticalScrollbar->offsetDidChange();
        if (verticalScrollbar->isOverlayScrollbar())
            verticalScrollbar->invalidate();
    }
}

void ScrollableArea::willStartLiveResize()
{
    if (m_inLiveResize)
        return;
    m_inLiveResize = true;
    scrollAnimator()->willStartLiveResize();
}

void ScrollableArea::willEndLiveResize()
{
    if (!m_inLiveResize)
        return;
    m_inLiveResize = false;
    scrollAnimator()->willEndLiveResize();
}

void ScrollableArea::didAddVerticalScrollbar(Scrollbar* scrollbar)
{
    scrollAnimator()->didAddVerticalScrollbar(scrollbar);
}

void ScrollableArea::willRemoveVerticalScrollbar(Scrollbar* scrollbar)
{
    scrollAnimator()->willRemoveVerticalScrollbar(scrollbar);
}

void ScrollableArea::didAddHorizontalScrollbar(Scrollbar* scrollbar)
{
    scrollAnimator()->didAddHorizontalScrollbar(scrollbar);
}

void ScrollableArea::willRemoveHorizontalScrollbar(Scrollbar* scrollbar)
{
    scrollAnimator()->willRemoveHorizontalScrollbar(scrollbar);
}

bool ScrollableArea::hasOverlayScrollbars() const
{
    return (verticalScrollbar() && verticalScrollbar()->isOverlayScrollbar())
        || (horizontalScrollbar() && horizontalScrollbar()->isOverlayScrollbar());
}

void ScrollableArea::invalidateScrollbar(Scrollbar* scrollbar, const IntRect& rect)
{
#if USE(ACCELERATED_COMPOSITING)
    if (scrollbar == horizontalScrollbar()) {
        if (GraphicsLayer* graphicsLayer = layerForHorizontalScrollbar()) {
            graphicsLayer->setNeedsDisplay();
            return;
        }
    } else if (scrollbar == verticalScrollbar()) {
        if (GraphicsLayer* graphicsLayer = layerForVerticalScrollbar()) {
            graphicsLayer->setNeedsDisplay();
            return;
        }
    }
#endif
    invalidateScrollbarRect(scrollbar, rect);
}

void ScrollableArea::invalidateScrollCorner()
{
#if USE(ACCELERATED_COMPOSITING)
    if (GraphicsLayer* graphicsLayer = layerForScrollCorner()) {
        graphicsLayer->setNeedsDisplay();
        return;
    }
#endif
    invalidateScrollCornerRect(scrollCornerRect());
}

bool ScrollableArea::hasLayerForHorizontalScrollbar() const
{
#if USE(ACCELERATED_COMPOSITING)
    return layerForHorizontalScrollbar();
#else
    return false;
#endif
}

bool ScrollableArea::hasLayerForVerticalScrollbar() const
{
#if USE(ACCELERATED_COMPOSITING)
    return layerForVerticalScrollbar();
#else
    return false;
#endif
}

bool ScrollableArea::hasLayerForScrollCorner() const
{
#if USE(ACCELERATED_COMPOSITING)
    return layerForScrollCorner();
#else
    return false;
#endif
}

} // namespace WebCore