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/*
* Copyright (C) 2010 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "DragScrollTimer.h"
#include "FrameView.h"
using namespace WebCore;
namespace WebKit {
// Computes the distance from a point outside a rect to the nearest edge of the rect.
static IntSize distanceToRect(const IntPoint& point, const IntRect& rect)
{
int dx = 0, dy = 0;
if (point.x() < rect.x())
dx = point.x() - rect.x();
else if (rect.maxX() < point.x())
dx = point.x() - rect.maxX();
if (point.y() < rect.y())
dy = point.y() - rect.y();
else if (rect.maxY() < point.y())
dy = point.y() - rect.maxY();
return IntSize(dx, dy);
}
DragScrollTimer::DragScrollTimer()
: m_timer(this, &DragScrollTimer::fired)
, m_view(0)
, m_scrolling(false)
{
}
DragScrollTimer::~DragScrollTimer()
{
// We do this for detecting dead object earlier
stop();
}
void DragScrollTimer::stop()
{
m_timer.stop();
m_view = 0;
m_scrolling = false;
}
void DragScrollTimer::scroll()
{
m_view->scrollBy(m_lastDistance);
m_scrolling = true;
}
void DragScrollTimer::update()
{
if (shouldScroll())
scroll();
else
stop();
}
void DragScrollTimer::triggerScroll(FrameView* view, const WebPoint& location)
{
if (!view)
return;
// Approximates Safari
static const double scrollStartDelay = 0.2;
m_view = view;
m_lastDistance = scrollDistanceFor(view, location);
if (m_scrolling)
update();
else if (shouldScroll() && !m_timer.isActive())
m_timer.startOneShot(scrollStartDelay);
}
IntSize DragScrollTimer::scrollDistanceFor(FrameView* view, const WebPoint& location) const
{
static const int scrollMargin = 30;
IntRect bounds(0, 0, view->visibleWidth(), view->visibleHeight());
if (!bounds.contains(location))
return IntSize(0, 0); // The location is outside the border belt.
bounds.setY(bounds.y() + scrollMargin);
bounds.setHeight(bounds.height() - scrollMargin * 2);
bounds.setX(bounds.x() + scrollMargin);
bounds.setWidth(bounds.width() - scrollMargin * 2);
if (bounds.contains(location))
return IntSize(0, 0); // The location is inside the border belt.
// The location is over the border belt.
return distanceToRect(location, bounds);
}
} // namespace WebKit
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