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/*
* Copyright (C) 2011,2014 Igalia S.L.
* Copyright (C) 2011 Samsung Electronics
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "config.h"
#include "BackingStoreBackendCairoImpl.h"
#if USE(CAIRO)
#include "CairoUtilities.h"
namespace WebCore {
BackingStoreBackendCairoImpl::BackingStoreBackendCairoImpl(cairo_surface_t* surface, const IntSize& size)
: BackingStoreBackendCairo(size)
{
m_surface = surface;
// We keep two copies of the surface here, which will double the memory usage, but increase
// scrolling performance since we do not have to keep reallocating a memory region during
// quick scrolling requests.
double xScale, yScale;
cairoSurfaceGetDeviceScale(m_surface.get(), xScale, yScale);
IntSize scaledSize = size;
scaledSize.scale(xScale, yScale);
m_scrollSurface = adoptRef(cairo_surface_create_similar(surface, CAIRO_CONTENT_COLOR_ALPHA, scaledSize.width(), scaledSize.height()));
}
BackingStoreBackendCairoImpl::~BackingStoreBackendCairoImpl()
{
}
void BackingStoreBackendCairoImpl::scroll(const IntRect& scrollRect, const IntSize& scrollOffset)
{
IntRect targetRect = scrollRect;
targetRect.move(scrollOffset);
targetRect.shiftMaxXEdgeTo(targetRect.maxX() - scrollOffset.width());
targetRect.shiftMaxYEdgeTo(targetRect.maxY() - scrollOffset.height());
if (targetRect.isEmpty())
return;
copyRectFromOneSurfaceToAnother(m_surface.get(), m_scrollSurface.get(), scrollOffset, targetRect);
copyRectFromOneSurfaceToAnother(m_scrollSurface.get(), m_surface.get(), IntSize(), targetRect);
}
} // namespace WebCore
#endif // USE(CAIRO)
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