CanvasLayerTextureUpdater.cpp   [plain text]

/*
 * Copyright (C) 2011 Google Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 *
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 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
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 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS 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 APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
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#include "config.h"

#if USE(ACCELERATED_COMPOSITING)

#include "CanvasLayerTextureUpdater.h"

#include "GraphicsContext.h"
#include "LayerPainterChromium.h"
#include "PlatformContextSkia.h"
#include "TraceEvent.h"

namespace WebCore {

CanvasLayerTextureUpdater::CanvasLayerTextureUpdater(PassOwnPtr<LayerPainterChromium> painter)
    : m_painter(painter)
{
}

CanvasLayerTextureUpdater::~CanvasLayerTextureUpdater()
{
}

void CanvasLayerTextureUpdater::paintContents(GraphicsContext& context, PlatformContextSkia& platformContext, const IntRect& contentRect, float contentsScale, IntRect& resultingOpaqueRect)
{
    context.translate(-contentRect.x(), -contentRect.y());
    {
        TRACE_EVENT("LayerTextureUpdaterCanvas::paint", this, 0);

        IntRect scaledContentRect = contentRect;

        if (contentsScale != 1.0) {
            context.save();
            context.scale(FloatSize(contentsScale, contentsScale));

            FloatRect rect = contentRect;
            rect.scale(1 / contentsScale);
            scaledContentRect = enclosingIntRect(rect);
        }

        // Record transform prior to painting, as all opaque tracking will be
        // relative to this current value.
        AffineTransform canvasToContentTransform = context.getCTM().inverse();

        m_painter->paint(context, scaledContentRect);

        // Transform tracked opaque paints back to our layer's content space.
        ASSERT(canvasToContentTransform.isInvertible());
        ASSERT(canvasToContentTransform.preservesAxisAlignment());
        FloatRect opaqueCanvasRect = platformContext.opaqueRegion().asRect();
        resultingOpaqueRect = enclosedIntRect(canvasToContentTransform.mapRect(opaqueCanvasRect));

        if (contentsScale != 1.0)
            context.restore();
    }
    m_contentRect = contentRect;
}

} // namespace WebCore
#endif // USE(ACCELERATED_COMPOSITING)