Source/core/platform/graphics/OpaqueRectTrackingContentLayerDelegate.cpp

/*
 * Copyright (C) 2012 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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 * 1.  Redistributions of source code must retain the above copyright
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 *
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 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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 * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
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#include "config.h"

#include "core/platform/graphics/OpaqueRectTrackingContentLayerDelegate.h"

#include "core/platform/graphics/GraphicsContext.h"
#include "platform/EventTracer.h"
#include "platform/geometry/IntRect.h"
#include "platform/transforms/AffineTransform.h"
#include "public/platform/WebFloatRect.h"
#include "public/platform/WebRect.h"

using blink::WebFloatRect;
using blink::WebRect;

namespace WebCore {

OpaqueRectTrackingContentLayerDelegate::OpaqueRectTrackingContentLayerDelegate(GraphicsContextPainter* painter)
    : m_painter(painter)
    , m_opaque(false)
{
}

OpaqueRectTrackingContentLayerDelegate::~OpaqueRectTrackingContentLayerDelegate()
{
}

void OpaqueRectTrackingContentLayerDelegate::paintContents(SkCanvas* canvas, const WebRect& clip, bool canPaintLCDText, WebFloatRect& opaque)
{
    static const unsigned char* annotationsEnabled = 0;
    if (UNLIKELY(!annotationsEnabled))
        annotationsEnabled = EventTracer::getTraceCategoryEnabledFlag(TRACE_DISABLED_BY_DEFAULT("blink.graphics_context_annotations"));

    GraphicsContext context(canvas);
    context.setTrackOpaqueRegion(!m_opaque);
    context.setCertainlyOpaque(m_opaque);
    context.setShouldSmoothFonts(canPaintLCDText);

    if (*annotationsEnabled)
        context.setAnnotationMode(AnnotateAll);

    // 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, clip);

    // Transform tracked opaque paints back to our layer's content space.
    ASSERT(canvasToContentTransform.isInvertible());
    ASSERT(canvasToContentTransform.preservesAxisAlignment());
    opaque = canvasToContentTransform.mapRect(context.opaqueRegion().asRect());
}

}