gecko-dev/gfx/layers/FrameMetrics.h

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef GFX_FRAMEMETRICS_H
#define GFX_FRAMEMETRICS_H
#include "gfxPoint.h"
#include "gfxTypes.h"
#include "nsRect.h"
#include "mozilla/gfx/Rect.h"
namespace mozilla {
namespace layers {
/**
* The viewport and displayport metrics for the painted frame at the
* time of a layer-tree transaction. These metrics are especially
* useful for shadow layers, because the metrics values are updated
* atomically with new pixels.
*/
struct THEBES_API FrameMetrics {
public:
// We use IDs to identify frames across processes.
typedef PRUint64 ViewID;
static const ViewID NULL_SCROLL_ID; // This container layer does not scroll.
static const ViewID ROOT_SCROLL_ID; // This is the root scroll frame.
static const ViewID START_SCROLL_ID; // This is the ID that scrolling subframes
// will begin at.
FrameMetrics()
: mViewport(0, 0, 0, 0)
, mContentRect(0, 0, 0, 0)
, mViewportScrollOffset(0, 0)
, mScrollId(NULL_SCROLL_ID)
, mCSSContentRect(0, 0, 0, 0)
, mResolution(1, 1)
{}
// Default copy ctor and operator= are fine
bool operator==(const FrameMetrics& aOther) const
{
return (mViewport.IsEqualEdges(aOther.mViewport) &&
mViewportScrollOffset == aOther.mViewportScrollOffset &&
mDisplayPort.IsEqualEdges(aOther.mDisplayPort) &&
mScrollId == aOther.mScrollId);
}
bool operator!=(const FrameMetrics& aOther) const
{
return !operator==(aOther);
}
bool IsDefault() const
{
return (FrameMetrics() == *this);
}
bool IsRootScrollable() const
{
return mScrollId == ROOT_SCROLL_ID;
}
bool IsScrollable() const
{
return mScrollId != NULL_SCROLL_ID;
}
// These are all in layer coordinate space.
nsIntRect mViewport;
nsIntRect mContentRect;
nsIntPoint mViewportScrollOffset;
nsIntRect mDisplayPort;
ViewID mScrollId;
// Consumers often want to know the origin/size before scaling to pixels
// so we record this as well.
gfx::Rect mCSSContentRect;
// This represents the resolution at which the associated layer
// will been rendered.
gfxSize mResolution;
};
}
}
#endif /* GFX_FRAMEMETRICS_H */