C++ LayerMetricsWrapper::Metrics方法代码示例

bool
ClientTiledPaintedLayer::UseFastPath()
{
  LayerMetricsWrapper scrollAncestor;
  GetAncestorLayers(&scrollAncestor, nullptr);
  if (!scrollAncestor) {
    return true;
  }
  const FrameMetrics& parentMetrics = scrollAncestor.Metrics();

  bool multipleTransactionsNeeded = gfxPlatform::GetPlatform()->UseProgressivePaint()
                                 || gfxPrefs::UseLowPrecisionBuffer()
                                 || !parentMetrics.GetCriticalDisplayPort().IsEmpty();
  bool isFixed = GetIsFixedPosition() || GetParent()->GetIsFixedPosition();
  return !multipleTransactionsNeeded || isFixed || parentMetrics.GetDisplayPort().IsEmpty();
}

bool
ClientTiledPaintedLayer::UseProgressiveDraw() {
  if (!gfxPlatform::GetPlatform()->UseProgressivePaint()) {
    // pref is disabled, so never do progressive
    return false;
  }

  if (!mContentClient->GetTiledBuffer()->SupportsProgressiveUpdate()) {
    return false;
  }

  if (ClientManager()->HasShadowTarget()) {
    // This condition is true when we are in a reftest scenario. We don't want
    // to draw progressively here because it can cause intermittent reftest
    // failures because the harness won't wait for all the tiles to be drawn.
    return false;
  }

  if (mPaintData.mCriticalDisplayPort.IsEmpty()) {
    // This catches three scenarios:
    // 1) This layer doesn't have a scrolling ancestor
    // 2) This layer is subject to OMTA transforms
    // 3) Low-precision painting is disabled
    // In all of these cases, we don't want to draw this layer progressively.
    return false;
  }

  if (GetIsFixedPosition() || GetParent()->GetIsFixedPosition()) {
    // This layer is fixed-position and so even if it does have a scrolling
    // ancestor it will likely be entirely on-screen all the time, so we
    // should draw it all at once
    return false;
  }

  if (ClientManager()->AsyncPanZoomEnabled()) {
    LayerMetricsWrapper scrollAncestor;
    GetAncestorLayers(&scrollAncestor, nullptr, nullptr);
    MOZ_ASSERT(scrollAncestor); // because mPaintData.mCriticalDisplayPort is non-empty
    const FrameMetrics& parentMetrics = scrollAncestor.Metrics();
    if (!IsScrollingOnCompositor(parentMetrics)) {
      return false;
    }
  }

  return true;
}

bool
ClientTiledPaintedLayer::UseProgressiveDraw() {
    if (!gfxPrefs::ProgressivePaint()) {
        // pref is disabled, so never do progressive
        return false;
    }

    if (!mContentClient->GetTiledBuffer()->SupportsProgressiveUpdate()) {
        return false;
    }

    if (ClientManager()->HasShadowTarget()) {
        // This condition is true when we are in a reftest scenario. We don't want
        // to draw progressively here because it can cause intermittent reftest
        // failures because the harness won't wait for all the tiles to be drawn.
        return false;
    }

    if (GetIsFixedPosition() || GetParent()->GetIsFixedPosition()) {
        // This layer is fixed-position and so even if it does have a scrolling
        // ancestor it will likely be entirely on-screen all the time, so we
        // should draw it all at once
        return false;
    }

    if (mPaintData.mHasTransformAnimation) {
        // The compositor is going to animate this somehow, so we want it all
        // on the screen at once.
        return false;
    }

    if (ClientManager()->AsyncPanZoomEnabled()) {
        LayerMetricsWrapper scrollAncestor;
        GetAncestorLayers(&scrollAncestor, nullptr, nullptr);
        MOZ_ASSERT(scrollAncestor); // because mPaintData.mCriticalDisplayPort is set
        if (!scrollAncestor) {
            return false;
        }
        const FrameMetrics& parentMetrics = scrollAncestor.Metrics();
        if (!IsScrollingOnCompositor(parentMetrics)) {
            return false;
        }
    }

    return true;
}

bool
ClientTiledPaintedLayer::UseFastPath()
{
  LayerMetricsWrapper scrollAncestor;
  GetAncestorLayers(&scrollAncestor, nullptr);
  if (!scrollAncestor) {
    return true;
  }
  const FrameMetrics& parentMetrics = scrollAncestor.Metrics();

  bool multipleTransactionsNeeded = gfxPlatform::GetPlatform()->UseProgressivePaint()
                                 || gfxPrefs::UseLowPrecisionBuffer()
                                 || !parentMetrics.GetCriticalDisplayPort().IsEmpty();
  bool isFixed = GetIsFixedPosition() || GetParent()->GetIsFixedPosition();
  bool isScrollable = parentMetrics.IsScrollable();

  return !multipleTransactionsNeeded || isFixed || !isScrollable
#if !defined(MOZ_WIDGET_ANDROID) || defined(MOZ_ANDROID_APZ)
         || !IsScrollingOnCompositor(parentMetrics)
#endif
         ;
}