C++ ThebesLayer类代码示例

void
ReadbackProcessor::BuildUpdatesForLayer(ReadbackLayer* aLayer)
{
  if (!aLayer->mSink)
    return;

  nsIntPoint offset;
  Layer* newBackground = FindBackgroundLayer(aLayer, &offset);
  if (!newBackground) {
    aLayer->SetUnknown();
    return;
  }

  if (newBackground->GetType() == Layer::TYPE_COLOR) {
    ColorLayer* colorLayer = static_cast<ColorLayer*>(newBackground);
    if (aLayer->mBackgroundColor != colorLayer->GetColor()) {
      aLayer->mBackgroundLayer = nullptr;
      aLayer->mBackgroundColor = colorLayer->GetColor();
      NS_ASSERTION(aLayer->mBackgroundColor.a == 1.0,
                   "Color layer said it was opaque!");
      nsRefPtr<gfxContext> ctx =
          aLayer->mSink->BeginUpdate(aLayer->GetRect(),
                                     aLayer->AllocateSequenceNumber());
      if (ctx) {
        ctx->SetColor(aLayer->mBackgroundColor);
        nsIntSize size = aLayer->GetSize();
        ctx->Rectangle(gfxRect(0, 0, size.width, size.height));
        ctx->Fill();
        aLayer->mSink->EndUpdate(ctx, aLayer->GetRect());
      }
    }
  } else {
    NS_ASSERTION(newBackground->AsThebesLayer(), "Must be ThebesLayer");
    ThebesLayer* thebesLayer = static_cast<ThebesLayer*>(newBackground);
    // updateRect is relative to the ThebesLayer
    nsIntRect updateRect = aLayer->GetRect() - offset;
    if (thebesLayer != aLayer->mBackgroundLayer ||
        offset != aLayer->mBackgroundLayerOffset) {
      aLayer->mBackgroundLayer = thebesLayer;
      aLayer->mBackgroundLayerOffset = offset;
      aLayer->mBackgroundColor = gfxRGBA(0,0,0,0);
      thebesLayer->SetUsedForReadback(true);
    } else {
      nsIntRegion invalid;
      invalid.Sub(updateRect, thebesLayer->GetValidRegion());
      updateRect = invalid.GetBounds();
    }

    Update update = { aLayer, updateRect, aLayer->AllocateSequenceNumber() };
    mAllUpdates.AppendElement(update);
  }
}

void
ContainerLayer::DidRemoveChild(Layer* aLayer)
{
  ThebesLayer* tl = aLayer->AsThebesLayer();
  if (tl && tl->UsedForReadback()) {
    for (Layer* l = mFirstChild; l; l = l->GetNextSibling()) {
      if (l->GetType() == TYPE_READBACK) {
        static_cast<ReadbackLayer*>(l)->NotifyThebesLayerRemoved(tl);
      }
    }
  }
  if (aLayer->GetType() == TYPE_READBACK) {
    static_cast<ReadbackLayer*>(aLayer)->NotifyRemoved();
  }
}

/* static */ void
LayerManagerComposite::ComputeRenderIntegrityInternal(Layer* aLayer,
                                                      nsIntRegion& aScreenRegion,
                                                      nsIntRegion& aLowPrecisionScreenRegion,
                                                      const Matrix4x4& aTransform)
{
  if (aLayer->GetOpacity() <= 0.f ||
      (aScreenRegion.IsEmpty() && aLowPrecisionScreenRegion.IsEmpty())) {
    return;
  }

  // If the layer's a container, recurse into all of its children
  ContainerLayer* container = aLayer->AsContainerLayer();
  if (container) {
    // Accumulate the transform of intermediate surfaces
    Matrix4x4 transform = aTransform;
    if (container->UseIntermediateSurface()) {
      transform = aLayer->GetEffectiveTransform();
      transform = aTransform * transform;
    }
    for (Layer* child = aLayer->GetFirstChild(); child;
         child = child->GetNextSibling()) {
      ComputeRenderIntegrityInternal(child, aScreenRegion, aLowPrecisionScreenRegion, transform);
    }
    return;
  }

  // Only thebes layers can be incomplete
  ThebesLayer* thebesLayer = aLayer->AsThebesLayer();
  if (!thebesLayer) {
    return;
  }

  // See if there's any incomplete rendering
  nsIntRegion incompleteRegion = aLayer->GetEffectiveVisibleRegion();
  incompleteRegion.Sub(incompleteRegion, thebesLayer->GetValidRegion());

  if (!incompleteRegion.IsEmpty()) {
    // Calculate the transform to get between screen and layer space
    Matrix4x4 transformToScreen = aLayer->GetEffectiveTransform();
    transformToScreen = aTransform * transformToScreen;

    SubtractTransformedRegion(aScreenRegion, incompleteRegion, transformToScreen);

    // See if there's any incomplete low-precision rendering
    TiledLayerComposer* composer = nullptr;
    LayerComposite* shadow = aLayer->AsLayerComposite();
    if (shadow) {
      composer = shadow->GetTiledLayerComposer();
      if (composer) {
        incompleteRegion.Sub(incompleteRegion, composer->GetValidLowPrecisionRegion());
        if (!incompleteRegion.IsEmpty()) {
          SubtractTransformedRegion(aLowPrecisionScreenRegion, incompleteRegion, transformToScreen);
        }
      }
    }

    // If we can't get a valid low precision region, assume it's the same as
    // the high precision region.
    if (!composer) {
      SubtractTransformedRegion(aLowPrecisionScreenRegion, incompleteRegion, transformToScreen);
    }
  }
}