Ejemplos de Layer::GetFirstChild en C++ (Cpp)

Ejemplo n.º 1

Archivo: CompositorParent.cpp Proyecto: zpao/mozilla-central

// Do a breadth-first search to find the first layer in the tree that is
// scrollable.
Layer*
CompositorParent::GetPrimaryScrollableLayer()
{
  Layer* root = mLayerManager->GetRoot();

  // FIXME: We're currently getting passed layers that are not part of our content, but
  // we are drawing them anyway. This is causing severe rendering corruption to our background
  // and checkerboarding. The real fix here is to assert that we don't have any useless layers
  // and ensure that layout isn't giving us any. This is being tracked in bug 728284.
  // For now just clip them to the empty rect so we don't draw them.
  Layer* discardLayer = root->GetFirstChild();

  while (discardLayer) {
    if (!discardLayer->AsContainerLayer()) {
      discardLayer->IntersectClipRect(nsIntRect());
      SetShadowProperties(discardLayer);
    }
    discardLayer = discardLayer->GetNextSibling();
  }

  nsTArray<Layer*> queue;
  queue.AppendElement(root);
  while (queue.Length()) {
    ContainerLayer* containerLayer = queue[0]->AsContainerLayer();
    queue.RemoveElementAt(0);
    if (!containerLayer) {
      continue;
    }

    const FrameMetrics& frameMetrics = containerLayer->GetFrameMetrics();
    if (frameMetrics.IsScrollable()) {
      return containerLayer;
    }

    Layer* child = containerLayer->GetFirstChild();
    while (child) {
      queue.AppendElement(child);
      child = child->GetNextSibling();
    }
  }

  return root;
}