C++ HTMLVideoElement::GetImageContainer方法代码示例

/* static */ already_AddRefed<ImageBitmap>
ImageBitmap::CreateInternal(nsIGlobalObject* aGlobal, HTMLVideoElement& aVideoEl,
                            const Maybe<IntRect>& aCropRect, ErrorResult& aRv)
{
  // Check network state.
  if (aVideoEl.NetworkState() == HTMLMediaElement::NETWORK_EMPTY) {
    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
    return nullptr;
  }

  // Check ready state.
  // Cannot be HTMLMediaElement::HAVE_NOTHING or HTMLMediaElement::HAVE_METADATA.
  if (aVideoEl.ReadyState() <= HTMLMediaElement::HAVE_METADATA) {
    aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
    return nullptr;
  }

  // Check security.
  nsCOMPtr<nsIPrincipal> principal = aVideoEl.GetCurrentPrincipal();
  bool CORSUsed = aVideoEl.GetCORSMode() != CORS_NONE;
  if (!CheckSecurityForHTMLElements(false, CORSUsed, principal)) {
    aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
    return nullptr;
  }

  // Create ImageBitmap.
  ImageContainer *container = aVideoEl.GetImageContainer();

  if (!container) {
    aRv.Throw(NS_ERROR_NOT_AVAILABLE);
    return nullptr;
  }

  AutoLockImage lockImage(container);
  layers::Image* data = lockImage.GetImage();
  RefPtr<ImageBitmap> ret = new ImageBitmap(aGlobal, data);

  // Set the picture rectangle.
  if (ret && aCropRect.isSome()) {
    ret->SetPictureRect(aCropRect.ref(), aRv);
  }

  return ret.forget();
}

already_AddRefed<Layer>
nsVideoFrame::BuildLayer(nsDisplayListBuilder* aBuilder,
                         LayerManager* aManager,
                         nsDisplayItem* aItem,
                         const ContainerLayerParameters& aContainerParameters)
{
  nsRect area = GetContentRect() - GetPosition() + aItem->ToReferenceFrame();
  HTMLVideoElement* element = static_cast<HTMLVideoElement*>(GetContent());
  nsIntSize videoSize;
  if (NS_FAILED(element->GetVideoSize(&videoSize)) || area.IsEmpty()) {
    return nullptr;
  }

  nsRefPtr<ImageContainer> container = element->GetImageContainer();
  if (!container)
    return nullptr;
  
  // Retrieve the size of the decoded video frame, before being scaled
  // by pixel aspect ratio.
  mozilla::gfx::IntSize frameSize = container->GetCurrentSize();
  if (frameSize.width == 0 || frameSize.height == 0) {
    // No image, or zero-sized image. No point creating a layer.
    return nullptr;
  }

  // Compute the rectangle in which to paint the video. We need to use
  // the largest rectangle that fills our content-box and has the
  // correct aspect ratio.
  nsPresContext* presContext = PresContext();
  gfxRect r = gfxRect(presContext->AppUnitsToGfxUnits(area.x),
                      presContext->AppUnitsToGfxUnits(area.y),
                      presContext->AppUnitsToGfxUnits(area.width),
                      presContext->AppUnitsToGfxUnits(area.height));
  r = CorrectForAspectRatio(r, videoSize);
  r.Round();
  if (r.IsEmpty()) {
    return nullptr;
  }
  IntSize scaleHint(static_cast<int32_t>(r.Width()),
                    static_cast<int32_t>(r.Height()));
  container->SetScaleHint(scaleHint);

  nsRefPtr<ImageLayer> layer = static_cast<ImageLayer*>
    (aManager->GetLayerBuilder()->GetLeafLayerFor(aBuilder, aItem));
  if (!layer) {
    layer = aManager->CreateImageLayer();
    if (!layer)
      return nullptr;
  }

  layer->SetContainer(container);
  layer->SetFilter(nsLayoutUtils::GetGraphicsFilterForFrame(this));
  layer->SetContentFlags(Layer::CONTENT_OPAQUE);
  // Set a transform on the layer to draw the video in the right place
  gfx::Matrix transform;
  gfxPoint p = r.TopLeft() + aContainerParameters.mOffset;
  transform.Translate(p.x, p.y);
  transform.Scale(r.Width()/frameSize.width, r.Height()/frameSize.height);
  layer->SetBaseTransform(gfx::Matrix4x4::From2D(transform));
  layer->SetVisibleRegion(nsIntRect(0, 0, frameSize.width, frameSize.height));
  nsRefPtr<Layer> result = layer.forget();
  return result.forget();
}

already_AddRefed<Layer>
nsVideoFrame::BuildLayer(nsDisplayListBuilder* aBuilder,
                         LayerManager* aManager,
                         nsDisplayItem* aItem,
                         const ContainerLayerParameters& aContainerParameters)
{
  nsRect area = GetContentRectRelativeToSelf() + aItem->ToReferenceFrame();
  HTMLVideoElement* element = static_cast<HTMLVideoElement*>(GetContent());

  nsIntSize videoSizeInPx;
  if (NS_FAILED(element->GetVideoSize(&videoSizeInPx)) ||
      area.IsEmpty()) {
    return nullptr;
  }

  RefPtr<ImageContainer> container = element->GetImageContainer();
  if (!container)
    return nullptr;

  // Retrieve the size of the decoded video frame, before being scaled
  // by pixel aspect ratio.
  mozilla::gfx::IntSize frameSize = container->GetCurrentSize();
  if (frameSize.width == 0 || frameSize.height == 0) {
    // No image, or zero-sized image. No point creating a layer.
    return nullptr;
  }

  // Convert video size from pixel units into app units, to get an aspect-ratio
  // (which has to be represented as a nsSize) and an IntrinsicSize that we
  // can pass to ComputeObjectRenderRect.
  nsSize aspectRatio(nsPresContext::CSSPixelsToAppUnits(videoSizeInPx.width),
                     nsPresContext::CSSPixelsToAppUnits(videoSizeInPx.height));
  IntrinsicSize intrinsicSize;
  intrinsicSize.width.SetCoordValue(aspectRatio.width);
  intrinsicSize.height.SetCoordValue(aspectRatio.height);

  nsRect dest = nsLayoutUtils::ComputeObjectDestRect(area,
                                                     intrinsicSize,
                                                     aspectRatio,
                                                     StylePosition());

  gfxRect destGFXRect = PresContext()->AppUnitsToGfxUnits(dest);
  destGFXRect.Round();
  if (destGFXRect.IsEmpty()) {
    return nullptr;
  }

  VideoInfo::Rotation rotationDeg = element->RotationDegrees();
  IntSize scaleHint(static_cast<int32_t>(destGFXRect.Width()),
                    static_cast<int32_t>(destGFXRect.Height()));
  // scaleHint is set regardless of rotation, so swap w/h if needed.
  SwapScaleWidthHeightForRotation(scaleHint, rotationDeg);
  container->SetScaleHint(scaleHint);

  RefPtr<ImageLayer> layer = static_cast<ImageLayer*>
    (aManager->GetLayerBuilder()->GetLeafLayerFor(aBuilder, aItem));
  if (!layer) {
    layer = aManager->CreateImageLayer();
    if (!layer)
      return nullptr;
  }

  layer->SetContainer(container);
  layer->SetSamplingFilter(nsLayoutUtils::GetSamplingFilterForFrame(this));
  // Set a transform on the layer to draw the video in the right place
  gfxPoint p = destGFXRect.TopLeft() + aContainerParameters.mOffset;

  Matrix preTransform = ComputeRotationMatrix(destGFXRect.Width(),
                                              destGFXRect.Height(),
                                              rotationDeg);

  Matrix transform = preTransform * Matrix::Translation(p.x, p.y);

  layer->SetBaseTransform(gfx::Matrix4x4::From2D(transform));
  layer->SetScaleToSize(scaleHint, ScaleMode::STRETCH);
  RefPtr<Layer> result = layer.forget();
  return result.forget();
}