C++ Matrix4x4::ScalePost方法代码示例

bool
LayerTransactionParent::RecvGetAnimationTransform(PLayerParent* aParent,
                                                  MaybeTransform* aTransform)
{
  if (mDestroyed || !layer_manager() || layer_manager()->IsDestroyed()) {
    return false;
  }

  Layer* layer = cast(aParent)->AsLayer();
  if (!layer) {
    return false;
  }

  // This method is specific to transforms applied by animation.
  // This is because this method uses the information stored with an animation
  // such as the origin of the reference frame corresponding to the layer, to
  // recover the untranslated transform from the shadow transform. For
  // transforms that are not set by animation we don't have this information
  // available.
  if (!layer->AsLayerComposite()->GetShadowTransformSetByAnimation()) {
    *aTransform = mozilla::void_t();
    return true;
  }

  // The following code recovers the untranslated transform
  // from the shadow transform by undoing the translations in
  // AsyncCompositionManager::SampleValue.

  Matrix4x4 transform = layer->AsLayerComposite()->GetShadowTransform();
  if (ContainerLayer* c = layer->AsContainerLayer()) {
    // Undo the scale transform applied by AsyncCompositionManager::SampleValue
    transform.ScalePost(1.0f/c->GetInheritedXScale(),
                        1.0f/c->GetInheritedYScale(),
                        1.0f);
  }
  float scale = 1;
  gfxPoint3D scaledOrigin;
  gfxPoint3D transformOrigin;
  for (uint32_t i=0; i < layer->GetAnimations().Length(); i++) {
    if (layer->GetAnimations()[i].data().type() == AnimationData::TTransformData) {
      const TransformData& data = layer->GetAnimations()[i].data().get_TransformData();
      scale = data.appUnitsPerDevPixel();
      scaledOrigin =
        gfxPoint3D(NS_round(NSAppUnitsToFloatPixels(data.origin().x, scale)),
                   NS_round(NSAppUnitsToFloatPixels(data.origin().y, scale)),
                   0.0f);
      double cssPerDev =
        double(nsDeviceContext::AppUnitsPerCSSPixel()) / double(scale);
      transformOrigin = data.transformOrigin() * cssPerDev;
      break;
    }
  }

  // Undo the translation to the origin of the reference frame applied by
  // AsyncCompositionManager::SampleValue
  transform.Translate(-scaledOrigin.x, -scaledOrigin.y, -scaledOrigin.z);

  // Undo the rebasing applied by
  // nsDisplayTransform::GetResultingTransformMatrixInternal
  gfxPoint3D basis = -scaledOrigin - transformOrigin;
  transform.ChangeBasis(basis.x, basis.y, basis.z);

  // Convert to CSS pixels (this undoes the operations performed by
  // nsStyleTransformMatrix::ProcessTranslatePart which is called from
  // nsDisplayTransform::GetResultingTransformMatrix)
  double devPerCss =
    double(scale) / double(nsDeviceContext::AppUnitsPerCSSPixel());
  transform._41 *= devPerCss;
  transform._42 *= devPerCss;
  transform._43 *= devPerCss;

  *aTransform = transform;
  return true;
}

void
AsyncCompositionManager::TransformScrollableLayer(Layer* aLayer)
{
  LayerComposite* layerComposite = aLayer->AsLayerComposite();

  const FrameMetrics& metrics = aLayer->GetFrameMetrics();
  // We must apply the resolution scale before a pan/zoom transform, so we call
  // GetTransform here.
  Matrix4x4 oldTransform = aLayer->GetTransform();

  CSSToLayerScale geckoZoom = metrics.LayersPixelsPerCSSPixel();

  LayerIntPoint scrollOffsetLayerPixels = RoundedToInt(metrics.GetScrollOffset() * geckoZoom);

  if (mIsFirstPaint) {
    mContentRect = metrics.mScrollableRect;
    SetFirstPaintViewport(scrollOffsetLayerPixels,
                          geckoZoom,
                          mContentRect);
    mIsFirstPaint = false;
  } else if (!metrics.mScrollableRect.IsEqualEdges(mContentRect)) {
    mContentRect = metrics.mScrollableRect;
    SetPageRect(mContentRect);
  }

  // We synchronise the viewport information with Java after sending the above
  // notifications, so that Java can take these into account in its response.
  // Calculate the absolute display port to send to Java
  LayerIntRect displayPort = RoundedToInt(
    (metrics.mCriticalDisplayPort.IsEmpty()
      ? metrics.mDisplayPort
      : metrics.mCriticalDisplayPort
    ) * geckoZoom);
  displayPort += scrollOffsetLayerPixels;

  LayerMargin fixedLayerMargins(0, 0, 0, 0);
  ScreenPoint offset(0, 0);

  // Ideally we would initialize userZoom to AsyncPanZoomController::CalculateResolution(metrics)
  // but this causes a reftest-ipc test to fail (see bug 883646 comment 27). The reason for this
  // appears to be that metrics.mZoom is poorly initialized in some scenarios. In these scenarios,
  // however, we can assume there is no async zooming in progress and so the following statement
  // works fine.
  CSSToScreenScale userZoom(metrics.mDevPixelsPerCSSPixel * metrics.mCumulativeResolution * LayerToScreenScale(1));
  ScreenPoint userScroll = metrics.GetScrollOffset() * userZoom;
  SyncViewportInfo(displayPort, geckoZoom, mLayersUpdated,
                   userScroll, userZoom, fixedLayerMargins,
                   offset);
  mLayersUpdated = false;

  // Apply the render offset
  mLayerManager->GetCompositor()->SetScreenRenderOffset(offset);

  // Handle transformations for asynchronous panning and zooming. We determine the
  // zoom used by Gecko from the transformation set on the root layer, and we
  // determine the scroll offset used by Gecko from the frame metrics of the
  // primary scrollable layer. We compare this to the user zoom and scroll
  // offset in the view transform we obtained from Java in order to compute the
  // transformation we need to apply.
  ScreenPoint geckoScroll(0, 0);
  if (metrics.IsScrollable()) {
    geckoScroll = metrics.GetScrollOffset() * userZoom;
  }
  ParentLayerToScreenScale scale = userZoom
                                  / metrics.mDevPixelsPerCSSPixel
                                  / metrics.GetParentResolution();
  ScreenPoint translation = userScroll - geckoScroll;
  Matrix4x4 treeTransform = ViewTransform(scale, -translation);

  // The transform already takes the resolution scale into account.  Since we
  // will apply the resolution scale again when computing the effective
  // transform, we must apply the inverse resolution scale here.
  Matrix4x4 computedTransform = oldTransform * treeTransform;
  if (ContainerLayer* container = aLayer->AsContainerLayer()) {
    computedTransform.Scale(1.0f/container->GetPreXScale(),
                            1.0f/container->GetPreYScale(),
                            1);
  }
  computedTransform.ScalePost(1.0f/aLayer->GetPostXScale(),
                              1.0f/aLayer->GetPostYScale(),
                              1);
  layerComposite->SetShadowTransform(computedTransform);
  NS_ASSERTION(!layerComposite->GetShadowTransformSetByAnimation(),
               "overwriting animated transform!");

  // Apply resolution scaling to the old transform - the layer tree as it is
  // doesn't have the necessary transform to display correctly.
  oldTransform.Scale(metrics.mResolution.scale, metrics.mResolution.scale, 1);

  // Make sure that overscroll and under-zoom are represented in the old
  // transform so that fixed position content moves and scales accordingly.
  // These calculations will effectively scale and offset fixed position layers
  // in screen space when the compensatory transform is performed in
  // AlignFixedAndStickyLayers.
  ScreenRect contentScreenRect = mContentRect * userZoom;
  gfxPoint3D overscrollTranslation;
  if (userScroll.x < contentScreenRect.x) {
    overscrollTranslation.x = contentScreenRect.x - userScroll.x;
  } else if (userScroll.x + metrics.mCompositionBounds.width > contentScreenRect.XMost()) {
    overscrollTranslation.x = contentScreenRect.XMost() -
//.........这里部分代码省略.........