/// <summary>
/// Transform a Rect3D to a Rect. If this transformation cannot be completed Rect.Empty is returned.
/// </summary>
/// <param name="rect3D">Input 3D bounding box</param>
/// <returns>The 2D bounding box of the projection of these points</returns>
public Rect TransformBounds(Rect3D rect3D)
{
if (_transformBetween2D != null)
{
return(_transformBetween2D.TransformBounds(MILUtilities.ProjectBounds(ref _projectionTransform, ref rect3D)));
}
else
{
return(Rect.Empty);
}
}
internal override Rect CalculateSubgraphBoundsInnerSpace(bool renderBounds)
{
Camera camera = Camera;
if (camera == null)
{
return(Rect.Empty);
}
//
// Cache the 3D bounding box for future use. Here we are relying on
// the fact that this method is called by PrecomputeContent(),
// which is called prior to all usages of _bboxChildrenSubgraph3D.
//
_bboxChildrenSubgraph3D = ComputeSubgraphBounds3D();
if (_bboxChildrenSubgraph3D.IsEmpty)
{
// Attempting to project empty bounds will result in NaNs which
// which will ruin descendant bounds for the 2D tree. We handle
// this explicitly and early exit with the correct answer.
return(Rect.Empty);
}
Rect viewport = Viewport;
// Common Case: Viewport3DVisual in a collasped UIElement.
if (viewport.IsEmpty)
{
// Creating a 3D homogenous space to 2D viewport space transform
// with an empty rectangle will result in NaNs which ruin the
// descendant bounds for the 2D tree. We handle this explicitly
// and early exit with the correct answer.
//
// (See also Windows OS Bugs #1637618)
return(Rect.Empty);
}
double aspectRatio = M3DUtil.GetAspectRatio(viewport.Size);
Matrix3D viewProjMatrix = camera.GetViewMatrix() * camera.GetProjectionMatrix(aspectRatio);
Rect projectedBounds2D = MILUtilities.ProjectBounds(ref viewProjMatrix, ref _bboxChildrenSubgraph3D);
Matrix homoToLocal = M3DUtil.GetHomogeneousToViewportTransform(viewport);
MatrixUtil.TransformRect(ref projectedBounds2D, ref homoToLocal);
return(projectedBounds2D);
}
