internal static void OnVisualChanged(Object sender, DependencyPropertyChangedEventArgs e)
{
Viewport2DVisual3D viewport2DVisual3D = ((Viewport2DVisual3D)sender);
// remove the old parent, add on a new one
Visual oldValue = (Visual)e.OldValue;
Visual newValue = (Visual)e.NewValue;
if (oldValue != newValue)
{
//
// The following code deals with properly setting up the new child to have its inheritance context
// only point towards this Viewport2DVisual3D.
//
// When we add the new visual as a child, if that visual is an FE (which most will be) we expect it to
// clear the inheritance context (IC) since it has a visual parent. In the case of a non-FE they don't
// deal with ICs anyway, so they should have a null IC. The Assert that follows then guards against
// the child not having a null inheritance context.
//
// We then set the target Visual on the internal brush to be this new visual. Since when we created
// the brush we set it to not be an inheritance context, the InheritanceContext should still be null.
//
// We become the IC after returning from this function, since the function that calls this change handler
// will set us as the IC.
//
if (viewport2DVisual3D.CacheMode as BitmapCache != null)
{
viewport2DVisual3D.InternalBitmapCacheBrush.Target = newValue;
Debug.Assert((newValue == null || newValue.InheritanceContext == null),
"Expected BitmapCacheBrush to remove the InheritanceContext on newValue");
}
else
{
// Add ourselves as the parent of the object
viewport2DVisual3D.RemoveVisualChild(oldValue);
viewport2DVisual3D.AddVisualChild(newValue);
Debug.Assert((newValue == null || newValue.InheritanceContext == null),
"Expected AddVisualChild to remove the InheritanceContext on newValue");
// Change the brush's target
viewport2DVisual3D.InternalVisualBrush.Visual = newValue;
// setting the visual brush to use this new child should not invalidate our previous condition
Debug.Assert((newValue == null || newValue.InheritanceContext == null),
"Expected the InternalVisualBrush not to set the InheritanceContext");
}
}
}
internal static void OnCacheModeChanged(Object sender, DependencyPropertyChangedEventArgs e)
{
Viewport2DVisual3D viewport2DVisual3D = ((Viewport2DVisual3D)sender);
BitmapCache oldValue = (CacheMode)e.OldValue as BitmapCache;
BitmapCache newValue = (CacheMode)e.NewValue as BitmapCache;
if (oldValue != newValue)
{
viewport2DVisual3D.InternalBitmapCacheBrush.BitmapCache = newValue;
//
// The BitmapCacheBrush doesn't point directly at the Visual like the VisualBrush does,
// since BitmapCacheBrush ignores most properties on a Visual by design. In order for
// those properties to be respected to match the internal VisualBrush's behavior, we insert
// a dummy Visual node between the V2DV3D and its 2D Visual. We then target the dummy
// node with the brush instead.
//
if (oldValue == null)
{
//
// If we are swapping from using the VisualBrush to using the BitmapCacheBrush...
//
// Remove the visual child from the V2DV3D and add the dummy child.
viewport2DVisual3D.RemoveVisualChild(viewport2DVisual3D.Visual);
viewport2DVisual3D.AddVisualChild(viewport2DVisual3D.InternalBitmapCacheBrush.InternalTarget);
Debug.Assert((viewport2DVisual3D.InternalBitmapCacheBrush.InternalTarget == null ||
viewport2DVisual3D.InternalBitmapCacheBrush.InternalTarget.InheritanceContext == null),
"Expected AddVisualChild to remove the InheritanceContext on InternalTarget");
// Swap the brush pointing to the visual. The cache brush will re-parent the visual to the dummy.
viewport2DVisual3D.InternalVisualBrush.Visual = null;
viewport2DVisual3D.InternalBitmapCacheBrush.Target = viewport2DVisual3D.Visual;
// setting the cache brush to use this new child should not invalidate our previous condition
Debug.Assert((viewport2DVisual3D.InternalBitmapCacheBrush.InternalTarget == null ||
viewport2DVisual3D.InternalBitmapCacheBrush.InternalTarget.InheritanceContext == null),
"Expected the InternalBitmapCacheBrush not to set the InheritanceContext");
}
if (newValue == null)
{
//
// If we are swapping from using the BitmapCacheBrush to using the VisualBrush...
//
// Swap the brush pointing to the visual. The cache brush will remove the dummy as the parent
// of the visual.
viewport2DVisual3D.InternalBitmapCacheBrush.Target = null;
viewport2DVisual3D.InternalVisualBrush.Visual = viewport2DVisual3D.Visual;
// Remove the dummy child and re-add the visual as the V2DV3D's child.
viewport2DVisual3D.RemoveVisualChild(viewport2DVisual3D.InternalBitmapCacheBrush.InternalTarget);
viewport2DVisual3D.AddVisualChild(viewport2DVisual3D.Visual);
Debug.Assert((viewport2DVisual3D.Visual == null || viewport2DVisual3D.Visual.InheritanceContext == null),
"Expected AddVisualChild to remove the InheritanceContext on Visual");
}
// If we changed from using one brush to the other we need to regenerate the Material.
if (oldValue == null || newValue == null)
{
viewport2DVisual3D.GenerateMaterial();
}
}
}