public static RequestedTransform GetTransform <RequestedTransform>(this UIElement element, bool create) where RequestedTransform : Transform, new()
{
TransformCreationMode mode = TransformCreationMode.None;
if (create)
{
mode = TransformCreationMode.Create | TransformCreationMode.AddToGroup;
}
return(element.GetTransform <RequestedTransform>(mode));
}
/// <summary>
/// Returns a render transform of the specified type from the element, creating it if necessary
/// </summary>
/// <typeparam name="TRequestedTransform">The type of transform (Rotate, Translate, etc)</typeparam>
/// <param name="element">The element to check</param>
/// <param name="mode">The mode to use for creating transforms, if not found</param>
/// <returns>The specified transform, or null if not found and not created</returns>
public static TRequestedTransform GetTransform <TRequestedTransform>(this UIElement element, TransformCreationMode mode) where TRequestedTransform : Transform, new()
{
Transform originalTransform = element.RenderTransform;
TRequestedTransform requestedTransform = null;
MatrixTransform matrixTransform = null;
TransformGroup transformGroup = null;
// Current transform is null -- create if necessary and return
if (originalTransform == null)
{
if ((mode & TransformCreationMode.Create) == TransformCreationMode.Create)
{
requestedTransform = new TRequestedTransform();
element.RenderTransform = requestedTransform;
return(requestedTransform);
}
return(null);
}
// Transform is exactly what we want -- return it
requestedTransform = originalTransform as TRequestedTransform;
if (requestedTransform != null)
{
return(requestedTransform);
}
// The existing transform is matrix transform - overwrite if necessary and return
matrixTransform = originalTransform as MatrixTransform;
if (matrixTransform != null)
{
if (matrixTransform.Matrix.IsIdentity &&
(mode & TransformCreationMode.Create) == TransformCreationMode.Create &&
(mode & TransformCreationMode.IgnoreIdentityMatrix) == TransformCreationMode.IgnoreIdentityMatrix)
{
requestedTransform = new TRequestedTransform();
element.RenderTransform = requestedTransform;
return(requestedTransform);
}
return(null);
}
// Transform is actually a group -- check for the requested type
transformGroup = originalTransform as TransformGroup;
if (transformGroup != null)
{
foreach (Transform child in transformGroup.Children)
{
// Child is the right type -- return it
if (child is TRequestedTransform)
{
return(child as TRequestedTransform);
}
}
// Right type was not found, but we are OK to add it
if ((mode & TransformCreationMode.AddToGroup) == TransformCreationMode.AddToGroup)
{
requestedTransform = new TRequestedTransform();
transformGroup.Children.Add(requestedTransform);
return(requestedTransform);
}
return(null);
}
// Current ransform is not a group and is not what we want;
// create a new group containing the existing transform and the new one
if ((mode & TransformCreationMode.CombineIntoGroup) == TransformCreationMode.CombineIntoGroup)
{
transformGroup = new TransformGroup();
transformGroup.Children.Add(originalTransform);
transformGroup.Children.Add(requestedTransform);
element.RenderTransform = transformGroup;
return(requestedTransform);
}
Debug.Assert(false, "Shouldn't get here");
return(null);
}
/// <summary>Returns a render transform of the specified type from the element, creating it if necessary. </summary>
/// <typeparam name="TRequestedTransform">The type of transform (Rotate, Translate, etc)</typeparam>
/// <param name="element">The element to check</param>
/// <param name="mode">The mode to use for creating transforms, if not found</param>
/// <returns>The specified transform, or null if not found and not created</returns>
public static TRequestedTransform GetTransform <TRequestedTransform>(this UIElement element, TransformCreationMode mode)
where TRequestedTransform : Transform, new()
{
Transform originalTransform = element.RenderTransform;
if (originalTransform == null)
{
if ((mode & TransformCreationMode.Create) == TransformCreationMode.Create)
{
element.RenderTransform = new TRequestedTransform();
return((TRequestedTransform)element.RenderTransform);
}
return(null);
}
var requestedTransform = originalTransform as TRequestedTransform;
if (requestedTransform != null)
{
return(requestedTransform);
}
var matrixTransform = originalTransform as MatrixTransform;
if (matrixTransform != null)
{
if (matrixTransform.Matrix.IsIdentity &&
(mode & TransformCreationMode.Create) == TransformCreationMode.Create &&
(mode & TransformCreationMode.IgnoreIdentityMatrix) == TransformCreationMode.IgnoreIdentityMatrix)
{
requestedTransform = new TRequestedTransform();
element.RenderTransform = requestedTransform;
return(requestedTransform);
}
return(null);
}
var transformGroup = originalTransform as TransformGroup;
if (transformGroup != null)
{
foreach (Transform child in transformGroup.Children)
{
if (child is TRequestedTransform)
{
return(child as TRequestedTransform);
}
}
if ((mode & TransformCreationMode.AddToGroup) == TransformCreationMode.AddToGroup)
{
requestedTransform = new TRequestedTransform();
transformGroup.Children.Add(requestedTransform);
return(requestedTransform);
}
return(null);
}
if ((mode & TransformCreationMode.CombineIntoGroup) == TransformCreationMode.CombineIntoGroup)
{
requestedTransform = new TRequestedTransform();
transformGroup = new TransformGroup();
transformGroup.Children.Add(originalTransform);
transformGroup.Children.Add(requestedTransform);
element.RenderTransform = transformGroup;
return(requestedTransform);
}
return(null);
}
