/// <summary>
/// The returned matrix can be used to transform coordinates from this Visual to
/// the specified Visual.
/// Returns null if no such transform exists due to a non-invertible Transform.
/// </summary>
/// <exception cref="ArgumentNullException">If visual is null.</exception>
/// <exception cref="InvalidOperationException">If the Visuals are not connected.</exception>
public GeneralTransform TransformToVisual(Visual visual)
{
DependencyObject ancestor = FindCommonVisualAncestor(visual);
Visual ancestorAsVisual = ancestor as Visual;
if (ancestorAsVisual == null)
{
throw new System.InvalidOperationException(SR.Get(SRID.Visual_NoCommonAncestor));
}
GeneralTransform g0;
Matrix m0;
bool isSimple0 = this.TrySimpleTransformToAncestor(ancestorAsVisual,
false,
out g0,
out m0);
GeneralTransform g1;
Matrix m1;
bool isSimple1 = visual.TrySimpleTransformToAncestor(ancestorAsVisual,
true,
out g1,
out m1);
// combine the transforms
// if both transforms are simple Matrix transforms, just multiply them and
// return the result.
if (isSimple0 && isSimple1)
{
MatrixUtil.MultiplyMatrix(ref m0, ref m1);
MatrixTransform m = new MatrixTransform(m0);
m.Freeze();
return m;
}
// Handle the case where 0 is simple and 1 is complex.
if (isSimple0)
{
g0 = new MatrixTransform(m0);
g0.Freeze();
}
else if (isSimple1)
{
g1 = new MatrixTransform(m1);
g1.Freeze();
}
// If inverse was requested, TrySimpleTransformToAncestor can return null
// add the transform only if it is not null
if (g1 != null)
{
GeneralTransformGroup group = new GeneralTransformGroup();
group.Children.Add(g0);
group.Children.Add(g1);
group.Freeze();
return group;
}
return g0;
}