Warning: This function is
currently not documented; only the argument list is
available.
Warning: This function is
EXPERIMENTAL. The behaviour of this function, the
name of this function, and anything else documented about this
function may change without notice in a future release of PHP.
Use this function at your own risk.
Returns the shape to be used at the corners of paths (or other vector shapes) when they are stroked.
Return Values
Returns one of the LINEJOIN_ constants or 0 if stroke line join is not set.