Declares the start of a path drawing list which is terminated by a matching
DrawPathFinish() command. All other DrawPath commands must be enclosed
between a and a DrawPathFinish() command. This is because path drawing
commands are subordinate commands and they do not function by themselves.
Between $draw->pathStart() and $draw->pathFinish() you would need to start with $draw->pathMoveToAbsolute(x, y) to initialise the position. All the subsequent calls to "path functions" (including absolute ones) will continue the path.
I would expect pathStart to accept the starting coordinates, and it took me a while to realise that there you need to initialise with a different function.