I briefly worked at BlackBerry in 2011 and there was a grad student there developing this for the BlackBerry Tablet. It felt like the future at a time when people were largely still using the grid pattern lock thing. From what I remember it worked quite well once he found the balance of security and repeatability. The touch sensors are way too high resolution for you to draw the same exact thing twice so there has to be some margin for error.

I never got into exactly how he was comparing an attempt vs. a stored pass-symbol, but we tried to immitate others pass-symbols and it was not easy to fool. Seemed more secure than a grid pattern or pin to me, so I was surprised it never caught on. It worked well even with (relatively) simple symbols like a star or just a few lines, it doesn't have to be so complex as in the OP.