Reason behind location of 0,0,0?

[waveletlet]

I know this project is discontinued, I'm working through it to try to figure out graphics in gomobile and thinking about writing a UI package based on it. From a design standpoint, was there any particular reason you decided to make the lower left corner 0,0,0, rather than the upper left? It makes it a bit confusing when translating the Y coordinate from a touch.Event

[dskinner]

I realize this is two years later, but as I recall the material design guidelines called for it. Eventually, touch events would have been replaced with something that sits in front of them (and in fact, I wrote such over in my dskinner/x package some time ago). For the end developer though, material design defined the orientation as such and I was simply implementing it as it was stated.