On Mon, Jun 17, 2019 at 7:31 PM Tony V E <tvaneerd@gmail.com> wrote:
I can only imagine that mouse/touch input needs to be in the same coordinate system as the drawing. 

It almost never is at the device level. Although the higher level APIs users are accustomed to do commonly transform to "drawing" coordinates.

-- Rene Rivera
-- Grafik - Don't Assume Anything
-- Robot Dreams - http://robot-dreams.net