I always wondered how Processing handles transformations so that a translate, for example, doesn't get repeated each time the function is called (each frame). Every time I try to set up my own translation I have to use translate(mouseX-pmouseX, mouseY-pmouseY) to get the same effect of Processing's translate(mouseX, mouseY). The only other way I've been able to do it is the following:

1.   void move(float x, float y) {
2.     if(x != tx || y != ty) {
3.       AffineTransform ng = AffineTransform.
4.         getTranslateInstance((double)-tx,(double)-ty);
5.       transform(ng);
6.       AffineTransform mv = AffineTransform.
7.         getTranslateInstance((double)x, (double)y);
8.       transform(mv);
9.       tx = x;
10.       ty = y;
11.     }
12.   }

I'm pretty sure that is not how Processing does it. Does anyone know how that stuff works?