myArc()
does not belong to PGraphics. You can do:
void myEllipse(PGraphics pg, int x, int y){
//Assuming begin draw has already been called
pg.ellipse(x,y,5,5);
}
and you will use it like this:
circles.beginDraw();
circles.noStroke()
circles.fill(col);
myEllipse(circles,mouseX, mouseY);
circles.endDraw();
The small issue is that in this example I am not managing begin/endDraw. It is possible but you need to have a proper design aka. very well thought.
Kf