You mean something like this?
Global window=CreateWindow("Canvas Painter",10,10,400,400,0) Global canvas=CreateCanvas(2,2,400,400,window) SetBuffer CanvasBuffer(canvas) Line 20,20,20,300 ;vertical line Color 210,250,250 Oval 50,50,100,200,1 FlipCanvas canvas Repeat WaitEvent() Until EventID()=$803 End