Generate a random black and white   320x240   image continuously,
showing FPS (frames per second).



A sample image
 


link printf
 
procedure main() 
   &window := open("B&W noise 320x240","g","size=320,240","bg=white","fg=black") | 
              stop("Open window failed ")
   runtime := 10 # seconds to run
   sec := &now
   frames := 0
   until (&now - sec) >= runtime do {
      s := "320,#"
      every 1 to 240 & 1 to 320/4 do s ||:= ?"0123456789ABCDEF" 
      DrawImage(0,0,s)
      frames +:= 1
      }
   sec := &now - sec 
   printf("frames=%d, elapsed time=%r, fps=%r\n",frames,sec, frames/real(sec))
   Event()   # wait for any window event
   close(&window)
end