#  Interactive Scribbling
#
#  Use the left mouse button to draw, the right button to erase.

link graphics

procedure main()
   local x, y

   WOpen("size=400,300") | stop("*** cannot open window")

   repeat {
      case Event() of {  
         &lpress: {
            DrawPoint(&x, &y)
            x := &x
            y := &y
            }
         &ldrag: {
            DrawLine(x, y, &x, &y)
            x := &x
            y := &y
            }
         &rpress | &rdrag: {
            EraseArea(&x - 2, &y - 2, 5, 5)
            }
         "q": exit()
         }
      }

end