5.102 Stroke

          [PenMode:=1, {NotXor mode}  
           NewGraph("object1", "Cercle(a,1)"),  
           PenMode:=0, {normal mode}  
           ReDraw(), {we show}  

we create the macro MouseMove with the command: if drawing then a:=%1 {we move the center}, Move(object1) fi,

then the macro LButtonUp with the command: if drawing then Stroke(object1), drawing:=0 fi.

The macro ClicG creates the object1 in NotXor mode, update the graphical display and switch to the "drawing" mode. The macro MouseMove places the center a at the mouse place, then moves the object1. When the left button is released, we draw the object1 in normal mode and quit the "drawing" mode.