[comp.sys.mac.programmer] Quickdraw scaling question.

mfi@beach.cis.ufl.edu (Mark Interrante) (03/05/89)

I have a question about quickdraw graphics, I am trying to scale a
drawing smaller and larger in lisp.  The following code draws an oval and draws
it at half its original size.  When I modify the code so that the rectangle
is [0,0] by [200,200] instead of [0,0 by [50,50] I get no image on the 
window.  Any rectangle larger than the original produces that same result.
Is this an incorrect method for enlarging a drawing, or might there be
some problem in lisps quickdraw access routines? Thanks. 

-------
(rlet ((temp-rect :rect              ;temporarily allocate a rectangle
                  :top 0          ;
                  :left 0        ;
                  :bottom 100    ;
                  :right 100)
       (t-rect :rect              ;temporarily allocate a rectangle
                  :top 0          ;
                  :left 0        ;
                  :bottom 50    ;
                  :right 50))    ;

  
  (ask window (start-picture temp-rect))  ;start a drawing
  (ask window (paint-oval temp-rect))     ;draw something
  (setq image (ask gw (get-picture)))    ;finish drawing
  (ask window (draw-picture image t-rect)))  ;display drawing


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Mark Interrante   		Software Engineering Research Center
mfi@beach.cis.ufl.edu		CIS Department, University of Florida 32611
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