getpoint's output vs list

[Anonymous]

Hi,

Is getpoint's output equal to '(1.0 2.0)?

Here's what i'm trying to do:

 (setq pt3 '((- x1 pt1x) (- y1 pt1y)))
 (setq pt4 '((+ x1 pt2x) (+ y1 pt2y)))
 (command "_ellipse" pt3 pt4 axe2)

[marko_ribar]

Apostrophe in lisp syntax is treated literally, so this won't work :

 (setq pt3 '((- x1 pt1x) (- y1 pt1y)))
 (setq pt4 '((+ x1 pt2x) (+ y1 pt2y)))

Instead you should force ACAD to evaluate expressions using (list) function :

Now if x1, pt1x, y1, pt1y, pt2x, pt2y are reals stored in those variables, this should work :

 (setq pt3 (list (- x1 pt1x) (- y1 pt1y)))
 (setq pt4 (list (+ x1 pt2x) (+ y1 pt2y)))

HTH., M.R.

[Ranjit_Singh]

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@Anonymous wrote:

Hi,

 Is getpoint's output equal to '(1.0 2.0)?

 ..........

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Call the getpoint function at AutoCAD command prompt and pick a point. You will see that it consists of x, y and z coordinates. If the elevation of resulting ellipse does not matter then ignore z co-ordinate and the ellipse will be at default elevation. As pointed out in post 2, use list instead of quote.

[dbroad]

Another approach.  For mapcar, the shortest list governs the result.

(setq p1 '(1.0 2.0) ;;assumed half major axis offsets from center
      p2 (getpoint "\nPick point: ") ;;assumed center point
      )
(setq p3 (mapcar '- p2 p1)
      p4 (mapcar '+ p2 p1)
      )
(command "._ellipse" p3 p4 pause)