求助！！！

lovelilin

请问各位大侠下面两个是什么意思？ " viewctr " 和" viewsize " 再就是下面这段程式中间一段有点不不解: (defun C:rf()
(setvar "cmdecho" 0)
(setq viewctr (getvar "viewctr"))
(setq viewsize (getvar "viewsize"))
(setq corner1 (list (+ (/ viewsize 1.2) )(car viewctr)
(+ (/ viewsize 2) (cadr viewctr) )))
(setq corner2 (list (- (car viewctr) (/ viewsize 1.2)) (- (cadr Viewctr) (/ viewsize 2) )))
(ssget "C" corner1 corner2)
(command "erase" "P" "")
(command "undo" "")
(princ))

meflying

帮助文件中有介绍