[编程交流] 计算精确长度

(defun C:OffsetJoinCopy ( / offsetobject )
(setvar "cmdecho" 0)
(command "UNDO" "BEGIN")
(if (= offsetdepthvalue nil)(setq offsetdepthvalue 0.0))
(if (= offsetwidthvalue nil)(setq offsetwidthvalue 0.0))
(setq newoffsetdepthvalue (getreal (strcat "Specify offset depth <" (rtos offsetdepthvalue 2) ">: ")))
(cond
        ((= newoffsetdepthvalue nil)
                (setq offsetdepthvalue offsetdepthvalue)
        )
        (t
                (setq offsetdepthvalue newoffsetdepthvalue)
        )
)
(setq newoffsetwidthvalue (getreal (strcat "Specify offset width <" (rtos offsetwidthvalue 2) ">: ")))
(cond
        ((= newoffsetwidthvalue nil)
                (setq offsetdepthvalue offsetwidthvalue)
        )
        (t
                (setq offsetwidthvalue newoffsetwidthvalue)
        )
)
(setq offsetobject (entsel "\nSelect object to offset: "))
(cond
        ((and (/= offsetdepthvalue 0)(/= offsetwidthvalue 0)(/= offsetobject nil))
                (setvar "peditaccept" 1)
                (command "_COPY" offsetobject "" "" "")
                (setq topline (entlast))
                (setq currentlength (vlax-curve-getdistatparam (entlast) (vlax-curve-getendparam (entlast))))
                [color="red"](setq newlength (+ currentlength (* 2 offsetwidthvalue)))[/color]
                (setq extendlength (/ (- newlength currentlength) 2))
                (setq StrtPnt (vlax-curve-getStartPoint (entlast)))
                (setq EnfPoint (vlax-curve-getEndPoint (entlast)))
                (vl-cmdf "_.lengthen" "Delta" extendlength StrtPnt EnfPoint "")
                (command "_COPY" (entlast) "" "" "")
                (command "_MOVE" (entlast) "" "0,0" (strcat "0,-" (rtos offsetdepthvalue)))
                (setq xy1 (strcat (rtos (car (cdr (assoc 10 (entget (entlast)))))) "," (rtos (car (cdr (cdr (assoc 10 (entget (entlast)))))))))
                (setq xy2 (strcat (rtos (car (cdr (assoc 10 (entget topline))))) "," (rtos (car (cdr (cdr (assoc 10 (entget topline))))))))
                (setq xy3 (strcat (rtos (car (cdr (assoc 10 (reverse (entget (entlast))))))) "," (rtos (car (cdr (cdr (assoc 10 (reverse (entget (entlast))))))))))
                (setq xy4 (strcat (rtos (car (cdr (assoc 10 (reverse (entget topline)))))) "," (rtos (car (cdr (cdr (assoc 10 (reverse (entget topline)))))))))
                (command "_PLINE" xy1 xy2 "")
                (command "_PLINE" xy3 xy4 "")
                (setvar "peditaccept" 0)
        )
        (t
                (princ "*Cancel*")
        )
)
(command "UNDO" "END")
(setvar "cmdecho" 1)
(princ)
)

try math [color="blue"]cos[/color] or [color="blue"]sin [/color] &[color="blue"] abs[/color]
(defun foo (x a)(/ x ([color="blue"]cos [/color]a ) ))
;(foo 1. (/ pi 4.))
(foo 1. (angle '(0 0)'(1 1)))
(foo 1. (angle '(1 1)'(2 0))) 
[color="green"];1.41421 to be extended?[/color]