;Tip1556:  TR.LSP    Text Rotate    (C)1999, William E. Barlow
;Published in Cadalyst Magazine September 1999 issue in the Hot Tip Harry Section
:http://cadtips.cadalyst.com/node/tiplisting?keywords=Tip1556

; This LISP routine allows the user to select a line (Not a pline)
; and then select text (Not MText) and the text rotates to the
; angle of the line


(defun C:TR  ()
  (setvar "CMDECHO" 0)
  (prompt "\nSelect Line: ") 		; select object line
  (setq LINE (ssget))			; get selection set of line
  (setq INDEX 0)			; establish an index
  (setq ENAME (ssname LINE INDEX))	; give a name to the line
  (setq ELIST (entget ENAME))		; create a list
  (setq PT1 (cdr (assoc 10 ELIST)))	; get end pt1 x,y,z values from set
  (setq VALUE11 (car PT1))		; get x coordinate pt1
  (setq VALUE12 (cadr PT1))		; get y coordinate pt1
  (setq VALUE13 (caddr PT1))		; get z coordinate pt1
  (setq PT2 (cdr (assoc 11 ELIST)))	; get end pt2 x,y,z values
  (setq VALUE21 (car PT2))		; get x coordinate pt2
  (setq VALUE22 (cadr PT2))		; get y coordinate pt2
  (setq VALUE23 (caddr PT2))		; get z coordinate pt2
  (setq LANGLE (angle PT1 PT2))		; get angle of selected lline
  (setq P12 (/ pi 2.0))			; do calcs
  (setq P32 (* pi 1.5))
  (setq P2 (* pi 2.))
  (if (and (>= LANGLE 0.0) (<= LANGLE P12))
    (setq NARCTAN LANGLE))
  (if (and (>= LANGLE P32) (<= LANGLE P2))
    (setq NARCTAN LANGLE))
  (if (and (>= LANGLE P12) (<= LANGLE pi))
    (setq NARCTAN (+ LANGLE pi)))
  (if (and (>= LANGLE pi) (<= LANGLE P32))
    (setq NARCTAN (- LANGLE pi)))
  (prompt "\nSelect Text: ")		; select object text 
  (setq TEXTL (entget (car (entsel))))	; get selection set of text
  (setq OTEXT (assoc 50 TEXTL))		; get value from set
  (setq NTEXT (cons 50 NARCTAN))	; concatentate
  (setq TEXTL (subst NTEXT OTEXT TEXTL))
  (entmod TEXTL))			; Modify the definition data of an object (entity)