Topic: How do you simplify a LWPolyline vertex?

[wizman]

i agree kerry, i can say that CAB is not selfish with his codes thank you for that.

[CAB]

Well thanks for the complement Kerry and you too Wizman.

[Joe Burke]

Alan,

Using 2008, version 1.5 works with the closed (upper) pline but not with the open (lower) one in my example file.

Are you getting the same result?

[Joe Burke]

Alan,

Something I tried while playing with my version. Pre-process the pline to remove duplicate adjacent points. Such a sub-function may not be as easy as it seems at first glance. But it may simplify the primary function significantly.

Just a thought...

[CAB]

Alan,

Using 2008, version 1.5 works with the closed (upper) pline but not with the open (lower) one in my example file.

Are you getting the same result?

Yes, same result & that is intentional.
In my way of thinking it would need to be a closed pline before meeting the criterion to simplify.
I suppose I may have missed that aspect in this discussion. If the pline is open as in the lower example would the desired result
be a closed pline or and open pline with the start/end vertexes at a corner?

[Joe Burke]

Yes, same result & that is intentional.
In my way of thinking it would need to be a closed pline before meeting the criterion to simplify.
I suppose I may have missed that aspect in this discussion. If the pline is open as in the lower example would the desired result
be a closed pline or and open pline with the start/end vertexes at a corner?

Alan,

I think the primary criterion to simplify is any collinear vertex should be removed. So the result with the plines in my example file should be the same in the sense there should be a selection grip at each corner and nowhere else.

Whether the closed pline ends up closed and the open pline ends up open doesn't really matter in the sense an attempt to edit/stretch any grip will behave the same... I think.

IOW, I don't think an open pline must remain open after simplify in this case.

[CAB]

Here is what I came up with. It closes the pline when the start & end points are the same.
Had to deal with a case where the start & end segment are arcs on open plines.
This case has an ending vertex that has to be removed to get the two arcs to join.

Code: [Select]

;;;=======================[ PSimple.lsp ]=======================
;;; Author: Charles Alan Butler
;;; Version:  1.6 Nov. 21, 2007
;;; Purpose: To remove unnecessary vertex from a pline
;;; Supports arcs and varying widths
;;;=============================================================
;; This version will remove the first vertex if it is colinear
;; and first & last arcs that have the same center
(defun c:PSimple (/      aa     cpt    dir    doc    elst   ent    hlst
                  idx    keep   len    newb   result vlst   x      closed
                  d10    d40    d41    d42    hlst   p1     p2     p3
                  plast remove  BulgeCenter   RemoveNlst   
                  )
  (vl-load-com)

  (defun tan (a) (/ (sin a) (cos a)))

  (defun replace (lst i itm)
    (setq i (1+ i))
    (mapcar '(lambda (x) (if (zerop (setq i (1- i))) itm x)) lst)
  )

 
  ;;  CAB 11.16.07
  ;;  Remove based on pointer list
  (defun RemoveNlst (nlst lst)
    (setq i -1)
    (vl-remove-if  '(lambda (x) (not (null (vl-position (setq i (1+ i)) nlst)))) lst)
  )
 
  (defun BulgeCenter (bulge p1 p2 / delta chord radius center)
    (setq delta  (* (atan bulge) 4)
          chord  (distance p1 p2)
          radius (/ chord (sin (/ delta 2)) 2)
          center (polar p1 (+ (angle p1 p2) (/ (- pi delta) 2)) radius)
    )
  )


  ;;  ========  S T A R T   H E R E  ===========
  (setq doc (vla-get-activedocument (vlax-get-acad-object)))
  (vla-startundomark doc)
  (setq ent (car (entsel "\n Select polyline to remove extra vertex: ")))
  (if (and ent
           (setq elst (entget ent))
           (equal (assoc 0 elst) '(0 . "LWPOLYLINE"))
      )
    (progn
      ;;=====================================================
      (setq d10 (mapcar 'cdr (vl-remove-if-not '(lambda (x) (= (car x) 10)) elst)))
      (if (> (length d10) 2)
        (progn
          ;;  seperate vertex data
          (setq d40 (vl-remove-if-not '(lambda (x) (= (car x) 40)) elst))
          (setq d41 (vl-remove-if-not '(lambda (x) (= (car x) 41)) elst))
          (setq d42 (mapcar 'cdr (vl-remove-if-not '(lambda (x) (= (car x) 42)) elst)))
          ;;  remove extra vertex from point list
          (setq plast (1- (length d10)))
          (setq p1 0  p2 1  p3 2)
          (if (and (not (setq closed (vlax-curve-isclosed ent)))
                   (equal (car d10) (last d10) 1e-6))
            (progn
              (setq Closed t ; close the pline
                    elst (subst (cons 70 (1+(cdr(assoc 70 elst))))(assoc 70 elst) elst))
              (if (and (not(zerop (nth plast d42)))(not(zerop (nth 0 d42))))
                (setq d10 (reverse(cdr(reverse d10)))
                      d40 (reverse(cdr(reverse d40)))
                      d41 (reverse(cdr(reverse d41)))
                      d42 (reverse(cdr(reverse d42)))
                      plast (1- plast)
                )
              )
            )
          )
          (setq idx -1)
          (while (<= (setq idx (1+ idx)) (if closed (+ plast 2) (- plast 2)))
            (cond
              ((and (or (equal (angle (nth p1 d10) (nth p2 d10))
                               (angle (nth p2 d10) (nth p3 d10)) 1e-6)
                        (equal (nth p1 d10) (nth p2 d10) 1e-6)
                        (equal (nth p2 d10) (nth p3 d10) 1e-6))
                    (zerop (nth p2 d42))
                    (or (= p1 plast)
                        (zerop (nth p1 d42)))
               )
               (setq remove (cons p2 remove)) ; build a pointer list
               (setq p2 (if (= p2 plast) 0 (1+ p2))
                     p3 (if (= p3 plast) 0 (1+ p3))
               )
              )
              ((and (not (zerop (nth p2 d42)))
                    (or closed (/= p1 plast))
                    (not (zerop (nth p1 d42))) ; got two arcs
                    (equal
                      (setq cpt (BulgeCenter (nth p1 d42) (nth p1 d10) (nth p2 d10)))
                      (BulgeCenter (nth p2 d42) (nth p2 d10) (nth p3 d10))
                      1e-4)
               )
               ;;  combine the arcs
               (setq aa   (+ (* 4 (atan (abs (nth p1 d42))))(* 4 (atan (abs (nth p2 d42)))))
                     newb (tan (/ aa 4.0))
               )
               (if (minusp (nth p1 d42))
                 (setq newb (- (abs newb)))
                 (setq newb (abs newb))
               )
               (setq remove (cons p2 remove)) ; build a pointer list
               (setq d42 (replace d42 p1 newb))
               (setq p2 (if (= p2 plast) 0 (1+ p2))
                     p3 (if (= p3 plast) 0 (1+ p3))
               )
              )
              (t
               (setq p1 p2
                     p2 (if (= p2 plast) 0 (1+ p2))
                     p3 (if (= p3 plast) 0 (1+ p3))
               )
              )
            )
          )
          (if remove
            (progn
              ;; Rebuild the vertex data with pt, start & end width, bulge
              (setq d10 (RemoveNlst remove d10)
                    d40 (RemoveNlst remove d40)
                    d41 (RemoveNlst remove d41)
                    d42 (RemoveNlst remove d42)
              )
              (setq result (mapcar '(lambda(w x y z) (list(cons 10 w)
                                        x  y
                                        (cons 42 z))) d10 d40 d41 d42)
              )
              ;;  rebuild the entity data with new vertex data
              (setq hlst (vl-remove-if
                           '(lambda (x) (vl-position (car x) '(40 41 42 10))) elst)
              )
              (mapcar '(lambda (x) (setq hlst (append hlst x))) result)
              (setq hlst (subst (cons 90 (length result)) (assoc 90 hlst) hlst))
              (entmod hlst)
            )
            (prompt "\nNothing to remove.")
          )
        )
        (prompt "\nNothing to do - Only two vertex.")
      )
    )
    (prompt "\nError - Not a LWpolyline.")
  )
  (vla-endundomark doc)
  (princ)
)
(prompt "\nPline Simplify loaded, PSimple to run.")
(princ)

[LE]

...

PS: what you guys have done so far it is excellent - keep it that way!

[CAB]

Hello David.
Trying to run your routine ypu have missing subroutines.
dat_vtx
eqp1

[Joe Burke]

Alan,

Version 1.6 is perfect. Nice work and many thanks.

I hope you agree with the recent changes.

[CAB]

That was fine with me as I had no personal requirements.
I did revise the code above just now [ver 1.6], removing 3 lines of stray code from an earlier test version.
They did no harm but garbage none the less.

I suppose the only thing left to do is modify to except a selection set ILO single select.

Off to Ocala, see you Friday night.

[Joe Burke]

I suppose the only thing left to do is modify to except a selection set ILO single select.

Alan,

I would change it to require an ename or vla-object argument so other functions can call it as need be. I'm not sure what it would return. Maybe the number vertices removed. If zero, the pline was not modified.

[CAB]

Thanks David. I'll check it out.

[CAB]

Here is my first run at the modified user interface.

Code: [Select]

;;;=======================[ PSimple.lsp ]=======================
;;; Author: Charles Alan Butler
;;; Version:  1.7 Nov. 24, 2007
;;; Purpose: To remove unnecessary vertex from a pline
;;; Supports arcs and varying widths
;;;=============================================================
;; This version will remove the first vertex if it is colinear
;; and first & last arcs that have the same center

;;  command line entry, user selection set pick
(defun c:PSimple () (PSimpleUser nil)(princ))
(defun c:PSimpleV () ; Verbose version
  (mapcar '(lambda(x)(print (car x))(princ (cadr x))) (PSimpleUser nil))
  (princ)
)

;;  User interface Function
;;  flag = nil -> user selects a selection set
;;       = ENAME -> call the routine
;;       = OBJECT -> call the routine
;;       = True   -> User to select a single entity, repeats
(defun PSimpleUser (flag / ss ent)
  (cond
    ((null flag)    ; user selection set pick
     (prompt "\n Select polylines to remove extra vertex: ")
     (if (setq ss (ssget '((0 . "LWPOLYLINE"))))
       (PSimple ss)
     )
    )
    ;;  next two already have an object so pass to the main routine
    ((= (type flag) 'ENAME) (PSimple flag))
    ((= (type flag) 'VLA-object) (PSimple flag))
    (t  ; user single pick with repeat
       (while
         (setq ent (car (entsel "\n Select polyline to remove extra vertex: ")))
          (if (equal (assoc 0 (entget ent)) '(0 . "LWPOLYLINE"))
            (PSimple ent)
            (prompt "\nNot a LWPolyline, Try again.")
          )
       )
    )
  )
)





;;;=======================[ PSimple.lsp ]=======================
;;; Author: Charles Alan Butler
;;; Version:  1.7 Nov. 23, 2007
;;; Purpose: To remove unnecessary vertex from a pline
;;; Supports arcs and varying widths
;;;=============================================================
;; This version will remove the first vertex if it is colinear
;; and first & last arcs that have the same center
;; Open plines that have the same start & end point will be closed

;;  Argument: et
;;    may be an ename, Vla-Object, list of enames or
;;    a selection set
;;  Returns: a list, (ename message)
;;    Massage is number of vertex removed or error message string
;;    If a list or selection set a list of lists is returned
(defun PSimple (et / doc result Tan Replace BulgeCenter RemoveNlst ps1)
  (vl-load-com)

  (defun tan (a) (/ (sin a) (cos a)))

  (defun replace (lst i itm)
    (setq i (1+ i))
    (mapcar '(lambda (x) (if (zerop (setq i (1- i))) itm x)) lst)
  )

 
  ;;  CAB 11.16.07
  ;;  Remove based on pointer list
  (defun RemoveNlst (nlst lst)
    (setq i -1)
    (vl-remove-if  '(lambda (x) (not (null (vl-position (setq i (1+ i)) nlst)))) lst)
  )
 
  (defun BulgeCenter (bulge p1 p2 / delta chord radius center)
    (setq delta  (* (atan bulge) 4)
          chord  (distance p1 p2)
          radius (/ chord (sin (/ delta 2)) 2)
          center (polar p1 (+ (angle p1 p2) (/ (- pi delta) 2)) radius)
    )
  )

  ;;  Main function to remove vertex
  ;;  ent must be an ename of a LWPolyline
  (defun ps1 (ent /      aa     cpt    dir    doc    elst   hlst   Remove
                  idx    keep   len    newb   result vlst   x      closed
                  d10    d40    d41    d42    hlst   p1     p2     p3
                  plast  msg)
      ;;=====================================================
      (setq elst (entget ent)
            msg  "")
      (setq d10 (mapcar 'cdr (vl-remove-if-not '(lambda (x) (= (car x) 10)) elst)))
      (if (> (length d10) 2)
        (progn
          ;;  seperate vertex data
          (setq d40 (vl-remove-if-not '(lambda (x) (= (car x) 40)) elst))
          (setq d41 (vl-remove-if-not '(lambda (x) (= (car x) 41)) elst))
          (setq d42 (mapcar 'cdr (vl-remove-if-not '(lambda (x) (= (car x) 42)) elst)))
          ;;  remove extra vertex from point list
          (setq plast (1- (length d10)))
          (setq p1 0  p2 1  p3 2)
          (if (and (not (setq closed (vlax-curve-isclosed ent)))
                   (equal (car d10) (last d10) 1e-6))
            (progn
              (setq Closed t ; close the pline
                    elst (subst (cons 70 (1+(cdr(assoc 70 elst))))(assoc 70 elst) elst)
                    msg  " Closed and")
              (if (and (not(zerop (nth plast d42)))(not(zerop (nth 0 d42))))
                (setq d10 (reverse(cdr(reverse d10)))
                      d40 (reverse(cdr(reverse d40)))
                      d41 (reverse(cdr(reverse d41)))
                      d42 (reverse(cdr(reverse d42)))
                      plast (1- plast)
                )
              )
            )
          )
          (setq idx -1)
          (while (<= (setq idx (1+ idx)) (if closed (+ plast 2) (- plast 2)))
            (cond
              ((and (or (equal (angle (nth p1 d10) (nth p2 d10))
                               (angle (nth p2 d10) (nth p3 d10)) 1e-6)
                        (equal (nth p1 d10) (nth p2 d10) 1e-6)
                        (equal (nth p2 d10) (nth p3 d10) 1e-6))
                    (zerop (nth p2 d42))
                    (or (= p1 plast)
                        (zerop (nth p1 d42)))
               )
               (setq remove (cons p2 remove)) ; build a pointer list
               (setq p2 (if (= p2 plast) 0 (1+ p2))
                     p3 (if (= p3 plast) 0 (1+ p3))
               )
              )
              ((and (not (zerop (nth p2 d42)))
                    (or closed (/= p1 plast))
                    (not (zerop (nth p1 d42))) ; got two arcs
                    (equal
                      (setq cpt (BulgeCenter (nth p1 d42) (nth p1 d10) (nth p2 d10)))
                      (BulgeCenter (nth p2 d42) (nth p2 d10) (nth p3 d10))
                      1e-4)
               )
               ;;  combine the arcs
               (setq aa   (+ (* 4 (atan (abs (nth p1 d42))))(* 4 (atan (abs (nth p2 d42)))))
                     newb (tan (/ aa 4.0))
               )
               (if (minusp (nth p1 d42))
                 (setq newb (- (abs newb)))
                 (setq newb (abs newb))
               )
               (setq remove (cons p2 remove)) ; build a pointer list
               (setq d42 (replace d42 p1 newb))
               (setq p2 (if (= p2 plast) 0 (1+ p2))
                     p3 (if (= p3 plast) 0 (1+ p3))
               )
              )
              (t
               (setq p1 p2
                     p2 (if (= p2 plast) 0 (1+ p2))
                     p3 (if (= p3 plast) 0 (1+ p3))
               )
              )
            )
          )
          (if remove
            (progn
              (setq count (length d10))
              ;; Rebuild the vertex data with pt, start & end width, bulge
              (setq d10 (RemoveNlst remove d10)
                    d40 (RemoveNlst remove d40)
                    d41 (RemoveNlst remove d41)
                    d42 (RemoveNlst remove d42)
              )
              (setq result (mapcar '(lambda(w x y z) (list(cons 10 w)
                                        x  y
                                        (cons 42 z))) d10 d40 d41 d42)
              )
              ;;  rebuild the entity data with new vertex data
              (setq hlst (vl-remove-if
                           '(lambda (x) (vl-position (car x) '(40 41 42 10))) elst)
              )
              (mapcar '(lambda (x) (setq hlst (append hlst x))) result)
              (setq hlst (subst (cons 90 (length result)) (assoc 90 hlst) hlst))
              (if (entmod hlst); return ename and number of vertex removed
                (list ent (strcat msg " Vertex removed " (itoa(- count (length d10)))))
                (list ent " Error, may be on locked layer.")
              )
            )
            (list ent "Nothing to remove - no colenier vertex.")
          )
        )
        (list ent "Nothing to do - Only two vertex.")
      )
    )
 

  ;;  ========  S T A R T   H E R E  ===========
  (setq doc (vla-get-activedocument (vlax-get-acad-object)))
  (cond
    ((or (=(type et) 'ENAME)
         (and (=(type et) 'VLA-object)
              (setq et (vlax-vla-object->ename et))))
      (vla-startundomark doc)
      (setq result (ps1 et))
      (vla-endundomark doc)
     )
    ((= (type et) 'PICKSET)
      (vla-startundomark doc)
      (setq result (mapcar '(lambda(x) (ps1 x))
              (vl-remove-if 'listp (mapcar 'cadr (ssnamex ss)))))
      (vla-endundomark doc)
    )
    ((listp et)
      (vla-startundomark doc)
      (setq result (mapcar '(lambda(x) (ps1 x)) et))
      (vla-endundomark doc)
    )
    ((setq result "PSimple Error - Wrong Data Type."))
  )
  result
)
(prompt "\nPline Simplify loaded, PSimple to run.")
(princ)

[LE]

Alan,

Your routine, does a great job.... I am removing the one I posted, it is super mickey mouse, compared with this one.