多段线点集最小包围盒

/db_自贡黄明儒_ · 发表于 2017-12-10 14:26:58

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;;[功能] 点集包围盒--短边最短
;;(_EntmakeLWPOLYLINE (_BoxminB (_HH:GetLwPts (car (entsel)))))
(defun _BoxminB (P / A ANG B C L P1 P2 S X)
(setq p1 p)
(setq p2 (cons (last p) p))
(while (setq a (car p1))
(setq p1 (cdr p1))
(setq b (car p2))
(setq p2 (cdr p2))
(setq ang (- (angle a b)))
(setq c (mapcar '(lambda (x) (rotate_pnt x a ang)) p))
(setq c (list
(apply 'mapcar (cons 'min c))
(apply 'mapcar (cons 'max c))
)
)
(setq c (_pnts:box c))
;;最小面积
(setq s (min (distance (car c) (cadr c))
(distance (cadr c) (caddr c))
)
)
(setq c (mapcar '(lambda (x) (rotate_pnt x a (- ang))) c))
(setq L (cons (list s c) L))
)
(cadar (vl-sort L '(lambda(x y) (< (car x)(car y)))))
)
;;[功能] 点集包围盒--最小面积
;;(_EntmakeLWPOLYLINE (_BoxminA (_HH:GetLwPts (car (entsel)))))
(defun _BoxMinA (P / A ANG B C L P1 P2 S X)
(setq p1 p)
(setq p2 (cons (last p) p))
(while (setq a (car p1))
(setq p1 (cdr p1))
(setq b (car p2))
(setq p2 (cdr p2))
(setq ang (- (angle a b)))
(setq c (mapcar '(lambda (x) (rotate_pnt x a ang)) p))
(setq c (list
(apply 'mapcar (cons 'min c))
(apply 'mapcar (cons 'max c))
)
)
(setq c (_pnts:box c))
;;最小面积
(setq s (* (distance (car c) (cadr c))
(distance (cadr c) (caddr c))
)
)
(setq c (mapcar '(lambda (x) (rotate_pnt x a (- ang))) c))
(setq L (cons (list s c) L))
)
(cadar (vl-sort L '(lambda (x y) (< (car x) (car y)))))
)
;;[功能] 点集包围盒--最小周长
;;(_EntmakeLWPOLYLINE (_BoxminL (_HH:GetLwPts (car (entsel)))))
(defun _BoxMinL (P / A ANG B C L P1 P2 S X)
(setq p1 p)
(setq p2 (cons (last p) p))
(while (setq a (car p1))
(setq p1 (cdr p1))
(setq b (car p2))
(setq p2 (cdr p2))
(setq ang (- (angle a b)))
(setq c (mapcar '(lambda (x) (rotate_pnt x a ang)) p))
(setq c (list
(apply 'mapcar (cons 'min c))
(apply 'mapcar (cons 'max c))
)
)
(setq c (_pnts:box c))
;;最小面积
(setq s (+ (distance (car c) (cadr c))
(distance (cadr c) (caddr c))
)
)
(setq c (mapcar '(lambda (x) (rotate_pnt x a (- ang))) c))
(setq L (cons (list s c) L))
)
(cadar (vl-sort L '(lambda(x y) (< (car x)(car y)))))
)

;;[功能] 点集包围盒--短边最短 
;;(_EntmakeLWPOLYLINE (_BoxminB (_HH:GetLwPts (car (entsel))))) 
(defun _BoxminB (P / A ANG B C L P1 P2 S X) 
  (setq p1 p) 
  (setq p2 (cons (last p) p)) 
  (while (setq a (car p1)) 
    (setq p1 (cdr p1)) 
    (setq b (car p2)) 
    (setq p2 (cdr p2)) 
    (setq ang (- (angle a b))) 
    (setq c (mapcar '(lambda (x) (rotate_pnt x a ang)) p)) 
    (setq c (list 
               (apply 'mapcar (cons 'min c)) 
               (apply 'mapcar (cons 'max c)) 
             ) 
    ) 
    (setq c (_pnts:box c)) 
    ;;最小面积 
    (setq s (min (distance (car c) (cadr c)) 
               (distance (cadr c) (caddr c)) 
            ) 
    ) 
    (setq c (mapcar '(lambda (x) (rotate_pnt x a (- ang))) c)) 
    (setq L (cons (list s c) L)) 
  ) 
  (cadar (vl-sort L '(lambda(x y) (< (car x)(car y))))) 
) 
 
;;[功能] 点集包围盒--最小面积 
;;(_EntmakeLWPOLYLINE (_BoxminA (_HH:GetLwPts (car (entsel))))) 
(defun _BoxMinA (P / A ANG B C L P1 P2 S X) 
  (setq p1 p) 
  (setq p2 (cons (last p) p)) 
  (while (setq a (car p1)) 
    (setq p1 (cdr p1)) 
    (setq b (car p2)) 
    (setq p2 (cdr p2)) 
    (setq ang (- (angle a b))) 
    (setq c (mapcar '(lambda (x) (rotate_pnt x a ang)) p)) 
    (setq c (list 
              (apply 'mapcar (cons 'min c)) 
              (apply 'mapcar (cons 'max c)) 
            ) 
    ) 
    (setq c (_pnts:box c)) 
    ;;最小面积 
    (setq s (* (distance (car c) (cadr c)) 
               (distance (cadr c) (caddr c)) 
            ) 
    ) 
    (setq c (mapcar '(lambda (x) (rotate_pnt x a (- ang))) c)) 
    (setq L (cons (list s c) L)) 
  ) 
  (cadar (vl-sort L '(lambda (x y) (< (car x) (car y))))) 
) 
 
;;[功能] 点集包围盒--最小周长 
;;(_EntmakeLWPOLYLINE (_BoxminL (_HH:GetLwPts (car (entsel))))) 
(defun _BoxMinL (P / A ANG B C L P1 P2 S X) 
  (setq p1 p) 
  (setq p2 (cons (last p) p)) 
  (while (setq a (car p1)) 
    (setq p1 (cdr p1)) 
    (setq b (car p2)) 
    (setq p2 (cdr p2)) 
    (setq ang (- (angle a b))) 
    (setq c (mapcar '(lambda (x) (rotate_pnt x a ang)) p)) 
    (setq c (list 
              (apply 'mapcar (cons 'min c)) 
              (apply 'mapcar (cons 'max c)) 
            ) 
    ) 
    (setq c (_pnts:box c)) 
    ;;最小面积 
    (setq s (+ (distance (car c) (cadr c)) 
               (distance (cadr c) (caddr c)) 
            ) 
    ) 
    (setq c (mapcar '(lambda (x) (rotate_pnt x a (- ang))) c)) 
    (setq L (cons (list s c) L)) 
  ) 
  (cadar (vl-sort L '(lambda(x y) (< (car x)(car y))))) 
)

marting · 发表于 2017-12-10 14:29:29

看看黄总的代码。

marting · 发表于 2017-12-10 14:46:44

是不是做个通用的点集的最小包围盒更好呢？如果是多段线的话，求出顶点表，然后调用这个函数。

liunian0524 · 发表于 2017-12-10 16:55:36

感谢黄大侠的分享

/db_自贡黄明儒_ · 发表于 2017-12-10 18:20:48

本帖最后由 /db_自贡黄明儒_ 于 2017-12-10 19:29 编辑

marting 发表于 2017-12-10 14:46

后来我想了一下，以上方法并不严谨，还是要先凸包扫描。highflybird大师发的那个MinAreaRectangle确实难理解，我这个通俗些。

aeo · 发表于 2017-12-10 22:28:46

aeo，如果您要查看本帖隐藏内容请回复

aeo · 发表于 2017-12-10 23:00:34

c++代码在这里，需要转换成 arx
http://blog.csdn.net/mypsq/article/details/40076075

描述过程在这里，反正光看描述，是没法理解的
http://bbs.xdcad.net/thread-706965-1-1.html

newer · 发表于 2017-12-10 23:28:50

/db_自贡黄明儒_ 发表于 2017-12-10 18:20

用凸包，那不就是旋转卡壳法了嘛。

sicky111 · 发表于 2017-12-11 00:01:58

回复看看。

HLCAD · 发表于 2017-12-11 08:41:34

感谢黄大侠的分享程序

yjch · 发表于 2017-12-11 08:54:03

谢谢，思路打开，好好学习天天向上

819534890 · 发表于 2017-12-11 11:00:03

回复学习，学习分享

yoyoho · 发表于 2017-12-11 11:19:39

感谢分享学习！！！

q3_2006 · 发表于 2017-12-11 12:02:20

(list (apply 'mapcar (cons 'min pts)) (apply 'mapcar (cons 'max pts)))
跟这个有什么不同??

marting · 发表于 2017-12-11 12:11:47

q3_2006 发表于 2017-12-11 12:02

点集最小包围盒，不一定是正交方向的矩形框

搜狗截图20171211121142.png

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[原创] 多段线点集最小包围盒

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