Test if viewport overlaps any text or linework

[GreyHippo]

Is there a way to test if a viewport overlaps any text or linework? Sometimes when a detail is revised, part of the detail is extended out past the viewport and therefore can't see it. I would like to have the program run each time the drawing is plotted.

[irneb]

Do you have all linework / text in Model Space always visible through a viewport? I.e. no temporary stuff around? Then it's possible to "extend" the viewport using some maths and properties like the viewport's Height, Width, Target & CustomScale. Then "summing" each MS entity's BoundingBox and seeing if any fall outside the viewport. Then it's probably possible to modify the viewport's Target, Width & Height to suit.

If you have some entities outside the viewport's view (and you want to leave them there) it may be a bit difficult. I'd suggest having a border in MS which can be "linked" to some XData of the viewport, so that the VP gets adjusted to suit the border. You could always place the border on a non-plot layer.

As for having it run each time you plot, it could be possible to "override" the plot command to do this first and then run the default plot. Otherwise (if you're using the border idea as above) an object reactor could be used which would adjust the viewport each time the border is modified.

[GreyHippo]

Usually there are other items outside the viewport that do not get shown in paperspace

[irneb]

In that case I'd advise going the Model Space border route. I can't see an easy way of doing it otherwise.

In which case you're going to see a lot about working with viewport scales (converting from MS 1=1 to PS scale and back). As well as using reactors & storing xdata links between entities. But if you get this right, it means you've got an adjustable border in MS which "duplicates" itself in PS as a viewport.

BTW, do you clip and/or rotate viewports? If so it's going to get really hairy .

I'd like to help, but unfortunately I've not got much time . You could search this forum for several examples to show how to use reactors, how to set & get xdata and how to convert points to-and-from PS & MS.

[GreyHippo]

I sometimes clip and rotate viewports. It sounds like this might be very difficult. I will experiment with a few things and post if I come up with anything.

[GreyHippo]

Irneb,

I am trying something that will work for viewports that are not rotated or clipped but I can' t figure out how to translate paperspace coordinates to modelspace coordinates.

How do you use the TRANS function to translate points PS to MS?

(defun rtd (a) (* (/ a pi) 180.0))

(defun dtr (a) (* (/ a 180.0) pi))

(defun c:vp_overlap (/ vp)
      (initerr)
      (setq vp (entget (car (entsel "\nSelect Viewport: "))))
      (setq vp_cp (cdr (assoc 10 vp)))
      (setq vp_w (cdr (assoc 40 vp)))
      (setq vp_h (cdr (assoc 41 vp)))

      (setq pt1 (polar (polar vp_cp (dtr 90) (/ vp_h 2)) (dtr 180) (/ vp_w 2)))
      (setq pt2 (polar (polar vp_cp (dtr 90) (/ vp_h 2)) (dtr 0) (/ vp_w 2)))
      (setq pt3 (polar (polar vp_cp (dtr 270) (/ vp_h 2)) (dtr 0) (/ vp_w 2)))
      (setq pt4 (polar (polar vp_cp (dtr 270) (/ vp_h 2)) (dtr 180) (/ vp_w 2)))

     (setq pt1 (trans pt1 2 0))
      (setq pt2 (trans pt2 2 0))
      (setq pt3 (trans pt3 3 2))
      (setq pt4 (trans pt4 3 2))

      (reset)
      (princ)
      )
(princ)

[alanjt]

This should help:
http://www.jtbworld.com/lisp/vp-outline.htm

and this:

(vlax-invoke Object1 'IntersectWith Object2 acExtendNoNe)