Verify Image exists. Crashes if no image exists.

[jlogan02]

Currently this works if there is an image in the drawing.

(setq Img1 (ssget "x" '((0 . "image"))))
  (if (Tblsearch "Layer" "Image")
    (command "_Layer" "m" "Image" "")
    (command "_chprop" Img1 "" "LA" "Image" "" ""))
    (command "_layer" "S" "Line1" "Freeze" "Image" "")

It doesn't work if there isn't an image in the drawing.
I'm missing something simple, I'm sure.

J. Logan

[BlackBox]

Give this a try:

(vl-load-com)

(defun c:FOO (/ *error* acDoc layerName oLayer ss)

  (defun *error* (msg)
    (if ss
      (vla-delete ss)
    )
    (if acDoc
      (progn
        (vla-endundomark acDoc)
        (vla-regen acDoc acallviewports)
      )
    )
    (cond ((not msg))                                                   ; Normal exit
          ((member msg '("Function cancelled" "quit / exit abort")))    ; <esc> or (quit)
          ((princ (strcat "\n** Error: " msg " ** ")))                  ; Fatal error, display it
    )
    (princ)
  )

  (if (ssget "_:L" '((0 . "IMAGE") (8 . "~Image")))
    (progn
      (vla-startundomark
        (setq acDoc (vla-get-activedocument (vlax-get-acad-object)))
      )

      ;; get or create layer
      (setq oLayer
             (vla-add (vla-get-layers acDoc) (setq layerName "Image"))
      )

      ;; set image layer
      (vlax-for x (setq ss (vla-get-activeselectionset acDoc))
        (vla-put-layer x layerName)
      )

      ;; freeze image layer, set clayer
      (vla-put-freeze oLayer :vlax-true)
      (setvar 'clayer "Line1")
    )
  )

  (*error* nil)
)

Cheers

[jlogan02]

Give this a try:

(vl-load-com)

(defun c:FOO (/ *error* acDoc layerName oLayer ss)

  (defun *error* (msg)
    (if ss
      (vla-delete ss)
    )
    (if acDoc
      (progn
        (vla-endundomark acDoc)
        (vla-regen acDoc acallviewports)
      )
    )
    (cond ((not msg))                                                   ; Normal exit
          ((member msg '("Function cancelled" "quit / exit abort")))    ; <esc> or (quit)
          ((princ (strcat "\n** Error: " msg " ** ")))                  ; Fatal error, display it
    )
    (princ)
  )

  (if (ssget "_:L" '((0 . "IMAGE") (8 . "~Image")))
    (progn
      (vla-startundomark
        (setq acDoc (vla-get-activedocument (vlax-get-acad-object)))
      )

      ;; get or create layer
      (setq oLayer
             (vla-add (vla-get-layers acDoc) (setq layerName "Image"))
      )

      ;; set image layer
      (vlax-for x (setq ss (vla-get-activeselectionset acDoc))
        (vla-put-layer x layerName)
      )

      ;; freeze image layer, set clayer
      (vla-put-freeze oLayer :vlax-true)
      (setvar 'clayer "Line1")
    )
  )

  (*error* nil)
)

Cheers

That works nicely thanks.

I'm getting a select objects prompt to put the .CAL file on the "Image" layer at the end when I run it.

;; freeze image layer, set clayer
      (vla-put-freeze oLayer :vlax-true)
      (setvar 'clayer "Line1")
    )
  )

I'm not terribly fluent here, is this freezing the Image layer once the .CAL file is on the image layer. Or is it supposed to be?

[BlackBox]

Yeah, I was confused by that as well - the last line of your original LISP above, sets "Line1" layer current, then freezes "Image" layer - so I included in my quick adaptation.

If those steps aren't needed (as shown in OP code), just comment them out, or remove them altogether.


Cheers

[jlogan02]

I suppose I should have told the whole story.

I'm going through the process of replacing our old title blocks with an attributed title block. Seems easy enough but someone updated the Title block template so I have to replace the outdated Border and Title block in existing drawings at the same time. Some drawings have .CAL files in them while some don't. I need to protect against erasing the .CAL file when erasing the old Border and Title block via lisp.

Happily the powers that be don't believe in using blocks or object based layer names. So I'm relegated to hunting down each specific entity that is the border and Title block while also preserving the original content within both. the guts if you will. A lot of freezing and thawing going on.

My first move is to see if an image (.CAL file) exists. If so make sure the .CAL image is on the correct layer and freeze the layer to avoid being erased or manipulated during the greater lisp operation and then thawed once the operation is complete. If the .CAL doesn't exist, do nothing and move on. That was what the OP was about. Making sure the .CAL file is preserved during the run of the lisp routine if indeed the .CAL file exists.

Upon further inspection, your addition to my routine is asking for a selection of the .CAL file in a drawing where one doesn't exist. I was trying to make it so the user doesn't have to do anything.

[BlackBox]

No worries, thanks for clarifying.

Up to you on how to proceed - anything I post, you can take and modify how you see fit, no attribution needed.

Now, the code above doesn't test for .CAL file extension, it just handles all images, but it can if you need it to?

Also be mindful, that freezing doesn't prevent deletion, only graphical selection; to prevent deletion, simply lock the layer instead.


If you've got more information that you can post, I can better streamline what I've already posted; just be sure to identify any prudent conditions, or if-then situations, and I'll help where I can.

Cheers