Re: Elisp and overlay, how to show an image

[Stefan Monnier via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>]

> Here is the source code my first try:
>
>     ;; Create an overlay at the first char of the buffer
>     (setq ov1 (make-overlay 1 1))

Please use (point-min) rather than 1.

>     ;; Create the image from a file
>     (setq my_image (create-image "~/Path/to/my/image.jpg"))
>     
>     ;; Put a new line, to avoid aving the image replacing the first char
>     (overlay-put ov1 'before-string "\n")
>     
>     ;; Put the image on the overlay
>     (overlay-put ov1 'display my_image)

As Tomas points out, the `display` property is obeyed only if it covers
characters.  The usual way to "insert" an image without disrupting the
content of the buffer (e.g. in `put-image`) is to put the image (with
`display` property) on a *string* and then put that string in the
`before-string` (or `after-string`) property of an overlay.

    (let ((ol (put-image (create-image "~/Path/to/my/image.jpg")
                         (point-min))))
      (overlay-put ol 'after-string "\n"))


- Stefan