Elisp and overlay, how to show an image

["Sébastien Gendre" <seb@k-7.ch>]

Hello,

I am trying to show an image on the top of a buffer, before the first
line of text, and put a small margin at the bottom of the image.


I have read the Overlay manual [1] and the source code of the function
`org-display-inline-images`, but I have difficulties to understand how
to use overlay beginning and end parameters.


Here is the source code my first try:


    ;; Create an overlay at the first char of the buffer
    (setq ov1 (make-overlay 1 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)


When I evaluate this code, for example on the *scratch* buffer, I got a
new line before the first buffer char, but the image do not display.

Should I need to create, on the overlay, an empty space big enough to
put the image in it ? Or did I miss something on the manual ?



Best regards.


[1] https://www.gnu.org/software/emacs/manual/html_node/elisp/Overlays.html