Displaying images in popup menus in Emacs

Question

I'm working on an Emacs mode for people learning Japanese. The point is to help them learn the stroke orders of various Japanese characters (especially kanji) by running a set of functions which extract the character at point and if it is a Japanese character, displaying an image with the stroke order. I have worked out almost all the details, but I have a question about displaying images. I'd like to be able to display the image object (obtained by create-image) in a popup menu anchored at point. Any hints on doing that? Alternatively I'd like to create a new temporary buffer displaying the image. I've tried using insert-image with the image object, but all I see in the resulting buffer is an empty rectangle where the image should be. How can I make a buffer with a visible image? Any help greatly appreciated.

Answer 1

Putting an image in a tooltip might help, as a start.

I do that in Dired+ -- see the code for diredp-mouseover-help and diredp-image-dired-create-thumb. This is the core of it:

• Unless image-dired-thumb-name says there is already a thumbnail for the image file, use image-dired-create-thumb to create one. This is the main part of diredp-image-dired-create-thumb.

• Display either the full image or a thumbnail in a tooltip on mouseover:

    (let ((img-file  (if (eq 'full diredp-image-preview-in-tooltip)
                         file
                       (diredp-image-dired-create-thumb file))))
      (propertize " " 'display (create-image img-file)))

A next step could be to put a keymap or local-map property on the image, with, say, a mouse-1 binding that acts as the choice action for that image choice. Just a thought - haven't tried it.

You would presumably want to put multiple images in the same tooltip, each with a different action function. Haven't tried that, but you might experiment.

HTH.