Setting an Emacs background image

Question

Emacs 23 just added the functionality to change the alpha value of the current frame to make it transparent. I just type the following command in .emacs:

(set-frame-parameter (selected-frame) 'alpha '(85 50))

It actually shows what's on the windows behind Emacs. However, I would be interested in making an Emacs background image instead. Maybe of some stellar landscape or something. Does anyone have ideas on how to change the background image behind the frame?

Answer 1

This doesn't appear possible at a glance. Below are the frame parameters that can be set:

• auto-raise
• auto-lower
• background-color
• border-color
• border-width
• cursor-color
• cursor-type
• font
• foreground-color
• icon-name
• icon-type
• internal-border-width
• menu-bar-lines
• mouse-color
• name
• scroll-bar-width
• title
• unsplittable
• vertical-scroll-bars
• visibility
• tool-bar-lines
• scroll-bar-foreground
• scroll-bar-background
• screen-gamma
• line-spacing
• left-fringe
• right-fringe
• wait-for-wm
• fullscreen
• font-backend
• alpha
• sticky

Answer 2

I used to build from source just so I could use the patch at http://umiushi.com/~wac/bgex/, but that doesn't work on Mac (and probably not Windows). It allows you to put a different background on different buffers based on filename or major-mode. I liked it a lot.

One thing that almost works is to set the stipple for the default face M-x customize-face RET default RET to a file. For me this ends up being worse than nothing though since it only adds a background image to the portion of the buffer with text in it (at least on OS X). I learned about this by asking on emacs-devel http://lists.gnu.org/archive/html/emacs-devel/2009-06/msg00477.html.

You may also find http://www.emacswiki.org/emacs/TransparentEmacs useful.