Note: the feature described below is now available in the cutebar branch of my Emacs fork on GitHub.
A huge peeve of mine on OS X is the mixture of the (application) menu bar, starting on the left, and the status bar, starting on the right: when you have a lot of status indicators like me, even a reasonably sized application menu bar will irreparably hide a lot of status, which is really annoying.
One day, I had this idea that application menu bar (wide) titles could be replaced with (narrow) icons, hence leaving more space to the status bar. Of course, it shouldn't be up to the menu, or even to the application itself to choose which icon to use. It should be up to the user. A user will want a single icon set to work with all applications (e.g. you choose a nice File icon, and you want all applications to use it instead of the word "File").
So one day, I implemented a SIMBL plugin and preference pane for doing exactly that. Don't look for it, it's never been released. It lets the user create associations between menu titles and icons and hijacks OS X applications to modify the appearance of their menu bar. Alas, it doesn't work very well. Native Cocoa applications not doing anything fancy with their menus are ok, but most other applications are not.
Today, let me introduce some support for this feature in Emacs. Attached to this article is a patch against the current trunk plus a small image file. For this to work, you will need to put the image file (barsplit.png) in the etc/images/ directory of Emacs'source tree, apply the patch and recompile (--with-ns of course). Then, find yourself a nice set of icons and go customize the options menu-bar-use-icons, menu-bar-icons-directory and menu-bar-icons in the "menu" custom group. The docstrings should be self-explanatory. As you can see on the screenshot, what you get is a much narrower, visual menu bar. The first menu (the so-called "application menu") always uses the official application's icon. The other ones are your choice. Finally, the menu bar ends with a visual separator allowing to better distinguish its end from the start of the status bar.
The current implementation is very naive (sorry, I meant highly dynamic): titles / icons associations are recomputed every time the menu bar is redrawn. But this has in fact some advantages:
- the code is quite simple,
- customizations made by the user are visible immediately, without the need for a complex event listener / notification / whatever machinery (this machinery may already exist in the Emacs codebase though).
In fact, I've been using this patch for quite a while now and I didn't notice any performance impact on my 3 years-old Mac Book Pro. One last thing you need to know: the behavior of this feature may be unreliable (even if implemented correctly, which I think I did) because messing with the menu bar like this is uncharted territory, totally unsupported by Apple. Enjoy anyway :-)
Now, if somebody comes up with a nice and comprehensive set of menu bar icons for Emacs (and other OS X apps), I'd be delighted...
