Stephan Sokolow's Blog

A couple of days ago, it finally occurred to me to look for a way to turn off the sluggish (on Linux, at least) drag-and-drop previews in Firefox. So, while I’m at it, I thought I’d list a few of the more interesting about:config keys which aren’t exposed by the Firefox 7 GUI.

Performance Tweaks

UI Customizations

“It’s My Computer”

Let me know if there’s anything I’ve missed.

Note: While this post focuses on zsh, everything I do should be possible to implement in bash too.

When I look at people’s shell prompts, the first thing I always seem to notice is that they’re bulky and eye-grabbing. Seeing a textual version of GNOME Panel get duplicated into my terminal after every command isn’t something that appeals to me, so I thought I’d come up with something just as useful, but a little more compact.

What follows is a step-by-step story, with pseudo-screenshots, of how I went from a bog-standard zsh prompt to a fairly advanced prompt that only looks different when it has something to say, ending in a link to the .zshrc source I use to actually implement it. Feel free to skip ahead.

Because I like the color scheme and because I already have it, I’m starting with the default Gentoo prompt:

ssokolow@monolith ~ %

Obviously, this already has the usual Gentoo prompt’s “you are root” indicators (user ID turns red and % turns into #) and the ability to tell zsh and bash apart at a glance (For those who don’t know, zsh uses % while bash uses $) but I do a lot of programming and I use git for all my code, so the most useful thing I could possibly add is a way to never forget which branch I’m working on. Thankfully, that’s already been done for me:

ssokolow@monolith quicktile [master] %

I’d also wanted a way to see, at a glance, whether there were any jobs running in the background. The %(1j.%%.) ternary expression fixed that one right up:

ssokolow@monolith quicktile [master] % git gui &
ssokolow@monolith quicktile [master] %%

Finally, not all of my programs are clear about when they send a non-zero exit code, so it’d be nice to know that too. Another ternary expression, namely %(0?..%F{yellow}), takes care of that:

ssokolow@monolith quicktile [master] % false
ssokolow@monolith quicktile [master] %

I like how the prompt, by default, only displays the last component of $PWD so I left that unchanged. You’re free to add in other things but I tend to struggle with performance issues when both Firefox and GCC have to fight for “only” 4GiB of RAM so I decided not to hook in any more subprocess calls.

A pruned-down, streamlined version of the code for it is available on GitHub as zshrc.d/gentoo_prompt_setup but you’ll also need this line from my master .zshrc:

typeset -ga precmd_functions

By a lucky coincidence, I discovered that PySolFC comes with a Clearlooks pixmap theme nicer than the built-in one I was using. Unfortunately, there seemed to be no documentation on how to install your own Ttk themes beyond forum posts saying “run the build scripts”. Geeking time!

After a little puttering around and a bit of uncertain code-diving (I don’t code TCL.), I figured out that all you have to do is grab your theme’s top-level directory (the one with pkgIndex.tcl) and put it somewhere TCL’s library loader can find it.

Here’s what I used on Gentoo Linux: (Roughly. I actually use zsh.)

mkdir -p ~/.local/share/tkthemes
cp -r /usr/share/games/pysolfc/themes/clearlooks ~/.local/share/tkthemes/
echo "export TCLLIBPATH=~/.local/share/tkthemes" >> ~/.bashrc
vim ~/.Xdefaults

Keep in mind that if you don’t either use startx to launch your X sessions or launch your Tk applications from a terminal, you’ll need to set TCLLIBPATH somewhere like ~/.kde4/env/set_ttk_theme.sh or ~/.xsessionrc instead.

UPDATE: In some Tk applications, you can force the menu bar to match the color of the Clearlooks Ttk theme by setting *background: #efebe7 in your ~/.Xresources file.

After getting fed up with Yakuake‘s bloat, Yeahconsole‘s broken embedding, and Tilda‘s flickering, broken scrollbar, and broken URL handling, I decided to try URxvt, since it has a Perl extension that’ll turn it into a slide-down terminal without being embedded in Yeahconsole.

(And because stjerm, though well-recommended by some, is the name of two seemingly independent Google Code projects and somehow feels just a touch shady to me)

After a few days of intermittent fiddling, my reactions were mixed:

Nonetheless, it’s generally a decent terminal and I’ve switched to its kuake Perl extension. It has its warts but, so far, I get the impression that URxvt’s warts won’t bother me as much as XTerm’s warts do.

Still, I did almost gave up on it several times before I stumbled on the little fix I needed and, if I weren’t procrastinating something else right now, I probably would have given up. In case anyone wants it for reference purposes, my URxvt config is up on GitHub.

^1. Manpages seem to be the source format and, even with table-of-contents generation and hyperlinking for the manpage cross-references in HTML and texinfo converters, it still involves a lot of fumbling, fiddling, and Ctrl+F-ing within too-long pages where there are no links direct to the relevant sections and quite a few “See the …” references which aren’t hyperlinked and don’t give any clue where to look for the materials suggested.

While I was working to de-uglify one of my GitHub pages (no time to prettify yet), I noticed that, the more fluid I made the layout, the more likely it was that the “Fork me” ribbon would cover up my most visible download buttons.

Obviously, this needs to be fixed, but according to what I could search up, there’s no general solution for clicking through the transparent parts of a PNG. However, given that the ribbon doesn’t necessarily have to be a PNG and that it’s not something like a frame with clear stuff in the center to be clicked through, there may be a specific solution.

None of the ones I’ve found are perfect, but here’s my research so far:

pointer-events

This nifty little property does exactly what I want… but only with an SVG image (For PNGs, it’s an all-or-nothing deal) and it’s apparently only implemented for HTML in Webkit and Gecko-based browsers.

CSS transform

This has actually been done (and since that was written, Opera 10.50 added support for it via the -o- vendor prefix) and you could probably use a polyfill like Transformie or cssSandpaper to make it work on Internet Explorer, but Firefox 6 and below on Linux don’t anti-alias it, so it looks awful. (I haven’t tested Firefox 7+ yet)

CSS clip and border-radius

This is paradoxically the best and worst for graceful degradation, not to mention being a less than ideal solution.If you use clip on your “position: absolute” container to shave off as much whitespace as you can without noticeably affecting the shadow in the PNG, and then use large values of border-radius on the image itself for the bottom-left and top-right corners, you can shave off a pretty respectable amount of the clickable region… but only in Gecko-based browsers (Firefox, SeaMonkey, Fennec, etc.). It turns out that, in other rendering engines, border-radius is a purely visual thing.

Anyway, that’s all I’ve found so far. If anyone has any further suggestions, leave them in the comments and I’ll work them into the post with credit.