Robotic Tendencies
The personal blog of Robert McQueen

March 21, 2005

GNOME CUPS love?

I was trying to quickly (always a mistake) configure a printer on my (sarge) laptop the other day using GNOME CUPS Manager, which I’d previously been very impressed with when it had Just Worked(tm) on a friend’s Ubuntu box. Unfortunately, it didn’t really work for me, because unlike the one in Ubuntu, didn’t realise I was in the lpadmin group and didn’t need to become root to add a printer, and also unlike the one in Ubuntu, asksed for my root password and not my sudo password, because it or gksu hasn’t been patched, but invoked gksu wrongly, so it didn’t work anyway – I had to use the web interface. I certainly remember that whilst working on a project using GNOME CUPS Manager over the summer, I had to patch it to work with our setup (and not crash if you forget to install the icons *g*). Does anyone except Debian not patch it and expect it to Just Work?

Looking at the Ubuntu package, recognising I’m in the lpadmin group and hence not needing to become root to manipulate the printers is a patch they have applied. It relies on the assumptions that CUPS is running on localhost, and that some bloody-minded admin hasn’t renamed the lpadmin group to something else – these are true on Ubuntu, but not necessarily on any given Debian box. How do we solve this for Debian so our GNOME CUPS Manager Just Works – if the server’s on localhost, read the configuration file to see what the admin group is, or is there a sensible way to find that from the server?

This is probably one of many examples where Debian packages aren’t as usable as the Ubuntu equivalents because Debian users are more likely to challenge the assumptions. Strictly speaking, there shouldn’t need to be this usability gulf between an almost-identical group of packages in Debian and Ubuntu. What’s the right strategy to solve these kinds of problems elsewhere?

As a side note, how is foomatic actually supposed to work if you don’t cheat and install all of the pregenerated PPDs in the foomatic-filters-ppds package?

posted by ramcq @ 2:11 pm
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March 18, 2005

Warped sense of distance

After a very short time at university in Cambridge, doubly so at a college in the centre of town, everyone quickly develops a very warped sense of distance. Anything that takes more than about 10 minutes to walk or 5 minutes to cycle to is Really Far Away, because everything that concerns students in the city is so centralised. Nothing highlights this more than the ongoing debate about which of my college’s two “outlying” undergraduate hostels are further away from college – the one I currently live in, or the one I was in last year. Both have proved to be sufficiently far away from the center of town to cause people who live in college to not bother to come and visit on occasion, or go back home rather than trekking to join us for a further drink. A quick check on Map24 in indicates that they are both in fact the same distance from college – a mere 0.35 miles. 😛

posted by ramcq @ 4:03 am
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March 18, 2005

Beer, Ubuntu love, project stress

Although I was still feeling pretty ill yesterday, I went out last night for a few pints with mjg59 and robsterat the Free Press in Cambridge, a nice non-smoking pub with a few Greene King ales and some interesting trinkets on the wall. Despite having been there several times with Debian folks, and it being just over half a mile from where I currently live, I always have to walk round the wrong way and find the other three pubs in the vicinity before I manag to find it again. Thankfully, on the way back from there to my place to sample some gin and horrible cheap vodka, mjg59 showed me the correct unmarked lane to get directly between the pub and the main road, betraying the fact he’s been in Cambridge for far too long (although in his defence he has lived in the area)…

Later on, as an acid test for Matthew’s ACPI work, we tried installing the Ubuntu Hoary Preview on my really appallingly crappy FIC Celeron 366 old laptop, which previously under Linux did things like never enabling the CPU fan, so hard locking intermittently, and suspending to disk (with APM) when the battery was low, even though the AC was plugged in. It’s also got a really dodgy LCD (not TFT) screen with burnt patches, and weighs a ton. It took quite a while for Ubuntu to install, but booted in pretty decent time after that thanks to magic readahead and hotplug tweaks, and to my absolute amazement actually hibernated and resumed correctly, and suspend to RAM worked too when we enabled it. The CPU fan came on at 55C after making it do some work too, although the GNOME battery applet didn’t seem to notice when it was taken off AC, and lifting the lid doesn’t send a wake-up event like it claims to. Even so, I’m still glad I bought an X40, which is about half the weight and a hell of a lot quicker, and I’ve upgraded the acpi-support packages on it to Hoary’s latest versions to sort out some niggles with stuff not working after resuming from sleep – need to fiddle with my kernel and get hibernation working too. As a side point, I was also really impressed with the Update Manager & notification applet now included in Hoary – it’s exactly what the people I’ve given Ubuntu to in my building need to remember to install security updates.

Today I caught up quite a bit of sleep and felt a lot better, until I realised I had to go and see my project (I know, it’s fairly crackful…) supervisor and report on my progress this term. Unfortunately, I’m mind-bendingly behind schedule due to essentially having achieved nothing at all for several of the weeks in this term – I was hacking on it beforehand and my last darcs patches were from early February. He really wasn’t happy with me, and it was an awkward half hour or so while I explained how much more needed doing. The frustrating thing is even after I’ve done the coding, I have to write a dissertation, and I get marked for that only, and not the code… Now that lectures have finished, and supervisions are winding down, I’m staying in Cambridge over some of the easter break to try and nail it before next term and exam stress kicks in. Had a few pints in the college bar (lots of St. Patrick’s day drunkards around) and a game of Mao with my friends, and now I’m off to bed…

posted by ramcq @ 3:41 am
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March 16, 2005

Fontconfig fun

As is common when I upgrade fontconfig, all of my fonts changed appearance fairly randomly, using the wrong kind of hinting, selecting the wrong fonts, and generally looking very ugly. The usual problem is that debconf runs and decides something different to how I had it configured before, although I can’t quite see why (possibly related to losing my debconf cache to HDD corruption some time ago…). This time round, after upgrading from 2.2.3 to 2.3.0, I ran dpkg-reconfigure fontconfig and successfuly set it back to native hinting, and things looked roughly like they did before, with one major exception: some websites which requested serif fonts, and had previously used Bitstream Vera Serif, now used some other random font which hinted very badly and gave me coloured fringes, and looked generally horrible. The problem also applied in some cases to other sans and mono fonts on websites too, but not all of them.

After a while of using Firefox’s excellent Web Developer Extension to fiddle with the CSS, reading /etc/fonts/fonts.conf, and stracing firefox to see what fonts it was actually loading, I managed to work out that the change was due to this commit in fontconfig CVS. Rather than the old choice of just looking for Times New Roman to provide Times, Arial to provide Helvetica, and Courier New to provide Courier, the fonts.conf in 2.3.0 binds these to the Postscript Type1 Nimbus family of fonts that come in the gsfonts package, which 2.3.0 is now able to read even without having gsfonts-x11 installed. Previously websites which requested Times, "Times New Roman", serif fell back to Bitstream Vera Serif (I don’t have the Microsoft fonts installed) and looked fine, but now are using Nimbus Roman 9 to provide Times, causing the change in appearance.

My first attempt to fix this was to enable the autohinter on these fonts, rather than relying on the native hinting, which works well for the Bitstream Vera and Microsoft fonts, but not otherwise. It was better, but still not that good… So I just overrode the mapping of Times/Helvetica/Courier with my own mappings to the Bitstream Vera fonts. Which worked brilliantly, you can download my ~/.fonts.conf here. I left the autohinting stuff in because occasionally pango might use a glyph from the Nimbus fonts anyway. It also includes a snippet to put the fixed font back even if you have bitmapped fonts turned off, which dato was asking about in #debian-devel.

Sleeping from 7am to 1pm, and the fact I have no food in my room, cupboard or fridge, is probably not helping my cold, so I still feel utterly terrible… *sniff*

posted by ramcq @ 2:34 pm
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March 16, 2005

First post!

I’ve set up a blog so I can share my thoughts, findings and hacks with the world. Woohoo etc. Unfortunately, I seem to have stayed up all night on IRC and fiddling with this and other things like fonts (more on that later), so it’s now 6am, and the DPL IRC debate is just starting. Given that I came down with a cold today, I’m going to have to resign myself to reading the logs, although its tempting to fiddle with the theme and blog some more…

posted by ramcq @ 6:18 am
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