Shallow Thoughts : tags : rant

Tricks for Installing a Laser Printer on Linux in CUPS

(Wherein I rant about how bad CUPS has become.)

I had to set up two new printers recently. CUPS hasn't gotten any better since the last time I bought a printer, maybe five years ago; in fact, it's gotten quite a bit worse. I'm amazed at how difficult it was to add these fairly standard laser printers, both of which I'd researched beforehand to make sure they worked with Linux.

It took me about three hours for the first printer. The second one, a few weeks later, "only" took about 45 minutes ... at which point I realized I'd better write everything down so it'll be faster if I need to do it again, or if I get the silly notion that I might want to print from another computer, like my laptop.

I used the CUPS web interface; I didn't try any of the command-line tools.

Figure out the connection type

In the CUPS web interface, after you log in and click on Administration, whether you click on Find New Printers or Add Printer, you're faced with a bunch of identical options with no clue how to choose between them. For example, Find New Printers with a Dell E310dw connected shows:

Available Printers

• [Add This Printer] Virtual Braille BRF Printer (CUPS-BRF)
• [Add This Printer] Dell Printer E310dw (Dell Printer E310dw)
• [Add This Printer] Dell Printer E310dw (Dell Printer E310dw)
• [Add This Printer] Dell Printer E310dw (Dell Printer E310dw (driverless))

What is a normal human supposed to do with this? What's the difference between the three E210dw entries and which one am I supposed to choose? (Skipping ahead: None of them.) And why is it finding a virtual Braille BRF Printer?

The only way to find out the difference is to choose one, click on Next and look carefully at the URL. For the three E310dw options above, that gives:

• dnssd://Dell%20Printer%20E310dw._ipp._tcp.local/?uuid=[long uuid here]
• lpd://DELL316BAA/BINARY_P1
• ipp://DELL316BAA.local:631/ipp/print

Again skipping ahead: none of those are actually right. Go ahead, try all three of them and see. You'll get error messages about empty PPD files. But while you're trying them, write down, for each one, the URL listed as Connection (something like the dnssd:, lpd: or ipp: URLs listed above); and note, in the driver list after you click on your manufacturer, how many entries there are for your printer model, and where they show up in the list. You'll need that information later.

Download some drivers

Muttering about the idiocy of all this -- why ship empty drivers that won't install? Why not just omit drivers if they're not available? Why use the exact same name for three different printer entries and four different driver entries? -- the next step is to download and install the manufacturer's drivers. If you're on anything but Redhat, you'll probably either need to download an RPM and unpack it, or else google for the hidden .deb files that exist on both Dell's and Brother's websites that their sites won't actually find for you.

It might seem like you could just grab the PPD from inside those RPM files and put it wherever CUPS is finding empty ones, but I never got that to work. Much as I dislike installing proprietary .deb files, for both printers that was the only method I found that worked. Both Dell and Brother have two different packages to install. Why two and what's the difference? I don't know.

Once you've installed the printer driver packages, you can go back to the CUPS Add Printer screen. Which hasn't gotten any clearer than before. But for both the Brother and the Dell, ipp: is the only printer protocol that worked. So try each entry until you find the one that starts with ipp:.

Set up an IP address and the correct URL

But wait, you're not done. Because CUPS gives you a URL like ipp://DELL316BAA.local:631/ipp/print, and whatever that .local thing is, it doesn't work. You'll be able to install the printer, but when you try to print to it it fails with "unable to locate printer".

(.local apparently has something to do with assuming you're running a daemon that does "Bonjour", the latest name for the Apple service discovery protocol that was originally called Rendezvous, then renamed to Zeroconf, then to Bonjour. On Linux it's called Avahi, but even with an Avahi daemon this .local thing didn't work for me. At least it made me realize that I had the useless Avahi daemon running, so now I can remove it.).

So go back to Add Printer and click on Internet Printing Protocol (ipp) under Other network printers and click Continue. That takes you to a screen that suggests that you want URLs like:

http://hostname:631/ipp/
http://hostname:631/ipp/port1

ipp://hostname/ipp/
ipp://hostname/ipp/port1

lpd://hostname/queue

socket://hostname
socket://hostname:9100

None of these is actually right. What these printers want -- at least, what both the Brother and the Dell wanted -- was ipp://printerhostname:631/ipp/print

printerhostname? Oh, did I forget to mention static IP? I definitely recommend that you make a static IP for your printer, or at least add it to your router's DHCP list so it always gets the same address. Then you can make an entry in /etc/hosts for printerhostname. I guess that .local thing was supposed to compensate for an address that changes all the time, which might be a nifty idea if it worked, but since it doesn't, make a static IP and use it in your ipp: URL.

Choose a driver

Now, finally! you can move on to choosing a driver. After you pick the manufacturer, you'll be presented with a list that probably includes at least three entries for your printer model. Here's where it helps if you paid attention to how the list looked before you installed the manufacturer's drivers: if there's a new entry for your printer that wasn't there before, that's the non-empty one you want. If there are two or more new entries for your printer that weren't there before, as there were for the Dell ... shrug, all you can do is pick one and hope.

Of course, once you manage to get through configuration to "Printer successfully added", you should immediately run Maintenance->Print Test Page. You may have to power cycle the printer first since it has probably gone to sleep while you were fighting with CUPS.

All this took me maybe three hours the first time, but it only took me about 45 minutes the second time. Hopefully now that I've written this, it'll be much faster next time. At least if I don't succumb to the siren song of thinking a fairly standard laser printer ought to have a driver that's already in CUPS, like they did a decade ago, instead of always needing a download from the manufacturer.

If laser printers are this hard I don't even want to think about what it's like to install a photo printer on Linux these days.

Tags: linux, printing, cups, rant
[ 16:19 Jan 25, 2018    More linux | permalink to this entry | ]

Adding video to an OpenOffice Impress presentation

(and how to convert MPEG video to animated GIF)

I gave an Ignite talk this week at Ignite Silicon Valley. It was a great event! Lots of entertaining talks about all sorts of topics.

I'd always wanted to do an Ignite speech. I always suspected the kicker would be format: O'Reilly's guidelines specified PowerPoint format.

Of course, as a Linux user, my only option for creating PowerPoint slides is OpenOffice. Historically, OpenOffice and I haven't gotten along very well, and this slide show was no exception. Happily, Ignite needs only 20 slides ... how hard can that be, right? Most of my slides were very simple (a few words, or one picture), with one exception: I had one simulation I wanted to show as a video. (When I give this presentation on my own machine, I run the simulation live, but that's not an option on someone else's machine.

Impress woes

First I wrestled with Open Office to create the non-animated slides. It was harder than I'd expected. I just loved having to go back and un-capitalize words that OO kept helpfully re-capitalizing for me. And the way it wouldn't let me change text format on any word that triggered the spellchecker, because it needed to show me the spellcheck context menu instead. And the guessing game clicking around trying to find a place where OO would let me drag to move the text to somewhere where it was approximately centered.

And when I finally thought I had everything, I saved as .ppt, re-loaded and discovered that it had lost all my formatting, so instead of yellow 96 point centered text I had white 14-point left-aligned, and I had to go in and select the text on each slide and change three or four properties on each one.

And I couldn't use it for an actual presentation. In slideshow mode, it only showed the first slide about one time out of six. The other times, it showed a blank slide for the first 15 seconds before auto-advancing to the second one. The auto-advance timing was off anyway (see below). Fortunately, I didn't need use OpenOffice for this presentation; I only needed it to create the PPT file. I ended up making a separate version of the slides in HTML to practice with.

Inserting a movie

But I did eventually have all my static slides ready. It was time to insert my movie, which I had converted to MPEG1 on the theory that it works everywhere. With the mpeg added, I saved one copy to OpenOffice's native format of .odp, plus the .ppt copy I would need for the actual presentation.

Then I quit and opened the .ppt -- and the video slide was blank. A bit of searching revealed that this was a long-known issue, bug 90272, but there seems to be no interest in fixing it. So I was out of luck if I wanted to attach an MPEG, unless I could find someone with a real copy of PowerPoint.

Plan B: Animated GIF

Next idea: convert my 15-second video to an animated GIF. But how to do that? Google found me quite a few web pages that claimed to give the recipe, but they all led to the same error message: ERROR: gif only handles the rgb24 pixel format. Use -pix_fmt rgb24.

So what? Just add -pix_fmt rgb24 to the commandline, right? But the trick turns out to be where to add it, since ffmpeg turns out to be highly picky about its argument order. Here's the working formula to convert a movie to animated GIF:

$ ffmpeg -i foo.mpeg -pix_fmt rgb24 foo.gif

This produced a huge file, though, and it didn't really need to be 1024x768, so I scaled it down with ImageMagick:

convert -depth 8 -scale 800x600 flock-mpeg.gif flock-mpeg-800.gif

which brought the file size from 278M down to a much more reasonable 1.9M.

Happily, OpenOffice does seem to be able to import and save animated GIFs, even to .ppt format. It has trouble displaying them -- that's bug 90272 -- so you wouldn't want to use this format for a presentation you were actually going to give in OpenOffice. But as I mentioned, OpenOffice was already out for that.

If you do this, make sure all your static slides are finished first. Once I loaded the animated GIF, OpenOffice slowed to a crawl and it was hard to do anything at all. Moving text on a slide turned into an ordeal of "hover the mouse where you think a move cursor might show up, and wait 45 seconds ... cursor change? No? Okay, move a few pixels and wait again." Nothing happened in real time. A single mouse click wouldn't register for 30 seconds or more. And this was on my fast dual-core desktop with 4G RAM; I don't even want to think what it would be like on my laptop. I don't know if OOo is running the animations continuously, or what -- but be sure you have everything else finished before you load any animations.

The moment of truth

I never found out whether my presentation worked in real Microsoft Powerpoint. As it turned out, at the real event, the display machine was a Mac running Keynote. Keynote was able to import the .ppt from OpenOffice, and to display the animation. Whew!

One curiosity about the display: the 15 seconds per slide auto-advance failed on the animated slide. The slide showed for 30 seconds rather than 15. I had written this off as another OpenOffice bug, so I wasn't prepared when Keynote did the same thing in the live presentation, and I had to extemporize for 15 seconds.

My theory, thinking about it afterward, is that the presentation programs don't start the counter until the animation has finished playing. So for an Ignite presentation, you might need to set the animation to play for exactly 15 seconds, then set that slide to advance after 0 seconds. If that's even possible.

Or just use HTML. The great irony of this whole story is that some of the other presenters used their own laptops, so I probably could have used my HTML version (which had none of these problems) had I asked. I will definitely remember that for the next Ignite! Meanwhile, I suppose it's good for me to try OO Impress every few years and remind myself why I avoid it the rest of the time.

Tags: speaking, open office, video, rant, flame
[ 16:36 Mar 05, 2010    More speaking | permalink to this entry | ]