Widescreen laptop for presentationsI've written before about how I'd like to get a netbook like an Asus Eee, except that the screen resolution puts me off: no one makes a netbook with vertical resolution of more than 600. Since most projectors prefer 1024x768, I'm wary of buying a laptop that can't display that resolution.
(What was wrong with my beloved old Vaio? Nothing, really, except that the continued march of software bloat means that a machine that can't use more than 256M RAM is hurting when trying to run programs (*cough* Firefox *cough) that start life by grabbing about 90M and goes steadily up from there. I can find lightweight alternatives for nearly everything else, but not for the browser -- Dillo just doesn't cut it.)
Ebay turned out to be the answer: there are lots of subnotebooks there, nice used machines with full displays at netbook prices. And so a month before LCA I landed a nice Vaio TX650 with 1.5G RAM, Pentium M, Intel 915GM graphics and Centrino networking. All nice Linux-supported hardware.
But that raised another issue: how do widescreen laptops (the TX650 is 1366x768) talk to a projector? I knew it was possible -- I see people presenting from widescreen machines all the time -- but nobody ever writes about how it works.
The first step was to get it talking to an external monitor at all. I ran a VGA cable to my monitor, plugged the other end into the Vaio (it's so nice not to need a video dongle!) and booted. Nothing. Hmm.
But after some poking and googling, I learned that with Intel graphics, xrandr is the answer:
xrandr --output VGA --mode 1024x768switches the external VGA signal on, and
xrandr --autoswitches it back off.
Update, April 2010: With Ubuntu Lucid, this has changed and now it's
xrandr --output VGA1 --mode 1024x768
-- in other words, VGA changed to VGA1. You can run
with no arguments to get a list of possible output devices and find
out whether X sees the external projector or screen correctly.
Well, mostly. Sometimes it doesn't work -- like, unfortunately, at the lightning talk session, so I had to give my talk without visuals. I haven't figured that out yet. Does the projector have to be connected before I run xrandr? Should it not be connected until after I've already run xrandr? Once it's failed, it doesn't help to run xrandr again ... but a lot of fiddling and re-plugging the cable and power cycling the projector can sometimes fix the problem, which obviously isn't helpful in a lightning talk situation.
Eventually I'll figure that out and blog it (ideas, anyone?) but the real point of today's article is resolution. What I wanted to know was: what happened to that wide 1366-pixel screen when I was projecting 1024 pixels? Would it show me some horrible elongated interpolated screen? Would it display on the left part of the laptop screen, or the middle part?
The answer, I was happy to learn, is that it does the best thing possible: it sends the leftmost 1024 pixels to the projector, while still showing me all 1366 pixels on the laptop screen.
Why ... that means ... I can write notes for myself, to display in the rightmost 342 screen pixels! All it took was a little bit of CSS hacking in my HTML slide presentation package, and it worked fine. Now I have notes just like my Mac friends with their Powerpoint and their dual-head video cards, only I get to use Linux and HTML. How marvellous! I could get used to this widescreen stuff.
[ 22:12 Feb 06, 2009 More linux/laptop | permalink to this entry | ]