Joined: 26 Oct 2012
|Posted: Fri Nov 16, 2012 5:14 am Post subject: RandR multiple monitors and Cinnamon
|These are almost too simple to post (mostly pointing out where some GUI stuff is), but I think they might be useful to have in one place. Plus, there might be someone else like me who would otherwise need a few Google searches before having a "Well, duh!" moment. The following applies to a multiple monitor setup using RandR, with Cinnamon 1.6.
- When setting up a desktop with multiple monitors, remember to set the "xinerama" use flag for the appropriate packages (easiest thing is to just enable it globally). I forgot this when reinstalling and found that, although my desktop still worked, it only could do two things:
- "Mirror" the desktops, so I had two identical displays.
- Treat the entire desktop as if it were one giant screen. This meant that a lot of windows and desktop elements tended to span the dividing line between monitors, which was annoying. Because this sort-of worked, it took me a while to realize that the actual problem was something as basic as not building the GNOME components with proper multi-monitor support.
- As of right now, the GUI interfaces for some basic options are still in the GNOME "Displays" menu, and not "Cinnamon settings". These include resolution and whether to enable "mirroring" of the desktop. A bit less obviously, the colored boxes in the "Displays" menu are actually an interface to RandR. This lets you change the monitors' relative position by dragging them around (e.g. choosing which is on the left and which is on the right, or top/bottom), and also lets you choose the desktop's "primary" monitor. The way to pick the primary monitor is to drag the black bar with the white text to the monitor you want to choose as primary. (This bar is supposed to represent the bar at the top of GNOME 3, but that's less obvious if you've only set this up with Cinnamon, which doesn't have a black bar by default.)
- If you want workspaces to change on only one of your monitors, and the other displays to be static, this is in Cinnamon Settings under "Workspaces" -> "Only use workspaces on primary monitor". This is a bit easier than going into gsettings to set the same option. Unfortunately there doesn't seem to be any intermediate option for setups with three or more monitors (e.g. you can't have one static monitor, while two others use workspaces).
- Setting a desktop wallpaper that spans both screens:
- Go to Cinnamon Settings -> Backgrounds, with "Mode" set to "Wallpaper". (I think this may be the only option right now anyway.)
- Add the wallpaper image you want to use ("+" button).
- Expand "Advanced options" and set "Picture aspect" to "Spanned". This is the only choice that seems to work for multiple monitors, and it "centers" the image without stretching it, so you need to use an image with appropriate dimensions to start with.
- It seems that when you select a new background, you have to change the picture aspect to something else, then switch back to "Spanned". There's apparently a bug in the interface that prevents this setting from taking effect right after you change the background image.