I have a system 76 Galago Ultra Pro, and 90% of the time it lives on my desk connected to an external monitor. My problem is that the system thinks that my external monitor is much smaller than it is, so it makes everything (fonts, icons, etc) on that screen too big.

Here's a screen shot of what the system thinks my monitors look like:


And here's a photo of the actual set up:


Look at the size of that terminal window on the external! It's unpleasant to use. It looks to me like the system recognises the correct resolution of the external, and can tell that it's significantly smaller than that of the laptop (the external is a few years old), but I'd really like to tell it that the actual size of the monitor is larger. Is there a way to do that?


Things on the external monitor are larger because the pixels on the screen are physically larger.

Most external desktop monitors have a pixel density of around 100 Pixels-Per-Inch (PPI). This means that one inch has 100 pixels going across it. This is pretty small, but many things go much smaller.

Your Galago has a 14.1 inch display running at 1920x1080. This translates to about 156 Pixels per inch. In order to cram more pixels into the same physical space (one inch), the pixels have to be much smaller -- around 50% in this case.

This is what makes everything smaller on the Galago and larger on the external monitor.

The problem lies with the differences between physical screen size and logical screen size. The physical size of the display is pretty simple to visualize; it's just the distance from one corner to the other. The Logical size is the actual screen resolution. So your Galago and a Bonobo Extreme both have the same logical screen size (since they both have the same resolution), despite having wildly different physical sizes.

It's similar to scaling up an image in Gimp, or zooming in in Firefox. The physical size of the image gets larger, while the logical size (the pixel dimensions of the image) stay the same.

Future versions of Ubuntu that use Mir will allow for resolution independence, where the size of objects on the screen aren't determined by the pixel density. They use special Grid Units (GU) to design an application. Then all of the Grid Units get turned into physical pixels by Mir. So this means that if a Grid Unit is an inch wide, and the Unity Launcher is one Grid Unit wide, then it will be one inch wide on both a high-density display (like your Galago's built-in display) and one inch wide on Low-Density Displays (like the external monitor).

(By the way, thanks for ordering a Galago! I work for System76, and it's always fun to see our stuff in the wild!)

  • Great, thanks. So 13.10 uses Mir right? does that mean that the issue should fix itself when I install it? – EddyTheB Oct 10 '13 at 17:43
  • Mir will be available in 13.10, but it won't be default until 14.04 [14.10?] In any case, it still needs work to mature, and on top of that the resolution independence will only be a feature on systems without XMir, as in that case you're still running X. – Ian Santopietro Oct 10 '13 at 17:44

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