Overhead projected screen shows only wallpaper

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frisket
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Overhead projected screen shows only wallpaper

Post by frisket » Tue Jan 16, 2018 4:16 pm

I took a new Dell XPS 15 into class today to use in teaching. It's running Cinnamon (no MS Windows), and has XFCE and Enlightenment as well. I plugged it into the projector cable, as I have done for years with a variety of other laptops old and new, using the Dell-supplier VGA connector, and the projector picked up the signal OK and displayed...the wallpaper. No icons, no applications, no dock, no shelf, no taskbar, and when I fired up Chromium, it started on the laptop screen but nothing appeared on the projected image. Very pretty wallpaper, but nothing else.

I logged out and switched to the other window managers in turn and got exactly the same results, so it appears to be independent of the WM. I'm not an expert in computer-to-projector connection except that experience shows that projectors are the worst-designed and most obtuse interfaces in existence :-) which is why I was pleasantly surprised that it even recognised the laptop.

But I have no clue why nothing else was visible: I thought the signal sent down a VGA output was a composite video-style signal, in effect a bitmap of the screen, so the projector needs no intelligence, and simply has to reproduce the coloured dots. Clearly I am missing something here, but I don't know what.

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all41
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Re: Overhead projected screen shows only wallpaper

Post by all41 » Tue Jan 16, 2018 4:18 pm

Try this,
Navigate to settings for Display and enable Same image in all monitors
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AndyMH
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Re: Overhead projected screen shows only wallpaper

Post by AndyMH » Tue Jan 16, 2018 5:17 pm

Alternatively, press fn + F7 (or it might be F8 - varies by laptop, look at the little blue icons on the function keys). This will then enable you to toggle between:
  • laptop or projector only
    laptop and projector (same screen)
    projector as an extension to laptop (which is what it sounds like you've got).
If you go for both showing the same screen you will only get the resolution of the lowest res device.
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frisket
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Re: Overhead projected screen shows only wallpaper

Post by frisket » Tue Jan 16, 2018 7:23 pm

Thanks for the suggestions. Unfortunately ‘same in all monitors’ is already enabled, and pressing F8 had no effect.

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