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Thread: UHD (4K) + WUXGA monitors + nvidia blob + Plasma = mismatched scale issues?

  1. #11
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    Default Re: UHD (4K) + WUXGA monitors + nvidia blob + Plasma = mismatched scale issues?

    Also, a vertical panel on the right of the older monitor would be scaled and re-positioned to the middle of the screen. I ended up removing it.
    Further on this, in the old scaled down monitor, panels, widgets and wallpapers only appear in the top left 63% of the screen (63% = 1/1.6, the scale down factor).

    Aesthetic solutions were to use a solid background black color or a wallpaper with black background, like openSUSE's green lamp one.

  2. #12
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    Default Re: UHD (4K) + WUXGA monitors + nvidia blob + Plasma = mismatched scale issues?

    For future reference, two options to set VirtualBox for 4K. I use two windows-only structural analysis applications. Their icons scale very differently:

    1) SAP - application icons do scale, although they get somewhat smaller at 4K, but still usable.

    VM configuration>monitor:
    2D and 3D acceleration enabled
    scale factor 100% - this means VBox will map 1 host display pixel to 1 guest display pixel, without scaling, i.e., in windowed mode W7 see the max display res of 3840 x 1953 (1200 less the lines used by openSUSE panel)

    W7 guest:
    display scale 180%. this is set at the custom text size (DPI) option (W7 does not give dpi in dpi, but as a percentage)
    pointer scale set to normal.

    Guest welcome/logon screen text & cursor are small, but readable.

    2) CYPE 3D - icons don't scale at all, are so tiny at 4K as to be unusable.

    VM configuration>monitor:
    2D and 3D acceleration enabled
    scale factor 180% - this is how much VBox will scale down the 4K display resolution for the guest, i.e., 3840/1.8 = 2133 horizontal, etc. In my VM in windowed mode, W7 see the max display res of 2133 x 1085 (less than 2160/1.8 = 1200 due to the lines used by openSUSE panel)

    W7 guest:
    display scale 100% (same as standard dpi, only W7 does not give dpi in dpi, but as a percentage)
    pointer scale set to extra large.

    Application icons and guest welcome/logon screen text & cursor are normal size.

    Some unusual scale settings like 157 (VM or guest) will make the mouse very, very laggy, although the guest monitor is at 60Hz, same as the 4K panel.

    Performance does not feel as good as with the first configuration option, but is usable.

  3. #13
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    Default Re: UHD (4K) + WUXGA monitors + nvidia blob + Plasma = mismatched scale issues?

    Quote Originally Posted by brunomcl View Post
    Some unusual scale settings like 157 (VM or guest) will make the mouse very, very laggy, although the guest monitor is at 60Hz, same as the 4K panel.
    Yesterday even with 180% scale factor the VM got insuportably laggy again. Setting it to 200% solved it, I didn't try other scales.

  4. #14
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    Default Re: UHD (4K) + WUXGA monitors + nvidia blob + Plasma = mismatched scale issues?

    Quote Originally Posted by brunomcl View Post
    Yesterday even with 180% scale factor the VM got insuportably laggy again. Setting it to 200% solved it, I didn't try other scales.
    200% is integer scaling (X2), more efficient than floating point (180% = X1.8).
    Reg. Linux User #211409 *** multibooting since 1992
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  5. #15
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    Default Re: UHD (4K) + WUXGA monitors + nvidia blob + Plasma = mismatched scale issues?

    Quote Originally Posted by mrmazda View Post
    200% is integer scaling (X2), more efficient than floating point (180% = X1.8).
    Yes, I'm aware of that. My feeling was that at 180% performance was OK, but on further testing it does carry a penalty. I tested again just now, and at 180% the desktop was perceptibly slower, although much less than the last time. For example, at the first run there was no unusual CPU usage, then the second time virtualbox was using maybe half a core just to keep the display updated. Anyway, from now on I'll use 200%.

    Now I'm trying to deal with the real tiny fonts on some native java apps. Their size seem to be hardcoded. There is still some way to go to make 4K work OOTB on openSUSE. Perhaps when Wayland goes mainstream (if ever) :-)

  6. #16
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    Default Re: UHD (4K) + WUXGA monitors + nvidia blob + Plasma = mismatched scale issues?

    Quote Originally Posted by brunomcl View Post
    Now I'm trying to deal with the real tiny fonts on some native java apps. Their size seem to be hardcoded.
    I think that's a Java "feature". Every time I've tried to use a Java app, I've been unable to make its fonts bigger than the smallest size the OS or DE is capable of rendering, usually 1/4 the size or smaller than what I need, thus making the Java app useless regardless of the screen density or resolution.
    Reg. Linux User #211409 *** multibooting since 1992
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  7. #17
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    Default Re: UHD (4K) + WUXGA monitors + nvidia blob + Plasma = mismatched scale issues?

    The support for PDFStudio, an excellent - for my needs - paid app, had no solution either. They suggested changing the DM from sddm (I run PLasma) to gdm - no joy. Also to use gtk+ theme, but the theme selector in PDFStudio settings only list nimbus and Metal. And this last one, twice...

    They passed the issue to their developers, but don't expect a fast solution.

    My workaround for now is to use a second small script to turn scaling off on the second monitor:
    Code:
    #!/bin/bash
    xrandr --output HDMI-0 --scale 1.0x1.0
    (note that I moved the 4K display to DisplayPort and the WUXGA one to HDMI)

    Now if I want to use a java app I "unscale" the second display and open the app there. After using the app I "rescale" it with:
    Code:
    #!/bin/bash
    xrandr --output HDMI-0 --scale 1.6x1.6

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