Re: [gentoo-user] New monitor, new problem. Everything LARGE O_O

[Michael <confabulate@kintzios.com>]

[-- Attachment #1: Type: text/plain, Size: 5148 bytes --]

On Saturday, 6 July 2024 10:59:30 BST Dale wrote:
> Mark Knecht wrote:
> > On Tue, Jul 2, 2024 at 12:44 PM Dale <rdalek1967@gmail.com
> > <mailto:rdalek1967@gmail.com>> wrote:
> > <SNIP>
> > 
> > > I tried it with those options and without.  Neither changed anything.  I
> > > originally tried it with no xorg.conf at all.  I was hoping maybe the
> > > Nvidia GUI thing would adjust things.  I may try that again.  No
> > > xorg.conf and use the GUI thing.  That's what I use to set up my TV and
> > > such anyway.  Thing is, the sddm screen is HUGE too.
> > 
> > <SNIP>
> > 
> > > :-)  :-)
> > 
> > ???
> > 
> > xdpyinfo | grep -B2 resolution
> > 
> > ???
> 
> I booted my new rig up again.  Dang that thing.  It was HUGE again.  I
> started reading stuff, mainly about xorg.conf and the available
> settings.  I changed all sorts of stuff, including some things Micheal
> suggested.  I restarted DM each time.  I was about ready to toss it in
> the old minnow pond, that's where everything goes to die here.  Lots of
> CRT monitors in there.  LOL  Anyway, I had to install that package to
> run that command.  It spit out a oops when I tried to run it after a
> copy and paste.  I also installed it on my main rig, just to compare. 
> On the new rig, the DPI was a fairly large number.  I thought I had the
> output saved but it seems to be gone.  My main rig tho showed 80x80 dots
> per inch.  I did a duck search, finally found how to set that.  I then
> restarted DM and YEPPIE!!!  It was a normal size again. 
> 
> Now the monitor on my main rig is a bit older too.  Maybe 6 or 7
> years???  Should newer monitors be set to a higher number for DPI?  Is
> that normal?  Why was it using such a high number by default?  I want to
> say one was like 200 or something.  It was quite large.  The reason I'm
> asking, I may need to set something else to make the screen the right
> size but let it use that larger dpi number, if that is what the newer
> monitor prefers to use. 
> 
> Now to reboot, see if I have thoughts of that minnow pond again.  :/ 
> 
> Dale
> 
> :-)  :-) 

I'm struggling to follow your post because you do not provide specific 
information on the commands you input, the output you get in your terminal and 
the observed changes in the monitor.

You also don't provide info on the changes you made in your xorg.conf, or 
xrandr and the corresponding changes observed each time in your Xorg.0.log.

Strictly speaking, the pixel density of an on-screen digital image is referred 
to as Pixels Per Inch (PPI), but the term DPI which refers to a printed image 
of ink Dots Per Inch has stuck.

In addition, there is the physical pixel density of your monitor and the 
rendered pixel density of the X11 image(s).  Tweaking the latter allows you to 
scale the display and make images look larger than the native monitor 
resolution.

You can set the DPI in your xorg.conf, or you can set it with xranrd, or you 
can set it on the CLI when you launch X, but usually this is not necessary and 
could mess up the scaling of your fonts, window decorations and symbols too 
(the font DPI is set differently by setting Xft.dpi: in ~/.Xresources, of the 
window manager's/DE font settings).

A good starting point is to get the manual of your monitor and look at its 
published native resolution, e.g. 1920x1080 and the physical monitor size over 
which this resolution is displayed.  Let's assume this 1920x1080 native 
resolution belongs to a 23" monitor.  A 23" diagonal would correspond to a 20" 
wide screen real estate.  Consequently the horizontal PPI would be:

PPI = 1920 pixels / 20" = 96

The same resolution on a 24" wide monitor would give a PPI of:

PPI = 1920 pixels / 24" = 80

Obviously a physically wider 24" monitor with the same native screen 
resolution as a smaller 20" monitor will not look as sharp when viewed from 
the *same* distance.

Similarly, changing the selected resolution on the same 23" monitor from say 
1920 pixels wide to a lower resolution of 1280 pixels gives a PPI of 64.

I leave the calculation of the vertical PPI to the reader.

Usually I start with no xorg.conf and leave the card to detect what the 
monitor prefers, then use the Scale setting in the desktop settings to 
increase/decrease (zoom in/zoom out) the displayed scale.  This has the effect 
of altering the PPI to higher or lower values to improve readability of 
content.  The above should help you arrive at some practical resolution, but I 
would start with the native resolution of the monitor and work down from there 
if you find it difficult to read its display.

NOTE: Using Qt scaling can mess up window decorations, widgets, etc.  I've 
found it doesn't work well with some KDE applications and their menus/
submenus, or pop up windows.  You need to set PLASMA_USE_QT_SCALING=1 to make 
it follow Qt scaling and there's GTK3 too which may need tuning.  This is the 
reason I calculate PPI before I venture into buying a new monitor, unless I 
can see it in person to make sure I can still read its content.  ;-)

[-- Attachment #2: This is a digitally signed message part. --]
[-- Type: application/pgp-signature, Size: 833 bytes --]