[SOLVED]Global scale and DPI problem on KDE

nurali · 2022-12-06 14:48:26

Hey everyone:
I am using a laptop with 15.6 inch screen,1920x1080 resolution.
And I am using KDE on Xorg session.
Here is the problem,the default DPI was 96,and default global scale was 100%,but I can't see words very clearly in some pages,especially in web browser.
So I changed the scale to 125%,which is the same scale with windows,but it did not fixed the problem,so I did some research on it,I saw an article,got a formula to calculate my DPI,I did the calculation,got my DPI 112.97,so I changed the DPI again,into 113 with 125% global scale,but did't work.

[ali@arch ~]$ cat .Xresources 
Xft.dpi: 113

[ali@arch ~]$ xdpyinfo | grep -B2 resolution
screen #0:
  dimensions:    1920x1080 pixels (508x285 millimeters)
  resolution:    96x96 dots per inch

Need help,thank you all

Last edited by nurali (2022-12-06 16:07:25)

d.ALT · 2022-12-06 14:52:13

I don't remeber if nowadays Plasma is capable of Fractional Scaling... Anyway, could you have a look at this?: https://wiki.archlinux.org/title/HiDPI#KDE_Plasma

V1del · 2022-12-06 14:59:41

You'll want to set the DPI of the server itself as well: https://wiki.archlinux.org/title/Xorg#D … ze_and_DPI

nurali · 2022-12-06 15:01:17

d.ALT wrote:

I don't remeber if nowadays Plasma is capable of Fractional Scaling... Anyway, could you have a look at this?: https://wiki.archlinux.org/title/HiDPI#KDE_Plasma

Thanks for replying,I have read that,I don't very understand,what is "desired size"?It showing unclear fonts with the defaults,how should I get the "desired size" to drag it?
Teach me plz if you know something about that

nurali · 2022-12-06 15:02:33

V1del wrote:

You'll want to set the DPI of the server itself as well: https://wiki.archlinux.org/title/Xorg#D … ze_and_DPI

Thanks for replying,I'll take a look at that

nurali · 2022-12-06 15:50:41

V1del wrote:

You'll want to set the DPI of the server itself as well: https://wiki.archlinux.org/title/Xorg#D … ze_and_DPI

Section "Monitor"
    Identifier             "eDP"
    DisplaySize             345 194    # In millimeters
EndSection

After I write this,96x96 changed into

[ali@arch ~]$ xdpyinfo | grep -B2 resolution
screen #0:
  dimensions:    1920x1080 pixels (345x194 millimeters)
  resolution:    141x141 dots per inch

I call it a success,thank you!
Solved most of the problem,and could you please tell me what size I should set to DPI when I use 125% scale?
I am little bit confused by connection of those things

Last edited by nurali (2022-12-06 15:53:24)

V1del · 2022-12-07 09:57:41

Up to you. Configuring the DPI correctly (according to the size of the monitor) should lead to an improvement across the board without explicitly scaling additionally but if you feel elements are still to small you can relevantly bump things a bit by scaling things up additionally.

cfr · 2022-12-10 01:45:44

In my experience, it's better to change as little as possible through KDE systemsettings, but you do have to play around somewhat, especially if you use both QT and GTK applications as they can pull in opposite directions.

My DPI works out to 176x176. I don't force font DPI in KDE settings, though I do check anti-aliasing. I use sddm and set QT's high-DPI scaling to true. I then use very small fonts in KDE settings (6 and 7pt). I used to set scaling separately for GTK applications and use larger fonts, but I don't seem to be doing that any longer.

I am not claiming this is an especially good way to do it. Just that it works reasonably well for me. What's odd is that some things still come up too big and others too small. So a certainly amount of bespoke fiddling still seems required, but it is getting better, I think.

nurali · 2022-12-10 02:00:12

cfr wrote:

In my experience, it's better to change as little as possible through KDE systemsettings, but you do have to play around somewhat, especially if you use both QT and GTK applications as they can pull in opposite directions.
My DPI works out to 176x176. I don't force font DPI in KDE settings, though I do check anti-aliasing. I use sddm and set QT's high-DPI scaling to true. I then use very small fonts in KDE settings (6 and 7pt). I used to set scaling separately for GTK applications and use larger fonts, but I don't seem to be doing that any longer.
I am not claiming this is an especially good way to do it. Just that it works reasonably well for me. What's odd is that some things still come up too big and others too small. So a certainly amount of bespoke fiddling still seems required, but it is getting better, I think.

Thanks for your advice
I found that my true DPI is 142×141，I'm going to try that.
There is a weird thing happened,when global scale set to 100%，xrandr outputs correct display size(by mm),but when it go to 125%,xrandr shows an odd display size.
I don't know what is the commection between global scale and dpi,I am preparing to leave scale with 100%,just change dpi.

cfr · 2022-12-10 03:13:19

As V1del said, you will probably have better luck keep DPI matching your actual DPI and scaling if required. My DPI is higher than yours because I have a screen with the same resolution which is physically smaller. That is, I have 1920x1080 pixels in a 12.5" screen. So my native DPI is going to be higher than yours. But the general principle of sticking with a DPI which matches your display's DPI is likely to be better in both cases i.e. you'll get better results at 141 and I'll get better results at 176.

nurali · 2022-12-10 03:15:47

cfr wrote:

As V1del said, you will probably have better luck keep DPI matching your actual DPI and scaling if required. My DPI is higher than yours because I have a screen with the same resolution which is physically smaller. That is, I have 1920x1080 pixels in a 12.5" screen. So my native DPI is going to be higher than yours. But the general principle of sticking with a DPI which matches your display's DPI is likely to be better in both cases i.e. you'll get better results at 141 and I'll get better results at 176.

OK,thans for explaining,it is understandable

Arch Linux

#1 2022-12-06 14:48:26

[SOLVED]Global scale and DPI problem on KDE

#2 2022-12-06 14:52:13

Re: [SOLVED]Global scale and DPI problem on KDE

#3 2022-12-06 14:59:41

Re: [SOLVED]Global scale and DPI problem on KDE

#4 2022-12-06 15:01:17

Re: [SOLVED]Global scale and DPI problem on KDE

#5 2022-12-06 15:02:33

Re: [SOLVED]Global scale and DPI problem on KDE

#6 2022-12-06 15:50:41

Re: [SOLVED]Global scale and DPI problem on KDE

#7 2022-12-07 09:57:41

Re: [SOLVED]Global scale and DPI problem on KDE

#8 2022-12-10 01:45:44

Re: [SOLVED]Global scale and DPI problem on KDE

#9 2022-12-10 02:00:12

Re: [SOLVED]Global scale and DPI problem on KDE

#10 2022-12-10 03:13:19

Re: [SOLVED]Global scale and DPI problem on KDE

#11 2022-12-10 03:15:47

Re: [SOLVED]Global scale and DPI problem on KDE

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