i3 and highdpi / HD dual screens: how to scale properly?

I have two monitors:

DP-1: 1920x1080 (hd, secondary)

eDP-1: 3840x2160 (4k, main)

My problem:

I want to set my 4k monitor to 200% scaling @ 3840x2160, and my HD monitor to 100% scaling @ 1920x1080

What I have attempted:

Running i3, it appears, visually the default setting is to keep everything at 4k @ 1x1 scaling. (When I check arandr it appears the HD monitor is set to 1080 but visually this does not appear to be the case).

In the gnome desktop environment, I must do a bit of trickery to get my two monitors to display properly. I run: xrandr --output eDP-1 --scale 0.999x0.999 --pos 3840x0 ; xrandr --output DP-1 --scale 1.999x1.999 --mode 1920x1080 --fb 7680x2160 --pos 0x0

In Gnome, that works like a charm, but when I run this in i3, it appears to set everything to 3840x2160 @ 100% scaling (very very small). I also get the error:

X Error of failed request:  BadMatch (invalid parameter attributes)
  Major opcode of failed request:  140 (RANDR)
  Minor opcode of failed request:  7 (RRSetScreenSize)
  Serial number of failed request:  33
  Current serial number in output stream:  34

What I've done:

✔️ I can make the HD monitor work as follows: xrandr --output DP-1 --scale 1x1 --mode 1920x1080

Now when I adjust my main 4k monitor, it has the following curious behaviour:

✔️ xrandr --output eDP-1 --mode 3840x2160 adjusts it to the right resolution

❌ xrandr --output eDP-1 --scale 2x2 makes it REALLY small

✔️ xrandr --output eDP-1 --scale 0.5x0.5 makes things the right size, but blurry

❌ xrandr --output --dpi <attempted with value 96, 192> doesn't work and fails with:

X Error of failed request:  BadMatch (invalid parameter attributes)
  Major opcode of failed request:  140 (RANDR)
  Minor opcode of failed request:  7 (RRSetScreenSize)
  Serial number of failed request:  33
  Current serial number in output stream:  35

So I am able to have both monitors at the correct resolutions, but I am unable to have crisp 200% scaling in my 4K monitor. For some reason where I had to do 2x2 scaling in Gnome to make things bigger, I must do 0.5x0.5 scaling in i3 to make things bigger, and this makes it blurry. Edit: oh yeah and although the UI elements are proportional, the mouse is REALLY big

Qua nhiều thế kỷ, tôi đã tìm ra điều này. Giải pháp không phải là áp dụng tỷ lệ 0,5x0,5 mà là điều chỉnh DPI. Tôi không nghĩ rằng các điều chỉnh DPI đang hoạt động vì bạn cần làm mới i3 để xem chúng (Mod+shift+r)

Tôi đã thêm những điều sau đây vào ~/.Xresource:

Xft.dpi: 192

Sau đó tôi chạy các lệnh sau:

xrdb -merge .Xresource

giám đốc điều hành i3

Sau đó, tôi chạy đoạn script sau, mượn từ [bài viết này] [1]:

#!/bin/bash
xrandr --dpi 192 --fb 7680x4320 \
    --output eDP-1 --mode 3840x2160 \
    --output DP-1 --scale 2x2 --pos 3840x0 --panning 3840x2160+3840+0

Sau đó, việc mở rộng quy mô dường như hoạt động! [1]: https://blog.summercat.com/conforming-mixed-dpi-monitor-with-xrandr.html