Hi Tyler, I did a lot of experimenting a while back to find something that works well for me. I have a MacBook Pro with a HiDPI screen connected to two 1080p external monitors via ThunderBolt-to-DisplayPort adapters. I place my MacBook Pro to the right of the two external monitors. I also run i3. Here's what I found worked for me: .Xresources contains: Xft.dpi: 220 .xinitrc contains: xrdb -merge ~/.Xresources export QT_AUTO_SCREEN_SCALE_FACTOR=1 export GDK_SCALE=1.5 export GDK_DPI_SCALE=0.75 exec i3 xrandr command for external monitors: xrandr --output DP1 --scale 1.5x1.5 --auto --pos 0x0 --primary --output DP2 --scale 1.5x1.5 --auto --pos 2880x0 --output eDP1 --mode 1920x1200 --pos 5760x0 xrandr command for switching back to internal laptop screen: xrandr --output eDP1 --auto --primary --output DP1 --off --output DP2 --off I tried playing with panning but I found it easier to just set similar resolutions using whatever mode I want on the monitors and the proper scale option and then specifying the absolute positions with --pos. When external monitors are enabled, I reduce the resolution of my laptop screen because the laptop is on a stand further away from me so I need the text a bit larger. Good luck. Let us know how it goes. Thanks, Eric On Mon, Jul 30, 2018 at 11:18 PM Tyler <tylera@xxxxxxxxxxxxxxxxx> wrote: > Hi, > > I am using ArchLinux with i3 on my Dell XPS 13" 9370 @ 3840x2160) HiDPI > and everything works great with: > > .Xresources: > > ! xft fonts > !---------------------------------------------------------------------- > Xft.dpi: 220 > Xft.autohint: 0 > Xft.lcdfilter: lcddefault > Xft.hintstyle: hintfull > Xft.hinting: 1 > Xft.antialias: 1 > Xft.rgba: rgb > > ! urxvt > !--------------------------------------------------------------------- > URxvt*font: xft:DejaVu Sans Mono for Powerline:size=12: \ > minspace=False:antialias=true, \ > xft:Segoe UI Emoji:size=12:minspace=False:antialias=true > > URxvt*boldFont: xft:DejaVu Sans Mono for Powerline:size=12: \ > minspace=False:antialias=true, \ > xft:Segoe UI Emoji:size=12:minspace=False:antialias=true > > URxvt.letterSpace: -1 > > > > and in /etc/profile.d/hidpi.sh > > export GDK_SCALE=2 > export GDK_DPI_SCALE=0.5 > export QT_AUTO_SCREEN_SCALE_FACTOR=0 > export QT_SCREEN_SCALE_FACTORS=2 > export QT_QPA_PLATFORMTHEME=qt5ct > > > > However recently I bought a Dell DA300 Mobile Adapter and decided I > wanted to use my external Dell 30" 3000WFP (2560x1600) over DisplayPort. > > I found this blog article > https://blog.summercat.com/configuring-mixed-dpi-monitors-with-xrandr.html > which explains exactly what I am trying to do. The only difference is > the placement of the external screen (mine is on the left of the laptop) > and the screen size and resolution. > > In that article he uses his HiDPI on both screens and then scales down > on the external screen, which is why he doubles the resolution of the > external display. The reason he does that is so he doesn't have to touch > .Xresources or fiddle with toolkit scaling options. > > Using this command I was able to get it working great with a single > external monitor ie the Dell 30" 3000WFP @ (2560x1600) > > xrandr --dpi 220 --fb 5120x3200 \ > --output eDP1 --off \ > --output DP1 --scale 2x2 --panning 5120x3200 > > With the dual-monitor setup I'm struggling to understand the panning > option. I have looked at https://wiki.archlinux.org/index.php/xrandr and > the man file and still couldn't figure that track x track y part out. > It's not very easy to understand. > > So far for the external monitor I have this: > > xrandr --dpi 220 --fb 8960x5360 \ > --output eDP1 --mode 3840x2160 \ > --output DP1 --scale 2x2 --pos -2560x0 --panning 5120x3200+2560+0 > > What I want is to be able to access the whole area of both screens. In > his example he has a laptop at 3200x1800 and an external monitor at > 1920x1080 > > > Dual monitors > > > > When I want to use both monitors, this is the command I run: > > > > xrandr --dpi 276 --fb 7040x3960 \ > > --output eDP-1 --mode 3200x1800 \ > > --output DP-1-2 --scale 2x2 --pos 3200x0 --panning 3840x2160+3200+0 > > > > Here's an explanation of the options: > > > > Global options: > > --dpi 276 sets the DPI to 276. > > --fb 7040x3960 creates one screen with resolution 7040x3960. > This is the combined resolution of the two monitors. The high DPI monitor > has 3200x1800 resolution. The lower DPI monitor has 1920x1080 resolution, > but I double it as I scale it by 2 (see below). Combine these like so: > 3200+1920*2 x 1800+1080*2 = 7040x3960. Both monitors share this screen. > > High DPI monitor options (--output eDP-1): > > --mode 3200x1800 says to use resolution 3200x1800. This is the > default, but specifying it is necessary if the monitor is disabled (as it > is when using the external monitor by itself) as it enables the monitor. > > Lower DPI monitor options (--output DP-1-2): > > --scale 2x2 is similar to zooming out. This is necessary as we > set the DPI globally to that of the high DPI monitor. > > --pos positions it to the right of the laptop monitor. > > --panning allows our pointer to access the whole area. > > Any help or tips would be much appreciated! > > -- > Tyler >
