So,
Using:
Xft.dpi: 220
GDK_SCALE=2
GDK_DPI_SCALE=0.5
QT_AUTO_SCREEN_SCALE_FACTOR=1
xrandr --output DP1 --scale 2x2 --auto --pos 0x0 --primary \
--output eDP1 --scale 1x1 --mode 3840x2160 --pos 5120x0
I noticed that Qt5 apps look now fine on my external screen (Low DPI)
but now super huge on my laptop screen HiDPI.
I think the reason I avoided using QT_AUTO_SCREEN_SCALE_FACTOR and set
that to 0 was because it was being scaled twice (hence the super
hugeness on my laptop) as apparently it looks at the DPI in xrdb, but I
need that for rxvt, i3 etc.
Without doing what you've done and dropping the resolution on my HiDPI
screen. I found this, using:
GDK_SCALE=2
GDK_DPI_SCALE=0.5
QT_AUTO_SCREEN_SCALE_FACTOR=0
QT_SCREEN_SCALE_FACTORS=2
Single Screen Laptop:
xrandr --output eDP1 --scale 1x1 --mode 3840x2160 \
--output DP1 --off
All good.
Single Screen External:
xrandr --output eDP1 --off \
--output DP1 --scale 2x2 --mode 2560x1600
All good.
Both screens!
xrandr --output eDP1 --scale 1x1 --mode 3840x2160 --pos 5120x0 --primary \
--output DP1 --scale 2x2 --mode 2560x1600 --pos 0x0
Small fonts on external screen with Qt5.
xrandr --output eDP1 --scale 1x1 --mode 3840x2160 --pos 5120x0 \
--output DP1 --scale 2x2 --mode 2560x1600 --pos 0x0 --primary
Small fonts on laptop using Qt5. So it seems tied to Primary switch as
to which screen it scales for. Fortunately when using dual monitors I
basically never use virtualbox, wireshark or nvim-qt on the laptop screen.
Incidentally if no primary switch is used the eDP1 becomes primary.
--
Tyler
