Xdefaults, xinitrc: dynamically calculate font size

Recent changes in OpenBSD made my laptops share different (althought
correctly calculated) DPIs. Add an script and rework X resources loading
so:

 1. load ~/.Xdefaults into xrdb for baseline
 2. run the script to compute a DPI and xterm's faceSize so it respects
    some values previously defined in this repo

As an upside, now XTerm.VT100.faceSize can be queried, so use that in
hlwm theme.

dotfiles/Xdefaults

@@ -38,20 +38,13 @@ XTerm.VT100.scrollKey:		true
 !XTerm.VT100.wideFont:		-misc-fixed-medium-r-normal--14-130-75-75-c-140-jisx0208.1983-0
 XTerm.VT100.faceName:		monospace
 !XTerm.VT100.faceNameDoublesize:	M+ 1m
-!XTerm.VT100.faceSize:		10.5
+XTerm.VT100.faceSize:		10.5
-!XTerm.VT100.faceSize1:		6.0
+XTerm.VT100.faceSize1:		6.0
-!XTerm.VT100.faceSize2:		8.0
+XTerm.VT100.faceSize2:		8.0
-!XTerm.VT100.faceSize3:		9.0
+XTerm.VT100.faceSize3:		9.0
-!XTerm.VT100.faceSize4:		10.5
+XTerm.VT100.faceSize4:		10.5
-!XTerm.VT100.faceSize5:		12.0
+XTerm.VT100.faceSize5:		12.0
-!XTerm.VT100.faceSize6:		18.0
+XTerm.VT100.faceSize6:		18.0
-XTerm.VT100.faceSize:		8.0
-XTerm.VT100.faceSize1:		4.0
-XTerm.VT100.faceSize2:		6.0
-XTerm.VT100.faceSize3:		7.0
-XTerm.VT100.faceSize4:		8.0
-XTerm.VT100.faceSize5:		10.0
-XTerm.VT100.faceSize6:		12.0
 
 XTerm.VT100.color0:	#000000
 XTerm.VT100.color1:	#872011

dotfiles/xinitrc

@@ -1,6 +1,6 @@
 #!/bin/sh
 # env
-# Written in 2019,2021 by Lucas
+# Written in 2019,2021-2022 by Lucas
 # CC0 1.0 Universal/Public domain - No rights reserved
 #
 # To the extent possible under law, the author(s) have dedicated all
@@ -21,9 +21,13 @@ xset r rate 300 75
 
 xset b off
 
+xrdb -load ~/.Xdefaults
 if [ -r ~/.Xresources ]; then
 	xrdb -merge ~/.Xresources
 fi
+if [ -r ~/code/lucas/env/utils/scripts/x-dpi-facesizes.sh ]; then
+	sh ~/code/lucas/env/utils/scripts/x-dpi-facesizes.sh
+fi
 
 : ${logdir:=~/local/var/log}
 exec herbstluftwm -l >"$logdir/hlwm.out" 2>"$logdir/hlwm.err"

utils/scripts/x-dpi-facesizes.sh

@@ -0,0 +1,53 @@
+#!/bin/sh
+# env
+# Written in 2022 by Lucas
+# CC0 1.0 Universal/Public domain - No rights reserved
+#
+# To the extent possible under law, the author(s) have dedicated all
+# copyright and related and neighboring rights to this software to the
+# public domain worldwide. This software is distributed without any
+# warranty. You should have received a copy of the CC0 Public Domain
+# Dedication along with this software. If not, see
+# <http://creativecommons.org/publicdomain/zero/1.0/>.
+
+FACESIZES="10.5 6.0 8.0 9.0 10.5 12.0 18.0"
+BASEDPI=96
+
+targetdpi=96
+if command -v xdpyinfo >/dev/null 2>&1; then
+	targetdpi=$(xdpyinfo | grep '^  resolution:' | {
+		min=
+		while read -r line; do
+			set -- $line
+			dpi_x=${2%%x*}
+			dpi_y=${2##*x}
+			dpi_sum=$(( $dpi_x + $dpi_y ))
+			if [ -z "$min" ]; then
+				min=$dpi_sum
+			else
+				min=$(( $dpi_sum < $min ? $dpi_sum : $dpi ))
+			fi
+		done
+
+		if [ -z "$min" ]; then
+			echo 96
+		else
+			echo "$min / 2" | bc -l
+		fi
+	})
+fi
+
+for facesize in $FACESIZES; do
+	echo "$BASEDPI * $facesize / $targetdpi"
+done | bc -l | {
+	i=0
+	printf "Xft.dpi:\t%.1f\n" "$targetdpi"
+	while read -r v; do
+		if [ $i -eq 0 ]; then
+			printf "XTerm.VT100.faceSize:\t%.1f\n" "$v"
+		else
+			printf "XTerm.VT100.faceSize%d:\t%.1f\n" $i "$v"
+		fi
+		i=$(($i + 1))
+	done
+} | xrdb -merge

xdg-config-dir/herbstluftwm/theme

@@ -29,7 +29,9 @@
 : ${hlwm_foreground="#fff8f0"}
 
 : ${hlwm_font="-misc-fixed-medium-r-normal--14-130-75-75-c-70-iso10646-1"}
-#: ${hlwm_face="monospace:size=10.5"}
+
-: ${hlwm_face="monospace:size=8.0"}
+_hlwm_faceSize=$(xrdb -get XTerm.VT100.faceSize)
+: ${hlwm_face="monospace:size=${_hlwm_faceSize:-10.5}"}
+unset _hlwm_faceSize
 
 : ${hlwm_font_height=17}