fix-dpi: Better GTK+ support

3 files changed, 183 insertions, 55 deletions

diff --git a/.config/bash/rc.d/95_gtk3.sh b/.config/bash/rc.d/95_gtk3.sh
new file mode 100644
index 0000000..99ed337
--- /dev/null
+++ b/.config/bash/rc.d/95_gtk3.sh
@@ -0,0 +1,9 @@
+#!/hint/bash
+
+_gtk_set_shell_DPI() {
+	if [[ -n $DISPLAY ]]; then
+		eval "$(systemctl --user show-environment | grep -e ^GDK_SCALE= -e ^GDK_DPI_SCALE=)"
+		export GDK_SCALE GDK_DPI_SCALE
+	fi
+}
+PROMPT_COMMAND+='_gtk_set_shell_DPI;'
diff --git a/.local/bin/fix-dpi b/.local/bin/fix-dpi
index ee0412d..b700ea9 100755
--- a/.local/bin/fix-dpi
+++ b/.local/bin/fix-dpi
@@ -1,69 +1,146 @@
 #!/usr/bin/env bash
 # Copyright 2019  Luke Shumaker
-#
-# Adjusts the xrandr 1.2, xrandr 1.3, and xrdb DPI settings according
-# to each output's current mode (pixel resolution) and self-reported
-# physical dimensions (mm).
-
-# env-var: MAX_DPI: integer
-# env-var: DRY_RUN: empty=false / non-empty=true
-
-( # Phase 1: Probe outputs
-	export LC_ALL=C
-	xrandr | sed -rn -e 's@(.*) connected( .*)? ([0-9]+)x([0-9]+)\+([0-9]+)\+([0-9]+)( .*)? ([0-9]+)mm x ([0-9]+)mm( .*)?@\1 \3 \4 \8 \9@p' -e 's@^   ([0-9]+)x([0-9]+)i? .*\*.*@ \1 \2@p' | sed '/^\S/{ N; s/\n//; }'
-	#                      1             2      3        4         5         6       7      8            9         10                                 1        2
-	#                      `-outputName  |      `-fb_xpx `-fb_ypx  `-fb_xoff `-fb_yoff      `- hw_xmm    `- hw_ymm |                                  `-hw_xpx `-hw_ypx
-	#                                    `-discard                                  `- discard                     `- discard
-) | ( # Phase 2: Translate that to a set of actions to perform
-	max_xdpi=${MAX_DPI:-96}
-	max_ydpi=${MAX_DPI:-96}
-
-	dpi=$(xrdb -query|sed -n 's/^Xft\.dpi:\s*//p')
-	xdpi=${dpi%%x*}
-	ydpi=${dpi#*x}
-	if (( xdpi > max_xdpi )); then
-		max_xdpi=$xdpi
-	fi
-	if (( ydpi > max_ydpi )); then
-		max_ydpi=$ydpi
+
+sanitize() {
+	[[ $? == 0 ]] || return $?
+	printf '%g\n' "$@"
+}
+
+calc() {
+	[[ $? == 0 ]] || return $?
+	sanitize "$(bc <<<"scale=6; $1")"
+}
+
+round() {
+	[[ $? == 0 ]] || return $?
+	printf '%.f\n' "$@"
+}
+
+roundup_by() {
+	[[ $? == 0 ]] || return $?
+	awk -v by="$2" 'function ceil(x) { return (x == int(x)) ? x : int(x)+1 } { print ceil($1/96)*96 }' <<<"$1"
+}
+
+max() {
+	[[ $? == 0 ]] || return $?
+	awk -v a="$1" -v b="$2" '{ print (a > b) ? a : b }' <<<''
+}
+
+errusage() {
+	if (( $# > 0 )); then
+		printf '%s: %s\n' "${0##*/}" "$(printf "$@")" >&2
 	fi
+	printf "Try '%s --help' for more information.\n" "${0##*/}" >&2
+	exit 2
+}
 
-	declare -A outputs
-	while read -r output fb_xpx fb_ypx hw_xmm hw_ymm hw_xpx hw_ypx; do
-		hw_xdpi=$(bc <<<"($hw_xpx*25.4)/$hw_xmm")
-		hw_ydpi=$(bc <<<"($hw_ypx*25.4)/$hw_ymm")
+usage() {
+	printf 'Usage: %s [OPTIONS]\n' "${0##*/}"
+	printf "Adjust DPI settings to reflect each output's current mode\n"
+	printf "(pixel resolution) and self-reported physical dimensions (mm).\n"
+	echo
+	printf 'OPTIONS:\n'
+	printf '  -h, --help      Show this message\n'
+	printf '  -n, --dry-run   Print what would be done, without doing it\n'
+	printf '  --render-dpi=<auto|auto-hwonly|DPI|XDPIxYDPI>\n'
+	printf '                  Specify what DPI applications should render\n'
+	printf '                  at (default: auto)\n'
+}
 
-		fb_xdpi=$(bc <<<"($fb_xpx*25.4)/$hw_xmm")
-		fb_ydpi=$(bc <<<"($fb_ypx*25.4)/$hw_ymm")
+set -euE -o pipefail
+args=$(getopt -n "${0##*/}" -o 'hn' -l 'help,dry-run,render-dpi:' -- "$@") || errusage
+eval "set -- $args"
 
-		if (( hw_xdpi > max_xdpi )); then
-			max_xdpi=$hw_xdpi
-		fi
-		if (( hw_ydpi > max_ydpi )); then
-			max_ydpi=$hw_ydpi
-		fi
+arg_dry_run=false
+arg_render_dpi=auto
+while (( $# > 0 )); do
+	case "$1" in
+		-h|--help)
+			usage
+			exit 0
+			;;
+		-n|--dry-run)
+			arg_dry_run=true
+			shift
+			;;
+		--render-dpi)
+			arg_render_dpi=$2
+			case "$2" in
+				auto|auto-hwonly)
+					arg_render_dpi=$2
+					;;
+				*)
+					if ! arg_render_dpi="$(sanitize "${2%%x*}" 2>/dev/null)x$(sanitize "${2#*x}" 2>/dev/null)"; then
+						errusage 'Invalid --render-dpi=%q' "$2"
+					fi
+					;;
+			esac
+			shift 2
+			;;
+		--)
+			shift
+			break
+			;;
+	esac
+done
+if (( $# > 0 )); then
+	errusage
+fi
 
-		if (( fb_xdpi > max_xdpi )); then
-			max_xdpi=$fb_xdpi
-		fi
-		if (( fb_ydpi > max_ydpi )); then
-			max_ydpi=$fb_ydpi
+dpis="$(get-dpi)"
+
+if [[ $arg_render_dpi == auto ]] || [[ $arg_render_dpi == auto-hwonly ]]; then
+	arg_render_xdpi=96
+	arg_render_ydpi=96
+	while read -r source item dpi; do
+		if [[ $arg_render_dpi == auto-hwonly ]] && [[ $source != X11-RandR-hw ]]; then
+			continue
 		fi
+		arg_render_xdpi=$(max "$(round "${dpi%%x*}")" "$arg_render_xdpi")
+		arg_render_ydpi=$(max "$(round "${dpi#*x}")" "$arg_render_ydpi")
+	done <<<"$dpis"
 
-		outputs["$output"]="$hw_xdpi $hw_ydpi"
-	done
+	# GDK 3 only supports integer up-scale factors, because
+	# they're morons.  Round arg_render_dpi up to a multiple of '96'.
+	arg_render_xdpi=$(roundup_by "$arg_render_xdpi" 96)
+	arg_render_ydpi=$(roundup_by "$arg_render_ydpi" 96)
+else
+	arg_render_xdpi=${arg_render_dpi%%x*}
+	arg_render_ydpi=${arg_render_dpi#*x}
+fi
+
+(
 	echo 'xrandr \'
-	printf '  --dpi %q \\\n' "${max_xdpi}x${max_ydpi}"
-	for output in "${!outputs[@]}"; do
-		read -r xdpi ydpi <<<"${outputs[$output]}"
-		printf '  --output %q --scale %q \\\n' "$output" "$(bc <<<"scale=5; $max_xdpi/$xdpi")x$(bc <<<"scale=5; $max_ydpi/$ydpi")"
-	done
+	printf '  --dpi %q \\\n' "${arg_render_xdpi}x${arg_render_ydpi}"
+	while read -r source item dpi; do
+		if [[ $source != X11-RandR-hw ]]; then
+			continue
+		fi
+		hw_xdpi="$(sanitize "${dpi%%x*}")"
+		hw_ydpi="$(sanitize "${dpi#*x}")"
+
+		fb_xdpi="$(calc "$arg_render_xdpi/$hw_xdpi")"
+		fb_ydpi="$(calc "$arg_render_ydpi/$hw_ydpi")"
+		printf '  --output %q --scale %q \\\n' "$item" "${fb_xdpi}x${fb_ydpi}"
+	done <<<"$dpis"
+
 	echo
-	printf "xrdb -merge <<<'Xft.dpi: %s'\n" "${max_xdpi}x${max_ydpi}"
-) | ( # Phase 3: Apply those actions
-	if [[ -z "$DRY_RUN" ]]; then
-		bash -v
-	else
+
+	printf "xrdb -merge <<<'Xft.dpi: %s'\n" "${arg_render_xdpi}x${arg_render_ydpi}"
+
+	echo
+
+	GDK_SCALE="$(calc "(${arg_render_xdpi}+${arg_render_ydpi})/2 /96")"
+	printf 'export GDK_SCALE=%q\n' "$GDK_SCALE"
+	# You're not "supposed" to set XRDB Xft.dpi if GDK_SCALE is
+	# set.  Undo Xft.dpi for GDK applications.
+	GDK_DPI_SCALE="$(calc "1/$GDK_SCALE")"
+	printf 'export GDK_DPI_SCALE=%q\n' "$GDK_DPI_SCALE"
+	echo systemctl --user import-environment GDK_SCALE GDK_DPI_SCALE
+) | (
+	if $arg_dry_run; then
 		cat
+	else
+		bash -v
 	fi
 )
diff --git a/.local/bin/get-dpi b/.local/bin/get-dpi
new file mode 100755
index 0000000..b9979bd
--- /dev/null
+++ b/.local/bin/get-dpi
@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+# Copyright 2019  Luke Shumaker
+
+sanitize() {
+	printf '%g\n' "$@"
+}
+
+calc() {
+	sanitize "$(bc <<<"scale=6; $1")"
+}
+
+# GDK
+dpi=$(calc "$(sanitize "${GDK_SCALE:-1}") * 96")
+echo environment GDK-widget ${dpi}x${dpi}
+
+dpi=$(calc "$(sanitize "${GDK_DPI_SCALE:-1}") * 96")
+echo environment GDK-text ${dpi}x${dpi}
+
+# Xft
+dpi=$(xrdb -query|sed -n 's/^Xft\.dpi:\s*//p')
+[[ -n "$dpi" ]] || dpi=96x96
+xdpi=$(sanitize "${dpi%%x*}")
+ydpi=$(sanitize "${dpi#*x}")
+echo X11-resources Xft ${xdpi}x${ydpi}
+
+# RandR
+(
+	export LC_ALL=C
+	xrandr | sed -rn -e 's@(.*) connected( .*)? ([0-9]+)x([0-9]+)\+([0-9]+)\+([0-9]+)( .*)? ([0-9]+)mm x ([0-9]+)mm( .*)?@\1 \3 \4 \8 \9@p' -e 's@^   ([0-9]+)x([0-9]+)i? .*\*.*@ \1 \2@p' | sed '/^\S/{ N; s/\n//; }'
+	#                      1             2      3        4         5         6       7      8            9         10                                 1        2
+	#                      `-outputName  |      `-fb_xpx `-fb_ypx  `-fb_xoff `-fb_yoff      `- hw_xmm    `- hw_ymm |                                  `-hw_xpx `-hw_ypx
+	#                                    `-discard                                  `- discard                     `- discard
+) | while read -r output fb_xpx fb_ypx hw_xmm hw_ymm hw_xpx hw_ypx; do
+	hw_xdpi=$(calc "($hw_xpx*25.4)/$hw_xmm")
+	hw_ydpi=$(calc "($hw_ypx*25.4)/$hw_ymm")
+
+	fb_xdpi=$(calc "($fb_xpx*25.4)/$hw_xmm")
+	fb_ydpi=$(calc "($fb_ypx*25.4)/$hw_ymm")
+
+	echo X11-RandR-hw $output ${hw_xdpi}x${hw_ydpi}
+	echo X11-RandR-fb $output ${fb_xdpi}x${fb_ydpi}
+done