get-dpi, fix-dpi: Add EDID overriding and CSS3-based Z-scaling

3 files changed, 100 insertions, 20 deletions

diff --git a/.config/systemd/user/fix-dpi@.service b/.config/systemd/user/fix-dpi@.service
index d248cf2..e5dec6c 100644
--- a/.config/systemd/user/fix-dpi@.service
+++ b/.config/systemd/user/fix-dpi@.service
@@ -8,7 +8,7 @@ Requisite=X11@%i.target
 Environment=DISPLAY=%I
 
 Type=oneshot
-ExecStart=/usr/bin/env flock %t/x11-xrdb@%I -c fix-dpi
+ExecStart=/usr/bin/env flock %t/x11-xrdb@%I fix-dpi --render-dpi=192x192
 SyslogIdentifier=fix-dpi
 
 [Install]
diff --git a/.local/bin/fix-dpi b/.local/bin/fix-dpi
index afcb4a1..0bc5c67 100755
--- a/.local/bin/fix-dpi
+++ b/.local/bin/fix-dpi
@@ -45,18 +45,19 @@ usage() {
 	printf '  --render-dpi=<auto|auto-hwonly|DPI|XDPIxYDPI>\n'
 	printf '                  Specify what DPI applications should render\n'
 	printf '                  at (default: auto)\n'
-	printf '  --device-dpi=OUTPUT=<DPI|XDPIxYDPI>\n'
-	printf '                  Override the hardware-reported DPI for'
-	printf '                  the X11 output OUTPUT\n'
+	printf '  --device-geometry=OUTPUT=<X>x<Y>[x<Z>]\n'
+	printf '                  Override the hardware-reported physical\n'
+	printf '                  dimensions for the X11 output OUTPUT; see\n'
+	printf '                  `get-dpi --help`\n'
 }
 
 set -euE -o pipefail
-args=$(getopt -n "${0##*/}" -o 'hn' -l 'help,dry-run,render-dpi:,device-dpi:' -- "$@") || errusage
+args=$(getopt -n "${0##*/}" -o 'hn' -l 'help,dry-run,render-dpi:,device-geometry:' -- "$@") || errusage
 eval "set -- $args"
 
 arg_dry_run=false
 arg_render_dpi=auto
-declare -A arg_device_dpi
+get_dpi_args=()
 while (( $# > 0 )); do
 	case "$1" in
 		-h|--help)
@@ -81,15 +82,8 @@ while (( $# > 0 )); do
 			esac
 			shift 2
 			;;
-		--device-dpi)
-			if [[ "$2" != *=* ]]; then
-				errusage 'Invalid --device-dpi=%q' "$2"
-			fi
-			device=${2%=*}
-			dpi=${2##*=}
-			if ! arg_device_dpi["$device"]="$(sanitize "${dpi%%x*}" 2>/dev/null)x$(sanitize "${dpi#*x}" 2>/dev/null)"; then
-				errusage 'Invalid --device-dpi=%q' "$2"
-			fi
+		--device-geometry)
+			get_dpi_args+=("$1=$2")
 			shift 2
 			;;
 		--)
@@ -102,7 +96,7 @@ if (( $# > 0 )); then
 	errusage
 fi
 
-dpis="$(get-dpi)"
+dpis="$(get-dpi "${get_dpi_args[@]}")"
 
 if [[ $arg_render_dpi == auto ]] || [[ $arg_render_dpi == auto-hwonly ]]; then
 	arg_render_xdpi=96
@@ -111,9 +105,6 @@ if [[ $arg_render_dpi == auto ]] || [[ $arg_render_dpi == auto-hwonly ]]; then
 		if [[ $arg_render_dpi == auto-hwonly ]] && [[ $source != X11-RandR-hw ]]; then
 			continue
 		fi
-		if [[ $source == X11-RandR-hw ]]; then
-			dpi=${arg_device_dpi["$item"]:-"$dpi"}
-		fi
 		arg_render_xdpi=$(max "$(round "${dpi%%x*}")" "$arg_render_xdpi")
 		arg_render_ydpi=$(max "$(round "${dpi#*x}")" "$arg_render_ydpi")
 	done <<<"$dpis"
@@ -134,7 +125,6 @@ fi
 		if [[ $source != X11-RandR-hw ]]; then
 			continue
 		fi
-		dpi=${arg_device_dpi["$item"]:-"$dpi"}
 		hw_xdpi="$(sanitize "${dpi%%x*}")"
 		hw_ydpi="$(sanitize "${dpi#*x}")"
 
diff --git a/.local/bin/get-dpi b/.local/bin/get-dpi
index 3c9252a..3fba920 100755
--- a/.local/bin/get-dpi
+++ b/.local/bin/get-dpi
@@ -2,13 +2,76 @@
 # Copyright 2019  Luke Shumaker
 
 sanitize() {
+	[[ $? == 0 ]] || return $?
 	printf '%g\n' "$@"
 }
 
 calc() {
+	[[ $? == 0 ]] || return $?
 	sanitize "$(bc <<<"scale=6; $1")"
 }
 
+errusage() {
+	if (( $# > 0 )); then
+		printf '%s: %s\n' "${0##*/}" "$(printf "$@")" >&2
+	fi
+	printf "Try '%s --help' for more information.\n" "${0##*/}" >&2
+	exit 2
+}
+
+usage() {
+	printf 'Usage: %s [OPTIONS]\n' "${0##*/}"
+	printf "Report DPI settings\n"
+	echo
+	printf 'OPTIONS:\n':
+	printf '  -h, --help      Show this message\n'
+	printf '  --device-geometry=OUTPUT=<X>x<Y>[x<Z>]\n'
+	printf '                  Override the hardware-reported physical\n'
+	printf '                  dimensions for the X11 output OUTPUT; X, Y,\n'
+	printf '                  and Z must either have a suffix of "in" or\n'
+	printf '                  "mm", or be "auto"; providing Z causes the\n'
+	printf '                  the dimensions to be scaled to a reference\n'
+	printf '                  viewing distance of 28in (as described in\n'
+	printf '                  [CSS3-values])\n'
+	echo
+	printf '[CSS3-values]: https://www.w3.org/TR/css3-values/#reference-pixel\n'
+}
+
+set -euE -o pipefail
+args=$(getopt -n "${0##*/}" -o 'hn' -l 'help,device-geometry:' -- "$@") || errusage
+eval "set -- $args"
+
+declare -A arg_device_geometry
+while (( $# > 0 )); do
+	case "$1" in
+		-h|--help)
+			usage
+			exit 0
+			;;
+		--device-geometry)
+			if [[ "$2" != *=* ]]; then
+				errusage 'Invalid --device-geometry=%q' "$2"
+			fi
+			device=${2%=*}
+			geometry=${2##*=}
+			re_dim='([0-9]+(.[0-9]+)?(in|mm)|auto)'
+			re_geo="^${re_dim}x${re_dim}(x${re_dim})?\$"
+			if ! [[ "$geometry" =~ $re_geo ]]; then
+				errusage 'Invalid --device-geometry=%q' "$2"
+			fi
+			arg_device_geometry["$device"]=$geometry
+			shift 2
+			;;
+		--)
+			shift
+			break
+			;;
+	esac
+done
+if (( $# > 0 )); then
+	errusage
+fi
+
 # Xft
 dpi=$(xrdb -query|sed -n 's/^Xft\.dpi:\s*//p')
 [[ -n "$dpi" ]] || dpi=96x96
@@ -33,6 +96,33 @@ echo environment+X11-resources GDK-text ${dpi}x${dpi}
 	#                      `-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
+	if [[ -n "${arg_device_geometry["$output"]:-}" ]]; then
+		IFS=x read override_x override_y override_z <<<"${arg_device_geometry["$output"]}"
+		case "$override_x" in
+			*mm) override_xmm="$(sanitize "${override_x%mm}")";;
+			*in) override_xmm="$(calc "$(sanitize "${override_x%in}")*25.4")";;
+			auto) override_xmm="$hw_xmm";;
+		esac
+		case "$override_y" in
+			*mm) override_ymm="$(sanitize "${override_y%mm}")";;
+			*in) override_ymm="$(calc "$(sanitize "${override_y%in}")*25.4")";;
+			auto) override_ymm="$hw_ymm";;
+		esac
+		if [[ "$override_z" == '' ||  "$override_z" == 'auto' ]]; then
+			hw_xmm=$override_xmm
+			hw_ymm=$override_ymm
+		else
+			# algorithm from https://www.w3.org/TR/css3-values/#reference-pixel
+			ref_zmm=711.2 # 28in
+			case "$override_z" in
+				*mm) override_zmm="$(sanitize "${override_z%mm}")";;
+				*in) override_zmm="$(calc "$(sanitize "${override_z%in}")*25.4")";;
+			esac
+			hw_xmm=$(calc "(${override_xmm}*${ref_zmm})/${override_zmm}")
+			hw_ymm=$(calc "(${override_ymm}*${ref_zmm})/${override_zmm}")
+		fi
+	fi
+
 	hw_xdpi=$(calc "($hw_xpx*25.4)/$hw_xmm")
 	hw_ydpi=$(calc "($hw_ypx*25.4)/$hw_ymm")