1 files changed, 62 insertions, 0 deletions
diff --git a/bin/bright b/bin/bright
new file mode 100755
index 0000000..7aa0801
--- /dev/null
+++ b/bin/bright
@@ -0,0 +1,62 @@
+#!/bin/sh
+
+set -eu
+
+get_b()
+{
+	local b=
+
+	b=$(brightnessctl --class=backlight get) || return 1
+	printf '%.0f\n' $(printf \
+		'scale = 4; (7 * sqrt((2 - %d) * (%d - 3102))) / 1550\n' \
+		${b} ${b} | bc)
+
+	return 0
+}
+
+set_b()
+{
+	local b="${1}"
+	shift 1
+
+	brightnessctl --class=backlight set $(printf '%.0f\n' \
+		$(printf 'scale = 4; 2 + (1 - sqrt(1 - (%d / 7)^2)) * 1550\n' \
+		${b} | bc)) || return 1
+
+	return 0
+}
+
+usage()
+{
+	printf 'Usage: %s {-|+}\n' "${0}"
+
+	return 0
+}
+
+main()
+{
+	local dir=
+	local b=
+
+	if [ ${#} -ne 1 ]; then
+		usage 1>&2
+		return 1
+	fi
+	dir="${1}"
+	shift 1
+
+	case "${dir}" in
+		-|+);;
+		*)
+			usage 1>&2
+			return 1
+			;;
+	esac
+
+	b=$(get_b) || return 1
+	set_b $((${b} ${dir} 1)) || return 1
+
+	return 0
+}
+
+main "${@}"