Cthulhu is no longer a fork. Now it is a screen reader written in Golang.

internal/sound/position.go

@@ -0,0 +1,33 @@
+// Copyright (c) 2026 Storm Dragon
+// Authors: Storm Dragon, Angus Kola
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package sound
+
+import (
+	"math"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const positionCuePrefix = "generated-position-tone:"
+
+// PositionCueName encodes relative position: zero is first, one is last.
+func PositionCueName(position float64) string {
+	return positionCuePrefix + strconv.FormatFloat(position, 'g', -1, 64)
+}
+
+func set_position(cue string) (float64, bool) {
+	if !strings.HasPrefix(cue, positionCuePrefix) {
+		return 0, false
+	}
+	position, err := strconv.ParseFloat(strings.TrimPrefix(cue, positionCuePrefix), 64)
+	return position, err == nil && !math.IsNaN(position) && !math.IsInf(position, 0) && position >= 0 && position <= 1
+}
+
+func position_tone_wav(position float64) []byte {
+	// Two octaves distinguish the ends of a set. Smooth the edges of this
+	// short cue; the service supplies the user's volume and stereo position.
+	return tone_wav(220*math.Pow(4, position), 60*time.Millisecond, 0.5, 5*time.Millisecond)
+}