From 97c33b7d13eed8b2a6dc650e60c513e464cdae55 Mon Sep 17 00:00:00 2001
From: Paul Mathieu <paul@ponteilla.net>
Date: Sat, 19 Apr 2025 13:48:53 -0700
Subject: [PATCH] Add quarter-comma meantone tuning

---
 index.html | 28 ++++++++--------------------
 index.js   | 30 ++++++++++++++++++------------
 2 files changed, 26 insertions(+), 32 deletions(-)

diff --git a/index.html b/index.html
index a5c6e51..5f41833 100644
--- a/index.html
+++ b/index.html
@@ -39,26 +39,14 @@
         <article>
           <fieldset>
             <legend><small>Tuning</small></legend>
-            <label>
-              <input type="radio" name="tuning" value="equal">
-              Equal temperament
-            </label>
-            <label>
-              <input type="radio" name="tuning" value="5th">
-              Perfect 5th
-            </label>
-            <label>
-              <input type="radio" name="tuning" value="4th">
-              Perfect 4th
-            </label>
-            <label>
-              <input type="radio" name="tuning" value="maj3rd">
-              Perfect major 3rd
-            </label>
-            <label>
-              <input type="radio" name="tuning" value="min3rd">
-              Perfect minor 3rd
-            </label>
+            <select id="tuning">
+                <option value="equal">Equal</option>
+                <option value="perfect-5th">Perfect 5th</option>
+                <option value="lower-5th">Lower 5th</option>
+                <option value="quartmean-5th">Quarter-comma meantone 5th</option>
+                <option value="quartmean-lower-5th">Quarter-comma meantone lower 5th</option>
+                <option value="perfect-3rd">Perfect major 3rd</option>
+            </select>
             <label>
               From:
               <select id="tuning-from"></select>
diff --git a/index.js b/index.js
index c31034a..01652a6 100644
--- a/index.js
+++ b/index.js
@@ -243,10 +243,14 @@ function refreshHolds() {
     }
 }
 
-function tuneFraction(key, fromKey, fraction) {
+function tuneFactor(key, fromKey, factor) {
+    const index = keyIndex(key);
     const fromIndex = keyIndex(fromKey);
-    const freq = frequencies[fromIndex] * fraction;
-    setFrequency(key, freq);
+    if (index > fromIndex) {
+        setFrequency(key, frequencies[fromIndex] * factor);
+    } else {
+        setFrequency(key, frequencies[fromIndex] / factor);
+    }
 }
 
 function tuneEqual(key, fromKey) {
@@ -305,17 +309,19 @@ function setupListeners() {
     document.getElementById('tune').onclick = () => {
         const key = document.getElementById("current-note").innerHTML;
         const fromkey = document.getElementById('tuning-from').value;
-        const method = radioValue('tuning');
+        const method = document.getElementById('tuning').value;
         if (method === 'equal') {
             tuneEqual(key, fromkey);
-        } else if (method === '5th') {
-            tuneFraction(key, fromkey, 3/2);
-        } else if (method === '4th') {
-            tuneFraction(key, fromkey, 4/3);
-        } else if (method === 'maj3rd') {
-            tuneFraction(key, fromkey, 5/4);
-        } else if (method === 'min3rd') {
-            tuneFraction(key, fromkey, 6/5);
+        } else if (method === 'perfect-5th') {
+            tuneFactor(key, fromkey, 3/2);
+        } else if (method === 'lower-5th') {
+            tuneFactor(key, fromkey, 2/3);
+        } else if (method === 'quartmean-5th') {
+            tuneFactor(key, fromkey, Math.pow(5, 1/4));
+        } else if (method === 'quartmean-lower-5th') {
+            tuneFactor(key, fromkey, Math.pow(5, 1/4));
+        } else if (method === 'perfect-3rd') {
+            tuneFactor(key, fromkey, 5/4);
         }
         refreshHolds();
         updateOptions(key);