build

docs/dist/xen.js

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+import {Pattern} from "../_snowpack/link/strudel.js";
+import {mod} from "../_snowpack/link/util.js";
+function edo(name) {
+  if (!/^[1-9]+[0-9]*edo$/.test(name)) {
+    throw new Error('not an edo scale: "' + name + '"');
+  }
+  const [_, divisions] = name.match(/^([1-9]+[0-9]*)edo$/);
+  return Array.from({length: divisions}, (_2, i) => Math.pow(2, i / divisions));
+}
+const presets = {
+  "12ji": [1 / 1, 16 / 15, 9 / 8, 6 / 5, 5 / 4, 4 / 3, 45 / 32, 3 / 2, 8 / 5, 5 / 3, 16 / 9, 15 / 8]
+};
+function withBase(freq, scale) {
+  return scale.map((r) => r * freq);
+}
+const defaultBase = 220;
+function getXenScale(scale, indices) {
+  if (typeof scale === "string") {
+    if (/^[1-9]+[0-9]*edo$/.test(scale)) {
+      scale = edo(scale);
+    } else if (presets[scale]) {
+      scale = presets[scale];
+    } else {
+      throw new Error('unknown scale name: "' + scale + '"');
+    }
+  }
+  scale = withBase(defaultBase, scale);
+  if (!indices) {
+    return scale;
+  }
+  return scale.filter((_, i) => indices.includes(i));
+}
+function xenOffset(xenScale, offset, index = 0) {
+  const i = mod(index + offset, xenScale.length);
+  const oct = Math.floor(offset / xenScale.length);
+  return xenScale[i] * Math.pow(2, oct);
+}
+Pattern.prototype._xen = function(scaleNameOrRatios, steps) {
+  return this._asNumber()._withEvent((event) => {
+    const scale = getXenScale(scaleNameOrRatios);
+    steps = steps || scale.length;
+    const frequency = xenOffset(scale, event.value);
+    return event.withValue(() => frequency).setContext({...event.context, type: "frequency"});
+  });
+};
+Pattern.prototype.tuning = function(steps) {
+  return this._asNumber()._withEvent((event) => {
+    const frequency = xenOffset(steps, event.value);
+    return event.withValue(() => frequency).setContext({...event.context, type: "frequency"});
+  });
+};
+Pattern.prototype.define("xen", (scale, pat) => pat.xen(scale), {composable: true, patternified: true});