Merge pull request 'delta -> tight/tightx/loose refinements' (#1832) from delta into main

Reviewed-on: https://codeberg.org/uzu/strudel/pulls/1832

packages/core/signal.mjs

@@ -970,10 +970,48 @@ export const keyDown = register('keyDown', function (pat) {
 });
 
 /**
- * A pattern that gives the duration of events that are combined with it.
+ * A pattern measuring the duration of events,
+ * in cycles per event. `cyclesPer` doesn't have structure itself, but takes structure, and therefore
+ * event durations, from the pattern that it is combined with.
+ * For example `cyclesPer.struct("1 1 [1 1] 1")` would give the same as `"0.25 0.25 [0.125 0.125] 0.25"`.
+ * See also its reciprocal, `per`, also known as `perCycle`.
  * @example
- * sound("bd sd [bd bd] sd*4 [- sd] [bd [bd bd]]").note(delta.withValue(x => 1/x + 20))
+ * // Shorter events are lower in pitch
+ * sound("saw saw [saw saw] saw")
+ *   .note(cyclesPer.range(50, 100))
+ * @example
+ * sound("bd sd [bd bd] sd*4 [- sd] [bd [bd bd]]")
+ *   .note(cyclesPer.add(20))
  */
-export const delta = new Pattern(function (state) {
+export const cyclesPer = new Pattern(function (state) {
   return [new Hap(undefined, state.span, state.span.duration)];
 });
+
+/**
+ * A pattern measuring the 'shortness' of events, or in other words, the duration of pattern events,
+ * in events per cycle. `per` doesn't have structure itself, but takes structure, and therefore
+ * event durations, from the pattern that it is combined with.
+ * For example `per.struct("1 1 [1 1] 1")` would give the same as `"4 4 [8 8] 4"`.
+ * See also its reciprocal, `cyclesPer`.
+ * @synonyms perCycle
+ * @example
+ * // Shorter events are more distorted
+ * n("0 0*2 0 0*2 0 [0 0 0]@2").sound("bd")
+ *  .distort(per.div(2))
+ */
+export const per = new Pattern(function (state) {
+  return [new Hap(undefined, state.span, Fraction(1).div(state.span.duration))];
+});
+
+export const perCycle = per;
+
+/**
+ * Like `per` but measures the shortness of events according to an exponential curve. In
+ * particular, where the event duration halves, the
+ * returned value increases by one. `perx.struct("1 1 [1 [1 1]] 1")` would therefore be
+ * the same as `"3 3 [4 [5 5]] 3"`.
+ */
+export const perx = new Pattern(function (state) {
+  const n = Fraction(1).div(state.span.duration);
+  return [new Hap(undefined, state.span, Math.log(n) / Math.log(2) + 1)];
+});

packages/core/test/pattern.test.mjs

@@ -740,20 +740,6 @@ describe('Pattern', () => {
       );
     });
   });
-  describe('signal()', () => {
-    it('Can make saw/saw2', () => {
-      expect(saw.struct(true, true, true, true).firstCycle()).toStrictEqual(
-        sequence(0, 1 / 4, 1 / 2, 3 / 4).firstCycle(),
-      );
-
-      expect(saw2.struct(true, true, true, true).firstCycle()).toStrictEqual(sequence(-1, -0.5, 0, 0.5).firstCycle());
-    });
-    it('Can make isaw/isaw2', () => {
-      expect(isaw.struct(true, true, true, true).firstCycle()).toStrictEqual(sequence(1, 0.75, 0.5, 0.25).firstCycle());
-
-      expect(isaw2.struct(true, true, true, true).firstCycle()).toStrictEqual(sequence(1, 0.5, 0, -0.5).firstCycle());
-    });
-  });
   describe('_setContext()', () => {
     it('Can set the hap context', () => {
       expect(

packages/core/test/signal.test.mjs

@@ -0,0 +1,61 @@
+/*
+signal.test.mjs - <short description TODO>
+Copyright (C) 2022 Strudel contributors - see <https://codeberg.org/uzu/strudel/src/branch/main/packages/core/test/pattern.test.mjs>
+This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details. You should have received a copy of the GNU Affero General Public License along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+import Fraction from 'fraction.js';
+
+import { describe, it, expect, vi } from 'vitest';
+
+import { saw, saw2, isaw, isaw2, per, perx, cyclesPer } from '../signal.mjs';
+import { fastcat, sequence, State, TimeSpan, Hap } from '../index.mjs';
+
+const st = (begin, end) => new State(ts(begin, end));
+const ts = (begin, end) => new TimeSpan(Fraction(begin), Fraction(end));
+const hap = (whole, part, value, context = {}) => new Hap(whole, part, value, context);
+
+const third = Fraction(1, 3);
+const twothirds = Fraction(2, 3);
+
+const sameFirst = (a, b) => {
+  return expect(a.sortHapsByPart().firstCycle()).toStrictEqual(b.sortHapsByPart().firstCycle());
+};
+
+describe('signal()', () => {
+  it('Can make saw/saw2', () => {
+    expect(saw.struct(true, true, true, true).firstCycle()).toStrictEqual(
+      sequence(0, 1 / 4, 1 / 2, 3 / 4).firstCycle(),
+    );
+
+    expect(saw2.struct(true, true, true, true).firstCycle()).toStrictEqual(sequence(-1, -0.5, 0, 0.5).firstCycle());
+  });
+  it('Can make isaw/isaw2', () => {
+    expect(isaw.struct(true, true, true, true).firstCycle()).toStrictEqual(sequence(1, 0.75, 0.5, 0.25).firstCycle());
+
+    expect(isaw2.struct(true, true, true, true).firstCycle()).toStrictEqual(sequence(1, 0.5, 0, -0.5).firstCycle());
+  });
+});
+
+describe('cyclesPer', () => {
+  it('gives cycles per hap', () => {
+    sameFirst(
+      cyclesPer.struct(true, true, true, fastcat(true, true)),
+      sequence(0.25, 0.25, 0.25, fastcat(0.125, 0.125)).fmap(Fraction),
+    );
+  });
+});
+describe('per', () => {
+  it('gives haps per cycle', () => {
+    sameFirst(per.struct(true, true, true, fastcat(true, true)), sequence(4, 4, 4, fastcat(8, 8)).fmap(Fraction));
+  });
+});
+
+describe('perx', () => {
+  it('gives exponential haps per cycle', () => {
+    sameFirst(
+      perx.struct(true, true, true, fastcat(true, fastcat(true, true))),
+      sequence(3, 3, 3, fastcat(4, fastcat(5, 5))),
+    );
+  });
+});