1/*
2drawLine.mjs - <short description TODO>
3Copyright (C) 2022 Strudel contributors - see <https://codeberg.org/uzu/strudel/src/branch/main/packages/core/drawLine.mjs>
4This 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/>.
5*/
6
7import Fraction, { gcd } from './fraction.mjs';
8
9/**
10 * Intended for a debugging, drawLine renders the pattern as a string, where each character represents the same time span.
11 * Should only be used with single characters as values, otherwise the character slots will be messed up.
12 * Character legend:
13 *
14 * - "|" cycle separator
15 * - "-" hold previous value
16 * - "." silence
17 *
18 * @tags visualization
19 * @param {Pattern} pattern the pattern to use
20 * @param {number} chars max number of characters (approximately)
21 * @returns string
22 * @example
23 * const line = drawLine("0 [1 2 3]", 10); // |0--123|0--123
24 * console.log(line);
25 * silence;
26 */
27function drawLine(pat, chars = 60) {
28  let cycle = 0;
29  let pos = Fraction(0);
30  let lines = [''];
31  let emptyLine = ''; // this will be the "reference" empty line, which will be copied into extra lines
32  while (lines[0].length < chars) {
33    const haps = pat.queryArc(cycle, cycle + 1);
34    const durations = haps.filter((hap) => hap.hasOnset()).map((hap) => hap.duration);
35    const charFraction = gcd(...durations);
36    const totalSlots = charFraction.inverse(); // number of character slots for the current cycle
37    lines = lines.map((line) => line + '|'); // add pipe character before each cycle
38    emptyLine += '|';
39    for (let i = 0; i < totalSlots; i++) {
40      const [begin, end] = [pos, pos.add(charFraction)];
41      const matches = haps.filter((hap) => hap.whole.begin.lte(begin) && hap.whole.end.gte(end));
42      const missingLines = matches.length - lines.length;
43      if (missingLines > 0) {
44        lines = lines.concat(Array(missingLines).fill(emptyLine));
45      }
46      lines = lines.map((line, i) => {
47        const hap = matches[i];
48        if (hap) {
49          const isOnset = hap.whole.begin.eq(begin);
50          const char = isOnset ? '' + hap.value : '-';
51          return line + char;
52        }
53        return line + '.';
54      });
55      emptyLine += '.';
56      pos = pos.add(charFraction);
57    }
58    cycle++;
59  }
60  return lines.join('\n');
61}
62
63export default drawLine;