Draw fingering charts foot-up, in grouped rows.

The foot and the double holes sit at the top of each narrow chart, and the mouthpiece sits at the bottom, matching hand-drawn tabs. Which holes are open or closed is unchanged. A repeat mark is shown only when the score repeats. Version 0.1.2.

Co-authored-by: catpersonisme <catpersonisme@gmail.com>

src/lib/score.ts

@@ -17,6 +17,10 @@ export type ScoreEvent = {
 export type Measure = {
   id: string;
   events: ScoreEvent[];
+  /** A forward repeat barline stands at the start of this measure. */
+  repeatForward?: boolean;
+  /** A backward repeat ends on this measure. The number is how many times to play the passage. */
+  repeatTimes?: number;
 };
 
 export type ScoreOrigin = "sample" | "upload" | "blank";
@@ -86,6 +90,33 @@ export function formatBeat(beat: number): string {
   return Number.isInteger(rounded) ? String(rounded) : String(rounded);
 }
 
+/** Extra full beats after the note itself. A half note in 4/4 returns 1. A dotted quarter returns 0. */
+export function extraBeatArrows(quarters: number, timeSignature: TimeSignature): number {
+  const perBeat = 4 / timeSignature.beatType;
+  if (!(perBeat > 0) || !(quarters > 0)) return 0;
+  const wholeBeats = Math.floor(quarters / perBeat + 1e-6);
+  return Math.max(0, wholeBeats - 1);
+}
+
+/** Group a lead into horizontal rows. A row holds about `budget` notes, and never splits a bar. */
+export function leadRows<T extends { events: { length: number } }>(measures: T[], budget = 14): T[][] {
+  const rows: T[][] = [];
+  let current: T[] = [];
+  let count = 0;
+  for (const measure of measures) {
+    const notes = Math.max(1, measure.events.length);
+    if (current.length > 0 && count + notes > budget) {
+      rows.push(current);
+      current = [];
+      count = 0;
+    }
+    current.push(measure);
+    count += notes;
+  }
+  if (current.length > 0) rows.push(current);
+  return rows;
+}
+
 export function blankScore(): Score {
   return {
     title: "Untitled line",