Merge pull request #89 from ThebestkillerTBK/master

Dynamic tempo support
grimmdude · Feb 8, 2022 · 0a06954 · 0a06954
2 parents bc8751e + 9a69d5c
commit 0a06954
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Showing 3 changed files with 9 additions and 3 deletions.
diff --git a/src/meta-events/tempo-event.js b/src/meta-events/tempo-event.js
@@ -15,6 +15,8 @@ class TempoEvent {
 
 		this.type = 'tempo';
 
+		this.tick = fields.tick;
+
 		const tempo = Math.round(60000000 / fields.bpm);
 
 		// Start with zero time delta

diff --git a/src/track.js b/src/track.js
@@ -110,6 +110,9 @@ class Track {
 				precisionLoss = Utils.getPrecisionLoss(event.deltaWithPrecisionCorrection || 0);
 				this.data = this.data.concat(built.data);
 				this.tickPointer = Utils.getRoundedIfClose(event.tick);
+			} else if (event instanceof TempoEvent) {
+				this.tickPointer = Utils.getRoundedIfClose(event.tick);
+				this.data = this.data.concat(event.data);
 			} else {
 				this.data = this.data.concat(event.data);
 			}
@@ -206,10 +209,11 @@ class Track {
 	/**
 	 * Sets tempo of the MIDI file.
 	 * @param {number} bpm - Tempo in beats per minute.
+	 * @param {number} tick - Start tick.
 	 * @return {Track}
 	 */
-	setTempo(bpm) {
-		return this.addEvent(new TempoEvent({bpm}));
+	setTempo(bpm, tick = 0) {
+	   return this.addEvent(new TempoEvent({bpm, tick}));
 	}
 
 	/**

diff --git a/types.d.ts b/types.d.ts
@@ -89,7 +89,7 @@ declare module "midi-writer-js" {
 			event: EventType | EventType[],
 			mapFunction?: (index: number, event: EventType) => Partial<EventType>
 		): void;
-		setTempo(tempo: number): void;
+		setTempo(tempo: number, tick: number): void;
 		addText(text: string): void;
 		addCopyright(text: string): void;
 		addTrackName(text: string): void;