abcjs/src/write/creation/elements/tempo-element.js

Renderer for abc music notation

//    abc_tempo_element.js: Definition of the TempoElement class.

var AbsoluteElement = require('./absolute-element');
var RelativeElement = require('./relative-element');

var TempoElement = function TempoElement(tempo, tuneNumber, createNoteHead) {
	this.type = "TempoElement";
	this.tempo = tempo;
	this.tempo.type = "tempo"; /// TODO-PER: this should be set earlier, in the parser, probably.
	this.tuneNumber = tuneNumber;
	// TODO: can these two properties be merged?
	this.totalHeightInPitches = 6;
	this.tempoHeightAbove = this.totalHeightInPitches;
	this.pitch = undefined; // This will be set later
	if (this.tempo.duration && !this.tempo.suppressBpm) {
		this.note = this.createNote(createNoteHead, tempo, tuneNumber);
	}
};

TempoElement.prototype.setX = function (x) {
	this.x = x;
};

TempoElement.prototype.createNote = function (createNoteHead, tempo, tuneNumber) {
	var temposcale = 0.75;
	var duration = tempo.duration[0]; // TODO when multiple durations
	var absElem = new AbsoluteElement(tempo, duration, 1, 'tempo', tuneNumber);
	// There aren't an infinite number of note values, but we are passed a float, so just in case something is off upstream,
	// merge all of the in between points.
	var dot;
	var flag;
	var note;
	if (duration <= 1 / 32) { note = "noteheads.quarter"; flag = "flags.u32nd"; dot = 0; }
	else if (duration <= 1 / 16) { note = "noteheads.quarter"; flag = "flags.u16th"; dot = 0; }
	else if (duration <= 3 / 32) { note = "noteheads.quarter"; flag = "flags.u16nd"; dot = 1; }
	else if (duration <= 1 / 8) { note = "noteheads.quarter"; flag = "flags.u8th"; dot = 0; }
	else if (duration <= 3 / 16) { note = "noteheads.quarter"; flag = "flags.u8th"; dot = 1; }
	else if (duration <= 1 / 4) { note = "noteheads.quarter"; dot = 0; }
	else if (duration <= 3 / 8) { note = "noteheads.quarter"; dot = 1; }
	else if (duration <= 1 / 2) { note = "noteheads.half"; dot = 0; }
	else if (duration <= 3 / 4) { note = "noteheads.half"; dot = 1; }
	else if (duration <= 1) { note = "noteheads.whole"; dot = 0; }
	else if (duration <= 1.5) { note = "noteheads.whole"; dot = 1; }
	else if (duration <= 2) { note = "noteheads.dbl"; dot = 0; }
	else { note = "noteheads.dbl"; dot = 1; }

	var ret = createNoteHead(absElem, note, { verticalPos: 0 }, // This is just temporary: we'll offset the vertical positioning when we get the actual vertical spot.
		{ dir: "up", flag: flag, dot: dot, scale: temposcale });
	var tempoNote = ret.notehead;
	absElem.addHead(tempoNote);
	var stem;
	if (note !== "noteheads.whole" && note !== "noteheads.dbl") {
		var p1 = 1 / 3 * temposcale;
		var p2 = 5 * temposcale;
		var dx = tempoNote.dx + tempoNote.w;
		var width = -0.6;
		stem = new RelativeElement(null, dx, 0, p1, { "type": "stem", "pitch2": p2, linewidth: width });
		absElem.addRight(stem);
	}
	return absElem;
};

module.exports = TempoElement;