tune-api-only.js

// See all scales at: http://abbernie.github.io/tune/scales.html


function Tune(){

	// the scale as ratios
	this.scale = []

	// i/o modes
	this.mode = {
		output: "frequency",
		input: "step"
	}

	// ET major, for reference
	this.etmajor = [ 261.62558,
		293.664764,
		329.627563,
		349.228241,
		391.995422,
		440,
		493.883301,
		523.25116
	]

	// Root frequency.
	this.tonic = 440     // * Math.pow(2,(60-69)/12);

	console.log("{{{{ Tune.js v0.1 Loaded }}}}");

}

/* Set the tonic frequency */

Tune.prototype.tonicize = function(newTonic) {
	this.tonic = newTonic
}


/* Return data in the mode you are in (freq, ratio, or midi) */

Tune.prototype.note = function(input,octave){

	var newvalue;

	if (this.mode.output == "frequency") { 
		newvalue = this.frequency(input,octave)
	} else if (this.mode.output == "ratio") { 
		newvalue = this.ratio(input,octave)
	} else if (this.mode.output == "MIDI") { 
		newvalue = this.MIDI(input,octave)
	} else {
		newvalue = this.frequency(input,octave)
	}
	
	return newvalue;

}


/* Return freq data */

Tune.prototype.frequency = function(stepIn, octaveIn) {

	if (this.mode.input == "midi" || this.mode.input == "MIDI" ) {
		this.stepIn += 60
	}
	
	// what octave is our input
	var octave = Math.floor(stepIn/this.scale.length)

	if (octaveIn) { 
		octave += octaveIn
	}
	
	// which scale degree (0 - scale length) is our input
	var scaleDegree = stepIn % this.scale.length

	while (scaleDegree < 0) {
		scaleDegree += this.scale.length
	}
	
	var freq = this.tonic*this.scale[scaleDegree]
	
	freq = freq*(Math.pow(2,octave))
	
	// truncate irrational numbers
	freq = Math.floor(freq*100000000000)/100000000000
	
	return freq

}

/* Force return ratio data */

Tune.prototype.ratio = function(stepIn, octaveIn) {

	if (this.mode.input == "midi" || this.mode.input == "MIDI" ) {
		this.stepIn += 60
	}
	
	// what octave is our input
	var octave = Math.floor(stepIn/this.scale.length)

	if (octaveIn) { 
		octave += octaveIn
	}
	
	// which scale degree (0 - scale length) is our input
	var scaleDegree = stepIn % this.scale.length

	// what ratio is our input to our key
	var ratio = Math.pow(2,octave)*this.scale[scaleDegree]

	ratio = Math.floor(ratio*100000000000)/100000000000

	return ratio

}

/* Force return adjusted MIDI data */

Tune.prototype.MIDI = function(stepIn,octaveIn) {

	var newvalue = this.frequency(stepIn,octaveIn)

	var n = 69 + 12*Math.log(newvalue/440)/Math.log(2)

	n = Math.floor(n*1000000000)/1000000000

	return n

}

/* Load a new scale */

Tune.prototype.loadScale = function(name){

	/* load the scale */
	var freqs = TuningList[name].frequencies
	this.scale = []
	for (var i=0;i<freqs.length-1;i++) {
		this.scale.push(freqs[i]/freqs[0])
	}

	/* visualize in console */
	console.log(" ");
	console.log("LOADED "+name);
	console.log(TuningList[name].description);
	console.log(this.scale);
	var vis = [];
	for (var i=0;i<100;i++) {
		vis[i] = " ";
	}
	for (var i=0;i<this.scale.length;i++) {
		var spot = Math.round(this.scale[i] * 100 - 100);
		if (i<10) {
			vis.splice(spot,1,i+1);
		} else {
			vis.splice(spot,5,i+1);
		}
	}
	var textvis = "";
	for (var i=0;i<vis.length;i++) {
		textvis += vis[i];
	}
	console.log(name)
	console.log(textvis)
	// ET scale vis
	var vis = [];
	for (var i=0;i<100;i++) {
		vis[i] = " ";
	}
	for (var i=0;i<this.etmajor.length;i++) {
		var spot = Math.round(this.etmajor[i]/this.etmajor[0] * 100 - 100);
		if (i<10) {
			vis.splice(spot,1,i+1);
		} else {
			vis.splice(spot,5,i+1);
		}
		
	}
	var textvis = "";
	for (var i=0;i<vis.length;i++) {
		textvis += vis[i];
	}
	console.log(textvis)
	console.log("equal-tempered major (reference)")

}

/* Search the names of tunings
	 Returns an array of names of tunings */

Tune.prototype.search = function(letters) {
	var possible = []
	for (var key in TuningList) {
		if (key.toLowerCase().indexOf(letters.toLowerCase())!=-1) {
			possible.push(key)
		}
	}
	return possible
}

/* Return a collection of notes as an array */

Tune.prototype.chord = function(midis) {
	var output = []
	for (var i=0;i<midis.length;i++) {
		output.push(this.note(midis[i]))
	}
	return output;
}


/* Change the tonic frequency? */

Tune.prototype.root = function(newmidi, newfreq) {
	this.rootFreq = newfreq
	// not working now ... needs much work.
	// setKey is not transposing now, either.
}