rickshaw/src/js/Rickshaw.Series.FixedDuration.js

Rickshaw is a JavaScript toolkit for creating interactive time series graphs, developed at [Shutterstock](http://www.shutterstock.com)

Rickshaw.namespace('Rickshaw.Series.FixedDuration');

Rickshaw.Series.FixedDuration = Rickshaw.Class.create(Rickshaw.Series, {

	initialize: function (data, palette, options) {

		var options = options || {}

		if (typeof(options.timeInterval) === 'undefined') {
			throw new Error('FixedDuration series requires timeInterval');
		}

		if (typeof(options.maxDataPoints) === 'undefined') {
			throw new Error('FixedDuration series requires maxDataPoints');
		}

		this.palette = new Rickshaw.Color.Palette(palette);
		this.timeBase = typeof(options.timeBase) === 'undefined' ? Math.floor(new Date().getTime() / 1000) : options.timeBase;
		this.setTimeInterval(options.timeInterval);

		if (this[0] && this[0].data && this[0].data.length) {
			this.currentSize = this[0].data.length;
			this.currentIndex = this[0].data.length;
		} else {
			this.currentSize  = 0;
			this.currentIndex = 0;
		}

		this.maxDataPoints = options.maxDataPoints;


		if (data && (typeof(data) == "object") && (data instanceof Array)) {
			data.forEach( function (item) { this.addItem(item) }, this );
			this.currentSize  += 1;
			this.currentIndex += 1;
		}

		// reset timeBase for zero-filled values if needed
		this.timeBase -= (this.maxDataPoints - this.currentSize) * this.timeInterval;

		// zero-fill up to maxDataPoints size if we don't have that much data yet
		if ((typeof(this.maxDataPoints) !== 'undefined') && (this.currentSize < this.maxDataPoints)) {
			for (var i = this.maxDataPoints - this.currentSize - 1; i > 0; i--) {
				this.currentSize  += 1;
				this.currentIndex += 1;
				this.forEach( function (item) {
					item.data.unshift({ x: ((i-1) * this.timeInterval || 1) + this.timeBase, y: 0, i: i });
				}, this );
			}
		}
	},

	addData: function($super, data) {

		$super(data)

		this.currentSize += 1;
		this.currentIndex += 1;

		if (this.maxDataPoints !== undefined) {
			while (this.currentSize > this.maxDataPoints) {
				this.dropData();
			}
		}
	},

	dropData: function() {

		this.forEach(function(item) {
			item.data.splice(0, 1);
		} );

		this.currentSize -= 1;
	},

	getIndex: function () {
		return this.currentIndex;
	}
} );