this.cur = [0, 0];

	this.line_width = 2.0;

	this.dot_radius = 3.5;

	this.close_x = 1.5 * this.dot_radius;

	this.close_y = 0.5 * this.dot_radius;

	this.calcColor = function(color, bg, fg) {

		color %= colors.length;

		var red = (colors[color][0] * fg) || bg;

		var green = (colors[color][1] * fg) || bg;

		var blue = (colors[color][2] * fg) || bg;

		red = Math.round(red * 255);

		green = Math.round(green * 255);

		blue = Math.round(blue * 255);

		var s = 'rgb(' + red + ', ' + green + ', ' + blue + ')';

		return s;

	}

	this.setColor = function(color, bg, fg) {

		var s = this.calcColor(color, bg, fg);

		this.ctx.strokeStyle = s;

		this.ctx.fillStyle = s;

	}

	this.render = function(data,canvasWidth) {

		var idx = 1;

		var rela = this.canvas;

		this.canvas.setAttribute('width',canvasWidth);

		this.canvas.setAttribute('height',t.clientHeight);

		var lineCount = 1;

		for (var i=0;i<data.length;i++) {

			var in_l = data[i][1];

			for (var j in in_l) {

				var m = in_l[j][0];

				if (m > lineCount)

					lineCount = m;

			}

		}

		var edge_pad = this.dot_radius + 2;

		var box_size = Math.min(18, Math.floor((canvasWidth - edge_pad*2)/(lineCount)));

		var base_x = canvasWidth - edge_pad;

		for (var i=0; i < data.length; ++i) {

			var row = document.getElementById("chg_"+idx);

				continue;

			var	next = document.getElementById("chg_"+(idx+1));

			var extra = 0;

			cur = data[i];

			node = cur[0];

			in_l = cur[1];

			closing = cur[2];

			var rowY = row.offsetTop + row.offsetHeight/2 - rela.offsetTop;

			var nextY = (next == null) ? rowY + row.offsetHeight/2 : next.offsetTop + next.offsetHeight/2 - rela.offsetTop;

			for (var j in in_l) {

				line = in_l[j];

				start = line[0];

				end = line[1];

				color = line[2];

				x = base_x - box_size * start;

				// figure out if this is a dead-end;

				// we want to fade away this line

				var dead_end = true;

				if (next != null) {

					nextdata = data[i+1];

					next_l = nextdata[1];

					for (var k=0; k < next_l.length; ++k) {

						if (next_l[k][0] == end) {

							dead_end = false;

							break;

						}

					}

					if (nextdata[0][0] == end) // this is a root - not a dead end

						dead_end = false;

				}

				if (dead_end) {

					var gradient = this.ctx.createLinearGradient(x,rowY,x,nextY);

					gradient.addColorStop(0,this.calcColor(color, 0.0, 0.65));

					gradient.addColorStop(1,this.calcColor(color, 1.0, 0.0));

					this.ctx.strokeStyle = gradient;

					this.ctx.fillStyle = gradient;

				}

				// if this is a merge of differently

				// colored line, make it a gradient towards

				// the merged color

				else if (color != node[1] && start == node[0])

				{

					var gradient = this.ctx.createLinearGradient(x,rowY,x,nextY);

					gradient.addColorStop(0,this.calcColor(node[1], 0.0, 0.65));

					gradient.addColorStop(1,this.calcColor(color, 0.0, 0.65));

					this.ctx.strokeStyle = gradient;

					this.ctx.fillStyle = gradient;

				}

				else

				{

					this.setColor(color, 0.0, 0.65);

				}

				this.ctx.lineWidth=this.line_width;

				this.ctx.beginPath();

				this.ctx.moveTo(x, rowY);

				if (start == end)

				{

					this.ctx.lineTo(x,nextY+extra,3);

				}

				else

				{

					var x2 = base_x - box_size * end;

					var ymid = (rowY+nextY) / 2;

					this.ctx.bezierCurveTo (x,ymid,x2,ymid,x2,nextY);

				}

				this.ctx.stroke();