/*

Sursa scriptului: http://www.phpied.com/canvas-pie/

*/


	function drawPie(numeTabelDate, numeCanvas) {
	    ///// STEP 0 - setup

	    // source data table and canvas tag
	    var data_table = document.getElementById(numeTabelDate);
	    var canvas = document.getElementById(numeCanvas);
	    var td_index = 1; // which TD contains the data

	    ///// STEP 1 - Get the, get the, get the data!

	    // get the data[] from the table
	    var tds, data = [], color, colors = [], value = 0, total = 0;
	    var trs = data_table.getElementsByTagName('tr'); // all TRs
	    for (var i = 0; i < trs.length; i++) {
		tds = trs[i].getElementsByTagName('td'); // all TDs

		if (tds.length === 0) continue; //  no TDs here, move on

		// get the value, update total
		value  = parseFloat(tds[td_index].innerHTML);
		data[data.length] = value;
		total += value;

		// random color
		color = getColor();
		colors[colors.length] = color; // save for later
		trs[i].style.backgroundColor = color; // color this TR
	    }


	    ///// STEP 2 - Draw pie on canvas


	    // exit if canvas is not supported
	    if (typeof canvas.getContext === 'undefined') {
		return;
	    }

	    // get canvas context, determine radius and center
	    var ctx = canvas.getContext('2d');
	    var canvas_size = [canvas.width, canvas.height];
	    var radius = Math.min(canvas_size[0], canvas_size[1]) / 2;
	    var center = [canvas_size[0]/2, canvas_size[1]/2];

	    var sofar = 0; // keep track of progress
	    // loop the data[]
	    for (var piece in data) {

		var thisvalue = data[piece] / total;

		ctx.beginPath();
		ctx.moveTo(center[0], center[1]); // center of the pie
		ctx.arc(  // draw next arc
		    center[0],
		    center[1],
		    radius,
		    Math.PI * (- 0.5 + 2 * sofar), // -0.5 sets set the start to be top
		    Math.PI * (- 0.5 + 2 * (sofar + thisvalue)),
		    false
		);

		ctx.lineTo(center[0], center[1]); // line back to the center
		ctx.closePath();
		ctx.fillStyle = colors[piece];    // color
		ctx.fill();

		sofar += thisvalue; // increment progress tracker
	    }
	}

    ///// DONE!


    // utility - generates random color
    function getColor() {
        var rgb = [];
        for (var i = 0; i < 3; i++) {
            rgb[i] = Math.round(100 * Math.random() + 155) ; // [155-255] = lighter colors
        }
        return 'rgb(' + rgb.join(',') + ')';
    }