/**
 * Sample plugin.
 */
Draw.loadPlugin(function(ui) {

	/**
	 * Overrides SVG export to add metadata for each cell.
	 */
	var graphCreateSvgImageExport = Graph.prototype.createSvgImageExport;
	
	Graph.prototype.createSvgImageExport = function()
	{
		var exp = graphCreateSvgImageExport.apply(this, arguments);
		
		// Overrides rendering to add metadata
		var expDrawCellState = exp.drawCellState;

		exp.drawCellState = function(state, canvas)
		{
			var svgDoc = canvas.root.ownerDocument;
			var g = (svgDoc.createElementNS != null) ?
					svgDoc.createElementNS(mxConstants.NS_SVG, 'g') : svgDoc.createElement('g');
			g.setAttribute('id', 'cell-' + state.cell.id);

			// Temporary replaces root for content rendering
			var prev = canvas.root;
			prev.appendChild(g);
			canvas.root = g;
			
			expDrawCellState.apply(this, arguments);
			
			// Adds metadata if group is not empty
			if (g.firstChild == null)
			{
				g.parentNode.removeChild(g);
			}
			else if (mxUtils.isNode(state.cell.value))
			{
				g.setAttribute('content', mxUtils.getXml(state.cell.value));
				
				for (var i = 0; i < state.cell.value.attributes.length; i++)
				{
					var attrib = state.cell.value.attributes[i];
					g.setAttribute('data-' + attrib.name, attrib.value);
				}
			}
			
			// Restores previous root
			canvas.root = prev;
		};

		return exp;
	};
	
});