Legend.js

define(["dojo/_base/declare", "dijit/_WidgetBase", "dojox/gfx", "dojo/has", "dojo/has!dojo-bidi?./bidi/widget/Legend",
		"dojox/lang/functional", "dojo/dom", "dojo/dom-construct", "dojo/dom-class","dijit/registry"],
		function(declare, _WidgetBase, gfx, has, BidiLegend, df,
				dom, domConstruct, domClass, registry){

	var Legend = declare(_WidgetBase, {
		// summary:
		//		A legend for a chart. A legend contains summary labels for
		//		each series of data contained in the chart.
		//		
		//		Set the horizontal attribute to boolean false to layout legend labels vertically.
		//		Set the horizontal attribute to a number to layout legend labels in horizontal
		//		rows each containing that number of labels (except possibly the last row).
		//		
		//		(Line or Scatter charts (colored lines with shape symbols) )
		//		-o- Series1		-X- Series2		-v- Series3
		//		
		//		(Area/Bar/Pie charts (letters represent colors))
		//		[a] Series1		[b] Series2		[c] Series3

		chartRef:   "",
		horizontal: true,
		swatchSize: 18,

		legendBody: null,

		postCreate: function(){
			if(!this.chart && this.chartRef){
				this.chart = registry.byId(this.chartRef) || registry.byNode(dom.byId(this.chartRef));
				if(!this.chart){
					console.log("Could not find chart instance with id: " + this.chartRef);
				}
			}
			// we want original chart
			this.chart = this.chart.chart || this.chart;
		},
		buildRendering: function(){
			this.domNode = domConstruct.create("table",
					{role: "group", "aria-label": "chart legend", "class": "dojoxLegendNode"});
			this.legendBody = domConstruct.create("tbody", null, this.domNode);
			this.inherited(arguments);
		},
		startup: function(){
			this.refresh();
		},
		destroy: function(){
			if(this._surfaces){
				this._surfaces.forEach(function(surface){
					surface.destroy();
				});
			}
			this.inherited(arguments);
		},
		refresh: function(){
			// summary:
			//		regenerates the legend to reflect changes to the chart

			// cleanup
			if(this._surfaces){
				this._surfaces.forEach(function(surface){
					surface.destroy();
				});
			}
			this._surfaces = [];
			while(this.legendBody.lastChild){
				domConstruct.destroy(this.legendBody.lastChild);
			}

			if(this.horizontal){
				domClass.add(this.domNode, "dojoxLegendHorizontal");
				// make a container <tr>
				this._tr = domConstruct.create("tr", null, this.legendBody);
				this._inrow = 0;
			}

			// keep trying to reach this.series for compatibility reasons in case the user set them, but could be removed
			var s = this.series || this.chart.series;
			if(s.length == 0){
				return;
			}
			if(s[0].chart.plots[0].declaredClass == "dojox.charting.plot2d.Pie"){
				var t = s[0].chart.plots[0];
				if(typeof t.run.data[0] == "number"){
					var filteredRun = df.map(t.run.data, "Math.max(x, 0)");
					var slices = df.map(filteredRun, "/this", df.foldl(filteredRun, "+", 0));
					slices.forEach(function(x, i){
						this._addLabel(t.dyn[i], t._getLabel(x * 100) + "%");
					}, this);
				}else{
					t.run.data.forEach(function(x, i){
						this._addLabel(t.dyn[i], x.legend || x.text || x.y);
					}, this);
				}
			}else{
				s.forEach(function(x){
					this._addLabel(x.dyn, x.legend || x.name);
				}, this);
			}
		},
		_addLabel: function(dyn, label){
			// create necessary elements
			var wrapper = domConstruct.create("td"),
				icon = domConstruct.create("div", null, wrapper),
				text = domConstruct.create("label", null, wrapper),
				div  = domConstruct.create("div", {
					style: {
						"width": this.swatchSize + "px",
						"height":this.swatchSize + "px",
						"float": "left"
					}
				}, icon);
			domClass.add(icon, "dojoxLegendIcon dijitInline");
			domClass.add(text, "dojoxLegendText");
			// create a skeleton
			if(this._tr){
				// horizontal
				this._tr.appendChild(wrapper);
				if(++this._inrow === this.horizontal){
					// make a fresh container <tr>
					this._tr = domConstruct.create("tr", null, this.legendBody);
					this._inrow = 0;
				}
			}else{
				// vertical
				var tr = domConstruct.create("tr", null, this.legendBody);
				tr.appendChild(wrapper);
			}

			// populate the skeleton
			this._makeIcon(div, dyn);
			text.innerHTML = String(label);
			if(has("dojo-bidi")){
				text.dir = this.getTextDir(label, text.dir);
			}
		},
		_makeIcon: function(div, dyn){
			var mb = { h: this.swatchSize, w: this.swatchSize };
			var surface = gfx.createSurface(div, mb.w, mb.h);
			this._surfaces.push(surface);
			if(dyn.fill){
				// regions
				surface.createRect({x: 2, y: 2, width: mb.w - 4, height: mb.h - 4}).
					setFill(dyn.fill).setStroke(dyn.stroke);
			}else if(dyn.stroke || dyn.marker){
				// draw line
				var line = {x1: 0, y1: mb.h / 2, x2: mb.w, y2: mb.h / 2};
				if(dyn.stroke){
					surface.createLine(line).setStroke(dyn.stroke);
				}
				if(dyn.marker){
					// draw marker on top
					var c = {x: mb.w / 2, y: mb.h / 2};
					surface.createPath({path: "M" + c.x + " " + c.y + " " + dyn.marker}).
						setFill(dyn.markerFill).setStroke(dyn.markerStroke);
				}
			}else{
				// nothing
				surface.createRect({x: 2, y: 2, width: mb.w - 4, height: mb.h - 4}).
					setStroke("black");
				surface.createLine({x1: 2, y1: 2, x2: mb.w - 2, y2: mb.h - 2}).setStroke("black");
				surface.createLine({x1: 2, y1: mb.h - 2, x2: mb.w - 2, y2: 2}).setStroke("black");
			}
		}
	});
	return has("dojo-bidi")? declare([Legend, BidiLegend]) : Legend;
});