    /**
     * @class Ext.chart.Legend
     *
     * Defines a legend for a chart's series.
     * The 'chart' member must be set prior to rendering.
     * The legend class displays a list of legend items each of them related with a
     * series being rendered. In order to render the legend item of the proper series
     * the series configuration object must have `showInLegend` set to true.
     *
     * The legend configuration object accepts a `position` as parameter.
     * The `position` parameter can be `left`, `right`
     * `top` or `bottom`. For example:
     *
     *     legend: {
     *         position: 'right'
     *     },
     *
     * ## Example
     *
     *     @example
     *     var store = Ext.create('Ext.data.JsonStore', {
     *         fields: ['name', 'data1', 'data2', 'data3', 'data4', 'data5'],
     *         data: [
     *             { 'name': 'metric one',   'data1': 10, 'data2': 12, 'data3': 14, 'data4': 8,  'data5': 13 },
     *             { 'name': 'metric two',   'data1': 7,  'data2': 8,  'data3': 16, 'data4': 10, 'data5': 3  },
     *             { 'name': 'metric three', 'data1': 5,  'data2': 2,  'data3': 14, 'data4': 12, 'data5': 7  },
     *             { 'name': 'metric four',  'data1': 2,  'data2': 14, 'data3': 6,  'data4': 1,  'data5': 23 },
     *             { 'name': 'metric five',  'data1': 27, 'data2': 38, 'data3': 36, 'data4': 13, 'data5': 33 }
     *         ]
     *     });
     *
     *     Ext.create('Ext.chart.Chart', {
     *         renderTo: Ext.getBody(),
     *         width: 500,
     *         height: 300,
     *         animate: true,
     *         store: store,
     *         shadow: true,
     *         theme: 'Category1',
     *         legend: {
     *             position: 'top'
     *         },
     *         axes: [
     *             {
     *                 type: 'Numeric',
     *                 grid: true,
     *                 position: 'left',
     *                 fields: ['data1', 'data2', 'data3', 'data4', 'data5'],
     *                 title: 'Sample Values',
     *                 grid: {
     *                     odd: {
     *                         opacity: 1,
     *                         fill: '#ddd',
     *                         stroke: '#bbb',
     *                         'stroke-width': 1
     *                     }
     *                 },
     *                 minimum: 0,
     *                 adjustMinimumByMajorUnit: 0
     *             },
     *             {
     *                 type: 'Category',
     *                 position: 'bottom',
     *                 fields: ['name'],
     *                 title: 'Sample Metrics',
     *                 grid: true,
     *                 label: {
     *                     rotate: {
     *                         degrees: 315
     *                     }
     *                 }
     *             }
     *         ],
     *         series: [{
     *             type: 'area',
     *             highlight: false,
     *             axis: 'left',
     *             xField: 'name',
     *             yField: ['data1', 'data2', 'data3', 'data4', 'data5'],
     *             style: {
     *                 opacity: 0.93
     *             }
     *         }]
     *     });
     */
    Ext.define('Ext.chart.Legend', {

        /* Begin Definitions */

        requires: ['Ext.chart.LegendItem'],

        /* End Definitions */

        /**
         * @cfg {Boolean} visible
         * Whether or not the legend should be displayed.
         */
        visible: true,

        /**
         * @cfg {Boolean} update
         * If set to true the legend will be refreshed when the chart is.
         * This is useful to update the legend items if series are
         * added/removed/updated from the chart. Default is true.
         */
        update: true,

        /**
         * @cfg {String} position
         * The position of the legend in relation to the chart. One of: "top",
         * "bottom", "left", "right", or "float". If set to "float", then the legend
         * box will be positioned at the point denoted by the x and y parameters.
         */
        position: 'bottom',

        /**
         * @cfg {Number} x
         * X-position of the legend box. Used directly if position is set to "float", otherwise
         * it will be calculated dynamically.
         */
        x: 0,

        /**
         * @cfg {Number} y
         * Y-position of the legend box. Used directly if position is set to "float", otherwise
         * it will be calculated dynamically.
         */
        y: 0,

        /**
         * @cfg {String} labelColor
         * Color to be used for the legend labels, eg '#000'
         */
        labelColor: '#000',

        /**
         * @cfg {String} labelFont
         * Font to be used for the legend labels, eg '12px Helvetica'
         */
        labelFont: '12px Helvetica, sans-serif',

        /**
         * @cfg {String} boxStroke
         * Style of the stroke for the legend box
         */
        boxStroke: '#000',

        /**
         * @cfg {String} boxStrokeWidth
         * Width of the stroke for the legend box
         */
        boxStrokeWidth: 1,

        /**
         * @cfg {String} boxFill
         * Fill style for the legend box
         */
        boxFill: '#FFF',

        /**
         * @cfg {Number} itemSpacing
         * Amount of space between legend items
         */
        itemSpacing: 10,

        /**
         * @cfg {Number} padding
         * Amount of padding between the legend box's border and its items
         */
        padding: 5,

        // @private
        width: 0,
        // @private
        height: 0,

        /**
         * @cfg {Number} boxZIndex
         * Sets the z-index for the legend. Defaults to 100.
         */
        boxZIndex: 100,

        /**
         * Creates new Legend.
         * @param {Object} config  (optional) Config object.
         */
        constructor: function(config) {
            var me = this;
            if (config) {
                Ext.apply(me, config);
            }
            me.items = [];
            /**
             * Whether the legend box is oriented vertically, i.e. if it is on the left or right side or floating.
             * @type {Boolean}
             */
            me.isVertical = ("left|right|float".indexOf(me.position) !== -1);

            // cache these here since they may get modified later on
            me.origX = me.x;
            me.origY = me.y;
        },

        /**
         * @private Create all the sprites for the legend
         */
        create: function() {
            var me = this,
                seriesItems = me.chart.series.items,
                i, ln, series;

            me.createBox();

            if (me.rebuild !== false) {
                me.createItems();
            }

            if (!me.created && me.isDisplayed()) {
                me.created = true;

                // Listen for changes to series titles to trigger regeneration of the legend
                for (i = 0, ln = seriesItems.length; i < ln; i++) {
                    series = seriesItems[i];
                    series.on('titlechange', function() {
                        me.create();
                        me.updatePosition();
                    });
                }
            }
        },

        /**
         * @private Determine whether the legend should be displayed. Looks at the legend's 'visible' config,
         * and also the 'showInLegend' config for each of the series.
         */
        isDisplayed: function() {
            return this.visible && this.chart.series.findIndex('showInLegend', true) !== -1;
        },

        /**
         * @private Create the series markers and labels
         */
        createItems: function() {
            var me = this,
                chart = me.chart,
                seriesItems = chart.series.items,
                ln, series,
                surface = chart.surface,
                items = me.items,
                padding = me.padding,
                itemSpacing = me.itemSpacing,
                spacingOffset = 2,
                maxWidth = 0,
                maxHeight = 0,
                totalWidth = 0,
                totalHeight = 0,
                vertical = me.isVertical,
                math = Math,
                mfloor = math.floor,
                mmax = math.max,
                index = 0,
                i = 0,
                len = items ? items.length : 0,
                x, y, spacing, item, bbox, height, width,
                fields, field, nFields, j;

            //remove all legend items
            if (len) {
                for (; i < len; i++) {
                    items[i].destroy();
                }
            }
            //empty array
            items.length = [];
            // Create all the item labels, collecting their dimensions and positioning each one
            // properly in relation to the previous item
            for (i = 0, ln = seriesItems.length; i < ln; i++) {
                series = seriesItems[i];
                if (series.showInLegend) {
                    fields = [].concat(series.yField);
                    for (j = 0, nFields = fields.length; j < nFields; j++) {
                        field = fields[j];
                        item = new Ext.chart.LegendItem({
                            legend: this,
                            series: series,
                            surface: chart.surface,
                            yFieldIndex: j
                        });
                        bbox = item.getBBox();

                        //always measure from x=0, since not all markers go all the way to the left
                        width = bbox.width;
                        height = bbox.height;

                        if (i + j === 0) {
                            spacing = vertical ? padding + height / 2 : padding;
                        }
                        else {
                            spacing = itemSpacing / (vertical ? 2 : 1);
                        }
                        // Set the item's position relative to the legend box
                        item.x = mfloor(vertical ? padding : totalWidth + spacing);
                        item.y = mfloor(vertical ? totalHeight + spacing : padding + height / 2);

                        // Collect cumulative dimensions
                        totalWidth += width + spacing;
                        totalHeight += height + spacing;
                        maxWidth = mmax(maxWidth, width);
                        maxHeight = mmax(maxHeight, height);

                        items.push(item);
                    }
                }
            }

            // Store the collected dimensions for later
            me.width = mfloor((vertical ? maxWidth : totalWidth) + padding * 2);
            if (vertical && items.length === 1) {
                spacingOffset = 1;
            }
            me.height = mfloor((vertical ? totalHeight - spacingOffset * spacing : maxHeight) + (padding * 2));
            me.itemHeight = maxHeight;
        },

        /**
         * @private Get the bounds for the legend's outer box
         */
        getBBox: function() {
            var me = this;
            return {
                x: Math.round(me.x) - me.boxStrokeWidth / 2,
                y: Math.round(me.y) - me.boxStrokeWidth / 2,
                width: me.width,
                height: me.height
            };
        },

        /**
         * @private Create the box around the legend items
         */
        createBox: function() {
            var me = this,
                box, bbox;

            if (me.boxSprite) {
                me.boxSprite.destroy();
            }

            bbox = me.getBBox();
            //if some of the dimensions are NaN this means that we
            //cannot set a specific width/height for the legend
            //container. One possibility for this is that there are
            //actually no items to show in the legend, and the legend
            //should be hidden.
            if (isNaN(bbox.width) || isNaN(bbox.height)) {
                me.boxSprite = false;
                return;
            }

            box = me.boxSprite = me.chart.surface.add(Ext.apply({
                type: 'rect',
                stroke: me.boxStroke,
                "stroke-width": me.boxStrokeWidth,
                fill: me.boxFill,
                zIndex: me.boxZIndex
            }, bbox));

            box.redraw();
        },

        /**
         * @private Update the position of all the legend's sprites to match its current x/y values
         */
        updatePosition: function() {
            var me = this,
                items = me.items,
                i, ln,
                x, y,
                legendWidth = me.width || 0,
                legendHeight = me.height || 0,
                padding = me.padding,
                chart = me.chart,
                chartBBox = chart.chartBBox,
                insets = chart.insetPadding,
                chartWidth = chartBBox.width - (insets * 2),
                chartHeight = chartBBox.height - (insets * 2),
                chartX = chartBBox.x + insets,
                chartY = chartBBox.y + insets,
                surface = chart.surface,
                mfloor = Math.floor,
                bbox;

            if (me.isDisplayed()) {
                // Find the position based on the dimensions
                switch(me.position) {
                    case "left":
                        x = insets;
                        y = mfloor(chartY + chartHeight / 2 - legendHeight / 2);
                        break;
                    case "right":
                        x = mfloor(surface.width - legendWidth) - insets;
                        y = mfloor(chartY + chartHeight / 2 - legendHeight / 2);
                        break;
                    case "top":
                        x = mfloor(chartX + chartWidth / 2 - legendWidth / 2);
                        y = insets;
                        break;
                    case "bottom":
                        x = mfloor(chartX + chartWidth / 2 - legendWidth / 2);
                        y = mfloor(surface.height - legendHeight) - insets;
                        break;
                    default:
                        x = mfloor(me.origX) + insets;
                        y = mfloor(me.origY) + insets;
                }
                me.x = x;
                me.y = y;

                // Update the position of each item
                for (i = 0, ln = items.length; i < ln; i++) {
                    items[i].updatePosition();
                }

                bbox = me.getBBox();

                //if some of the dimensions are NaN this means that we
                //cannot set a specific width/height for the legend
                //container. One possibility for this is that there are
                //actually no items to show in the legend, and the legend
                //should be hidden.
                if (isNaN(bbox.width) || isNaN(bbox.height)) {
                    if (me.boxSprite) {
                        me.boxSprite.hide(true);
                    }
                } else {
                    if (!me.boxSprite) {
                        me.createBox();
                    }
                    // Update the position of the outer box
                    me.boxSprite.setAttributes(bbox, true);
                    me.boxSprite.show(true);
                }
            }
        },

        /** toggle
         * @param {Boolean} Whether to show or hide the legend.
         *
         */
        toggle: function(show) {
          var me = this,
              i = 0,
              items = me.items,
              len = items.length;

          if (me.boxSprite) {
              if (show) {
                  me.boxSprite.show(true);
              } else {
                  me.boxSprite.hide(true);
              }
          }

          for (; i < len; ++i) {
              if (show) {
                items[i].show(true);
              } else {
                  items[i].hide(true);
              }
          }

          me.visible = show;
        }
    });