    /**
     * @class Ext.chart.Navigation
     *
     * Handles panning and zooming capabilities.
     *
     * Used as mixin by Ext.chart.Chart.
     */
    Ext.define('Ext.chart.Navigation', {

        constructor: function() {
            this.originalStore = this.store;
        },

        /**
         * Zooms the chart to the specified selection range.
         * Can be used with a selection mask. For example:
         *
         *     items: {
         *         xtype: 'chart',
         *         animate: true,
         *         store: store1,
         *         mask: 'horizontal',
         *         listeners: {
         *             select: {
         *                 fn: function(me, selection) {
         *                     me.setZoom(selection);
         *                     me.mask.hide();
         *                 }
         *             }
         *         }
         *     }
         */
        setZoom: function(zoomConfig) {
            var me = this,
                axes = me.axes,
                bbox = me.chartBBox,
                xScale = 1 / bbox.width,
                yScale = 1 / bbox.height,
                zoomer = {
                    x : zoomConfig.x * xScale,
                    y : zoomConfig.y * yScale,
                    width : zoomConfig.width * xScale,
                    height : zoomConfig.height * yScale
                };
            axes.each(function(axis) {
                var ends = axis.calcEnds();
                if (axis.position == 'bottom' || axis.position == 'top') {
                    var from = (ends.to - ends.from) * zoomer.x + ends.from,
                        to = (ends.to - ends.from) * zoomer.width + from;
                    axis.minimum = from;
                    axis.maximum = to;
                } else {
                    var to = (ends.to - ends.from) * (1 - zoomer.y) + ends.from,
                        from = to - (ends.to - ends.from) * zoomer.height;
                    axis.minimum = from;
                    axis.maximum = to;
                }
            });
            me.redraw(false);
        },

        /**
         * Restores the zoom to the original value. This can be used to reset
         * the previous zoom state set by `setZoom`. For example:
         *
         *     myChart.restoreZoom();
         */
        restoreZoom: function() {
            this.store = this.substore = this.originalStore;
            this.redraw(true);
        }

    });