ExtJS 折线图：如何标记满足条件的点并标红

"Ext.onReady(function() {\n\t// 假设有一个数据集\n\tvar data = [\n\t\t{ x: 1, y: 5 },\n\t\t{ x: 2, y: 3 },\n\t\t{ x: 3, y: 8 },\n\t\t{ x: 4, y: 2 },\n\t\t{ x: 5, y: 7 },\n\t\t// ...\n\t];\n\n\t// 创建一个 store\n\tvar store = Ext.create('Ext.data.Store', {\n\t\tfields: ['x', 'y'],\n\t\tdata: data\n\t});\n\n\t// 创建一个折线图\n\tvar chart = Ext.create('Ext.chart.Chart', {\n\t\trenderTo: Ext.getBody(),\n\t\twidth: 400,\n\t\theight: 300,\n\t\tstore: store,\n\t\taxes: [\n\t\t\t{\n\t\t\t\ttype: 'numeric',\n\t\t\t\tposition: 'left',\n\t\t\t\tfields: ['y']\n\t\t\t},\n\t\t\t{\n\t\t\t\ttype: 'numeric',\n\t\t\t\tposition: 'bottom',\n\t\t\t\tfields: ['x']\n\t\t\t}\n\t\t],\n\t\tseries: [\n\t\t\t{\n\t\t\t\ttype: 'line',\n\t\t\t\txField: 'x',\n\t\t\t\tyField: 'y',\n\t\t\t\tmarker: {\n\t\t\t\t\ttype: 'circle',\n\t\t\t\t\tradius: 4, // 设置标记点的半径\n\t\t\t\t\tfill: 'red' // 设置标记点的颜色\n\t\t\t\t},\n\t\t\t\trenderer: function(sprite, record, attr, index, store) {\n\t\t\t\t\t// 根据条件判断是否需要标记某个点\n\t\t\t\t\tif (record.get('y') > 5) {\n\t\t\t\t\t\tattr.fill = 'red'; // 设置满足条件的点的颜色\n\t\t\t\t\t}\n\t\t\t\t\treturn attr;\n\t\t\t\t}\n\t\t\t}\n\t\t]\n\t});\n\n});\n"