Flex4 - 给LineChart线图添加拖动放大功能
有时候线图或面积图里数据太密集,如果想要重点关注,或者看清其中某一段时间的数据趋势。就需要给图表添加一个动态缩放功能。
即允许鼠标在图上拖动选择一个区域,图表便自动放大展示这块区域的内容。同时放大后右上角还会出现一个“还原”按钮,点击恢复成最初状态。
效果图如下:
代码如下:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 | <?xml version= "1.0" ?> <s:Application xmlns:fx= "http://ns.adobe.com/mxml/2009" creationComplete= "init(event)" > <fx:Script> <![CDATA[ import mx.charts.chartClasses.Series; import mx.collections.ArrayCollection; import mx.events.FlexEvent; //原始数据 private var _myData:ArrayCollection = new ArrayCollection( [ {time: "10:00" , value1: 34 , value2: 54 }, {time: "10:05" , value1: 35 , value2: 65 }, {time: "10:10" , value1: 25 , value2: 34 }, {time: "10:15" , value1: 36 , value2: 56 }, {time: "10:20" , value1: 54 , value2: 45 }, {time: "10:25" , value1: 63 , value2: 66 }, {time: "10:30" , value1: 23 , value2: 34 }, {time: "10:35" , value1: 55 , value2: 73 }, {time: "10:40" , value1: 64 , value2: 44 }, {time: "10:45" , value1: 75 , value2: 23 }, {time: "10:50" , value1: 31 , value2: 56 }, {time: "10:55" , value1: 33 , value2: 43 }, {time: "11:00" , value1: 34 , value2: 55 }, {time: "11:05" , value1: 23 , value2: 23 }, {time: "11:10" , value1: 25 , value2: 34 }, {time: "11:15" , value1: 23 , value2: 56 }, {time: "11:20" , value1: 54 , value2: 45 }, {time: "11:25" , value1: 63 , value2: 43 }, {time: "11:30" , value1: 34 , value2: 32 }, {time: "11:35" , value1: 33 , value2: 43 }, {time: "11:40" , value1: 54 , value2: 15 }, {time: "11:45" , value1: 75 , value2: 23 }, {time: "11:50" , value1: 13 , value2: 43 }, {time: "11:55" , value1: 33 , value2: 32 }, {time: "12:00" , value1: 34 , value2: 54 }, {time: "12:05" , value1: 35 , value2: 65 }, {time: "12:10" , value1: 25 , value2: 34 }, {time: "12:15" , value1: 32 , value2: 56 }, {time: "12:20" , value1: 54 , value2: 45 }, {time: "12:25" , value1: 63 , value2: 66 }, {time: "12:30" , value1: 53 , value2: 34 }, {time: "12:35" , value1: 55 , value2: 43 }, {time: "12:40" , value1: 64 , value2: 33 }, {time: "12:45" , value1: 75 , value2: 23 }, {time: "12:50" , value1: 31 , value2: 56 }, {time: "12:55" , value1: 23 , value2: 43 }, {time: "13:00" , value1: 45 , value2: 52 }, {time: "13:05" , value1: 34 , value2: 34 }, {time: "13:10" , value1: 25 , value2: 34 }, {time: "13:15" , value1: 23 , value2: 56 }, {time: "13:20" , value1: 54 , value2: 43 }, {time: "13:25" , value1: 63 , value2: 43 }, {time: "13:30" , value1: 44 , value2: 55 }, {time: "13:35" , value1: 33 , value2: 43 }, {time: "13:40" , value1: 54 , value2: 23 }, {time: "13:45" , value1: 75 , value2: 23 }, {time: "13:50" , value1: 13 , value2: 55 }, {time: "13:55" , value1: 33 , value2: 32 } ]); //放大区域的开始时间 private var _zoomStartTime: String = "" ; //放大区域的结束时间 private var _zoomEndTime: String = "" ; //放大区域的开始索引 private var _zoomStartIndex: int =- 1 ; //放大区域的结束索引 private var _zoomEndIndex: int =- 1 ; //页面初始化 protected function init(event:FlexEvent): void { vAxis.maximum = 100 ; loadData(); } //数据加载 private function loadData(): void { linechart.dataProvider = _myData; zoomOutBtn.visible = false ; } //鼠标按下 protected function linechart_mouseDownHandler(event:MouseEvent): void { //记下鼠标按下时的时间和位置 _zoomStartTime = getTimeNearMouse(); for ( var index: int = 0 ;index<linechart.dataProvider.length;index++){ if (linechart.dataProvider.getItemAt(index).time == _zoomStartTime){ _zoomStartIndex = index; break ; } } } //鼠标移动 private function linechart_mouseMoveHandler(event:MouseEvent): void { if (_zoomStartTime != "" ){ //记下鼠标移动时的时间和位置 _zoomEndTime = getTimeNearMouse(); for ( var index: int = 0 ;index<linechart.dataProvider.length;index++){ if (linechart.dataProvider.getItemAt(index).time == _zoomEndTime){ _zoomEndIndex = index; break ; } } //绘制 选中区域背景 var startX: Number = linechart.series[ 0 ].items[_zoomStartIndex][ "x" ]; var endX: Number = linechart.series[ 0 ].items[_zoomEndIndex][ "x" ];; zoomArea.graphics.clear(); zoomArea.graphics.beginFill( 0x65EEFC , 0.4 ); zoomArea.graphics.drawRect(startX, 0 ,endX-startX,chartBg.height); zoomArea.graphics.endFill(); } } //鼠标弹起 protected function linechart_mouseUpHandler(event:MouseEvent): void { if (_zoomStartTime!= "" ){ zoomIn() } _zoomStartTime = "" ; } //开始缩放 private function zoomIn(): void { zoomArea.graphics.clear(); //避免单击也放大 if (_zoomStartTime == _zoomEndTime){ return ; } zoomOutBtn.visible = true ; //保证开始索引小于结束索引(不管鼠标从左向右拖 还是从右向左拖) if (_zoomStartIndex>_zoomEndIndex){ var t: int = _zoomStartIndex; _zoomStartIndex = _zoomEndIndex; _zoomEndIndex = t; } //只加载选中区域的数据 var zoomData:ArrayCollection = new ArrayCollection(); for ( var index: int = 0 ;index<linechart.dataProvider.length;index++){ if (index<=_zoomEndIndex && index >=_zoomStartIndex){ zoomData.addItem(linechart.dataProvider.getItemAt(index)); } } linechart.dataProvider = zoomData; } //获取最接近鼠标位置的时间 private function getTimeNearMouse(): String { if (linechart.series[ 0 ]!= null ){ var series:Series = linechart.series[ 0 ]; var leftPoint:Point = new Point(series.mouseX, 0 ); var leftArr: Array = series.localToData(leftPoint); return leftArr[ 0 ]; } else { return "" ; } } ]]> </fx:Script> <fx:Declarations> <!-- 轴线样式 (暂时不需要,改成背景上绘制)--> <mx:SolidColorStroke id = "axisS1" color= "0xE3E3E3" weight= "1" alpha= "0" /> </fx:Declarations> <s:Group id= "chartGroup" width= "60%" height= "60%" verticalCenter= "0" horizontalCenter= "0" > <mx:LineChart id= "linechart" top= "10" bottom= "0" width= "100%" seriesFilters= "[]" fontSize= "12" color= "0x707070" showDataTips= "true" mouseMove= "linechart_mouseMoveHandler(event)" mouseDown= "linechart_mouseDownHandler(event)" mouseUp= "linechart_mouseUpHandler(event)" rollOut= "linechart_mouseUpHandler(event)" > <mx:backgroundElements> <s:Group width= "100%" height= "100%" id= "chartBg" > <s:Rect left= "0" right= "1" top= "0" bottom= "0" > <s:fill> <s:SolidColor alpha= "1" color= "#F5F5F5" /> </s:fill> <s:stroke> <s:SolidColorStroke color= "0xE3E3E3" weight= "1" /> </s:stroke> </s:Rect> <s:Group width= "100%" height= "100%" id= "zoomArea" > <!-- 在此绘制选中区域 --> </s:Group> </s:Group> <mx:GridLines gridDirection= "both" > <mx:horizontalStroke> <mx:SolidColorStroke color= "0xE3E3E3" weight= "1" /> </mx:horizontalStroke> <mx:verticalStroke> <mx:SolidColorStroke color= "0xEAEAEA" weight= "1" /> </mx:verticalStroke> </mx:GridLines> <s:Group width= "100%" height= "100%" > <s:Button id= "zoomOutBtn" label = "还原" right= "0" click= "loadData()" visible= "false" /> </s:Group> </mx:backgroundElements> <mx:horizontalAxis> <mx:CategoryAxis id= "hAxis" categoryField= "time" /> </mx:horizontalAxis> <mx:horizontalAxisRenderers> <mx:AxisRenderer axis= "{hAxis}" tickPlacement= "none" minorTickPlacement= "none" axisStroke= "{axisS1}" canDropLabels= "true" /> </mx:horizontalAxisRenderers> <mx:verticalAxis> <mx:LinearAxis id= "vAxis" /> </mx:verticalAxis> <mx:verticalAxisRenderers> <mx:AxisRenderer axis= "{vAxis}" tickPlacement= "none" minorTickPlacement= "none" axisStroke= "{axisS1}" /> </mx:verticalAxisRenderers> <mx:series> <mx:LineSeries id= "line1" yField= "value1" form= "segment" displayName= "数量1" > <mx:lineStroke> <mx:SolidColorStroke color= "0x008EFF" weight= "2" /> </mx:lineStroke> </mx:LineSeries> <mx:LineSeries id= "line2" yField= "value2" form= "segment" displayName= "数量2" > <mx:lineStroke> <mx:SolidColorStroke color= "0x1ACE4D" weight= "2" /> </mx:lineStroke> </mx:LineSeries> </mx:series> </mx:LineChart> </s:Group> </s:Application> |