cahrts学习

最近公司项目要用到chart.js，故开始学习。以前从未接触过，本人学前端3个月左右。也是刚听说过echart。还不知道chart和echart的差别。我想总有机会把这两插件都了解的。那些了解charts。

先来个中文的api地址：http://www.bootcss.com/p/chart.js/docs/。

不过我总觉得中文的不太齐全，也可以看看英文的，就当学英语了：http://chartjs.cn/docs/#getting-started-include-chart.js

先把API粗略的浏览了一遍，内容相当少。接下去可以自己动手试试了。

一、创建图标根据API先HTML部分，记得canvas外面一定要套一个div，用于规定图表大小。

<div style="height: 400px; width: 400px; overflow: hidden;">

<canvas id="chart" ></canvas>
</div>

二、导入js，如果用jQuery创建，别忘了导入jQuery

<script type="text/javascript" src="js/jquery-2.2.3.min.js</script>
<script type="text/javascript" src="js/Chart.js" ></script>

 三、创建图表，这里以双曲线为例

 var areaChart1Canvas = $("#chart").get(0).getContext("2d");
    // This will get the first returned node in the jQuery collection.
    var areaChart1 = new Chart(areaChart1Canvas);
    var areaChart1Data = {
      labels: ["生产一部", "生产二部", "市场一部", "市场二部", "服务部", "后勤部", "园区过道"],
      datasets: [
        {
          label: "Electronics",
          fillColor: "rgba(210, 214, 222, 1)",
          strokeColor: "rgba(210, 214, 222, 1)",
          pointColor: "rgba(210, 214, 222, 1)",
          pointStrokeColor: "#c1c7d1",
          pointHighlightFill: "red",
          pointHighlightStroke: "red",
          data: [65, 59, 80, 81, 56, 55, 40]
        },
        {
          label: "Digital Goods",
          fillColor: "rgba(60,141,188,0.9)",
          strokeColor: "rgba(60,141,188,0.8)",
          pointColor: "#3b8bba",
          pointStrokeColor: "rgba(60,141,188,1)",
          pointHighlightFill: "#fff",
          pointHighlightStroke: "rgba(60,141,188,1)",
          data: []//也可以通过外面push进去
        }
      ]
    };
    var arry=[28, 48, 40, 19, 86, 27, 90];
    for(var i=0;i<arry.length;i++){
        areaChart1Data.datasets[1].data.push(arry[i]);//将数组写进data
    }

    var areaChart1Options = {
      //Boolean - If we should show the scale at all
      showScale: true,
      //Boolean - Whether grid lines are shown across the chart
      scaleShowGridLines: false,
      //String - Colour of the grid lines
      scaleGridLineColor: "rgba(0,0,0,.05)",
      //Number - Width of the grid lines
      scaleGridLineWidth: 1,
      //Boolean - Whether to show horizontal lines (except X axis)
      scaleShowHorizontalLines: true,
      //Boolean - Whether to show vertical lines (except Y axis)
      scaleShowVerticalLines: true,
      //Boolean - Whether the line is curved between points
      bezierCurve: true,
      //Number - Tension of the bezier curve between points
      bezierCurveTension: 0.3,
      //Boolean - Whether to show a dot for each point
      pointDot: false,
      //Number - Radius of each point dot in pixels
      pointDotRadius: 4,
      //Number - Pixel width of point dot stroke
      pointDotStrokeWidth: 1,
      //Number - amount extra to add to the radius to cater for hit detection outside the drawn point
      pointHitDetectionRadius: 20,
      //Boolean - Whether to show a stroke for datasets
      datasetStroke: true,
      //Number - Pixel width of dataset stroke
      datasetStrokeWidth: 2,
      //Boolean - Whether to fill the dataset with a color
      datasetFill: true,
      //String - A legend template
      legendTemplate: "<ul class=\"<%=name.toLowerCase()%>-legend\"><% for (var i=0; i<datasets.length; i++){%><li><span style=\"background-color:<%=datasets[i].lineColor%>\"></span><%if(datasets[i].label){%><%=datasets[i].label%><%}%></li><%}%></ul>",
      //Boolean - whether to maintain the starting aspect ratio or not when responsive, if set to false, will take up entire container
      maintainAspectRatio: true,
      //Boolean - whether to make the chart responsive to window resizing
      responsive: true
    };

    //Create the line chart
    areaChart1.Line(areaChart1Data, areaChart1Options);

到这里一定要注意各种插件以及canvas的位置。canvas要在charts插件前面，后门具体创建图表的代码要在插件后面。总之，按我这里的顺序来是准没错的。

四、到目前为止，一个双曲线图就创建好了。但是如果我们要建另一个图，却用到上面曲线图的数据怎么办，这里可以直接调用，并且修改个别参数。代码如下。

    var barChart1Canvas = $("#barChart1").get(0).getContext("2d");
    var barChart1 = new Chart(barChart1Canvas);
    var barChart1Data = areaChart1Data;
    barChart1Data.datasets[1].fillColor = "#0073b7";
    barChart1Data.datasets[1].strokeColor = "#0073b7";
    barChart1Data.datasets[1].pointColor = "#0073b7";
    var barChart1Options = {
      //Boolean - Whether the scale should start at zero, or an order of magnitude down from the lowest value
      scaleBeginAtZero: true,
      //Boolean - Whether grid lines are shown across the chart
      scaleShowGridLines: true,
      //String - Colour of the grid lines
      scaleGridLineColor: "rgba(0,0,0,.05)",
      //Number - Width of the grid lines
      scaleGridLineWidth: 0,
      //Boolean - Whether to show horizontal lines (except X axis)
      scaleShowHorizontalLines: true,
      //Boolean - Whether to show vertical lines (except Y axis)
      scaleShowVerticalLines: true,
      //Boolean - If there is a stroke on each bar
      barShowStroke: true,
      //Number - Pixel width of the bar stroke
      barStrokeWidth: 2,
      //Number - Spacing between each of the X value sets
      barValueSpacing:4,
      //Number - Spacing between data sets within X values
      barDatasetSpacing:0,
      //String - A legend template
      legendTemplate: "<ul class=\"<%=name.toLowerCase()%>-legend\"><% for (var i=0; i<datasets.length; i++){%><li><span style=\"background-color:<%=datasets[i].fillColor%>\"></span><%if(datasets[i].label){%><%=datasets[i].label%><%}%></li><%}%></ul>",
      //Boolean - whether to make the chart responsive
      responsive: true,
      maintainAspectRatio: true
    };

    barChart1Options.datasetFill = false;
    barChart1.Bar(barChart1Data, barChart1Options);

至于具体参数的含义，这里有英文的注释，就不翻译了。实在不理解可以把这里的代码复制过去，然后一一尝试。