谷歌图表：如何同步触发 2 个'ready'事件处理函数？

Question

我正在使用谷歌图表绘制折线图并使用 2 个现成的事件处理程序函数，如下所示：

对齐标题
1. ：将标题与中心对齐
2. CreateImageToExport：将图形转换为图像(使用 getImageURI(((

问题是这样形成的图像包含左对齐的标题(不反映 function1 的更改(。

相同的jsfiddle链接。

javascript代码：

    function drawBackgroundColor() {
      var data = new google.visualization.DataTable();
      data.addColumn('number', 'X');
      data.addColumn('number', 'Dogs');
      data.addRows([
        [0, 0],   [1, 10],  [2, 23],  [3, 17],  [4, 18],  [5, 9],
        [6, 11],  [7, 27],  [8, 33],  [9, 40],  [10, 32], [11, 35],
        [12, 30], [13, 40], [14, 42], [15, 47], [16, 44], [17, 48],
        [18, 52], [19, 54], [20, 42], [21, 55], [22, 56], [23, 57],
        [24, 60], [25, 50], [26, 52], [27, 51], [28, 49], [29, 53],
        [30, 55], [31, 60], [32, 61], [33, 59], [34, 62], [35, 65],
        [36, 62], [37, 58], [38, 55], [39, 61], [40, 64], [41, 65],
        [42, 63], [43, 66], [44, 67], [45, 69], [46, 69], [47, 70],
        [48, 72], [49, 68], [50, 66], [51, 65], [52, 67], [53, 70],
        [54, 71], [55, 72], [56, 73], [57, 75], [58, 70], [59, 68],
        [60, 64], [61, 60], [62, 65], [63, 67], [64, 68], [65, 69],
        [66, 70], [67, 72], [68, 75], [69, 80]
      ]);
      var options = {
        title: 'Popularity',
        hAxis: {
          title: 'Time'
        },
        vAxis: {
          title: 'Popularity'
        },
        backgroundColor: '#f1f8e9'
      };
      var vLeftMargin = '400';
      var chart = new google.visualization.LineChart(document.getElementById('chart_div'));
      google.visualization.events.addListener(chart, 'ready', AlignTitle);
      //Function to tilt the label
      function AlignTitle()
      {
          $('#chart_div').find("text:contains(" + options.title + ")").attr({'x': vLeftMargin});
      }
      //Add function to export
      CreateImageToExport   (chart,
                            'chart_div',
                            1000,
                            300); 
      chart.draw(data, options);
    }
//Function to create image to export 
function CreateImageToExport(pChart,
                             pDiv,
                             pWidth,
                             pHeight)
{
    google.visualization.events.addListener(pChart, 'ready', function () 
    {   
        $('#' + pDiv + '_Export').remove();
        var vExportedImage = document.createElement("img");
        vExportedImage.src = pChart.getImageURI();
        vExportedImage.width = pWidth;
        vExportedImage.height = pHeight;
        vExportedImage.id = pDiv + '_Export';
        document.getElementById('divImageCharts').appendChild(vExportedImage);
    });
}

我想在标题对齐后将图表转换为图像。任何建议都会有所帮助。谢谢

Answer 1

您可以在同一个'ready'事件中组合两者，以确保对齐在前。

google.visualization.events.addListener(chart, 'ready', function () {
  AlignTitle();
  CreateImageToExport(chart, 'chart_div', 1000, 300);
});

但是，这不会解决问题，
getImageURI不包括绘制图表后对图表所做的修改......

要获得带有自定义模组的图像，您可以使用 HTML2canvas

function CreateImageToExport(chartContainer, pWidth, pHeight) {
  html2canvas(chartContainer, {
    allowTaint: true,
    taintTest: false
  }).then(function(canvas) {
    var browserIsIE = false || !!document.documentMode;
    var domURL = window.URL || window.webkitURL || window;
    var imageURI;
    if (browserIsIE) {
      imageURI = domURL.createObjectURL(canvas.msToBlob(), {type: 'image/png'});
    } else {
      imageURI = canvas.toDataURL('image/png');
    }
    $('#' + chartContainer.id + '_Export').remove();
    var vExportedImage = document.createElement('img');
    vExportedImage.src = imageURI;
    vExportedImage.width = pWidth;
    vExportedImage.height = pHeight;
    vExportedImage.id = chartContainer.id + '_Export';
    document.getElementById('divImageCharts').appendChild(vExportedImage);
  });
}

请参阅此小提琴以获取工作示例...

https://jsfiddle.net/274qjomw/11/(由于某种原因，HTML2canvas在StackOverflow代码段中不起作用(