javascript - 在 angular-chart.js 中使用渐变颜色

Question

我正在尝试使用 angular-chart.js 版本 1.0.0 为我的图表使用渐变，但似乎 fillcolor 无法识别渐变，这是我下面的代码

var app = angular.module('starter', ['ionic', 'ngCordova',   'chart.js',  'ionic-modal-select']).controller('graphCtrl', function($scope) {
  

 var ctx =  document.getElementById('base2').getContext('2d');
  
 var gradient =ctx.createLinearGradient(0, 0, 0, 400);
    gradient.addColorStop(0, 'rgba(243, 103, 101,0.5)');
    gradient.addColorStop(1, 'rgba(0, 89, 179,0.5)');
  
$scope.labels2 = ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday'];
 
 $scope.data2 = [
      [65, -59, 80, 81, -56, 55, -40],
      [28, 48, -40, 19, 86, 27, 90]
  ];
 $scope.type2 = 'bar';
  
  $scope.colors2 = [{
     fillColor: gradient,gradient angular js not responding
     strokeColor: 'rgba(151,187,205,1)',
     pointColor: 'rgba(151,187,205,1)',
     pointStrokeColor: '#fff',
     pointHighlightFill: '#fff',
     pointHighlightStroke: 'rgba(151,187,205,0.8)'
   }, {
     pointDot: false,
     pointDotRadius: 0,
     fillColor: gradient,
     strokeColor: 'rgba(187,155,206,1)',
     pointColor: '#BB9BCE',
    pointStrokeColor: 'rgba(187,155,206,1)',
    pointHighlightFill: '#fff',
    pointHighlightStroke: 'rgba(187,155,206,1)'
   }];
  
 $scope.datasetOverride2 = [{
      label: "Bar chart",
      borderWidbelowbelowth: 1,
      type: 'bar'
      
  }, {
      label: "Line chart",
      borderWidth: 3,

      hoverBackgroundColor: "rgba(255,99,132,0.4)",
      hoverBorderColor: "rgba(255,99,132,1)",
      type: 'line'
  }];
  
  
  });

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>
<div class="chart-container" >
    <canvas id="base2" class="chart-base" chart-type="type2" chart-          data="data2" chart-labels="labels2" chart-colours="colors2" chart-      options="options2" chart-dataset-override="datasetOverride2" >
   </canvas>
 </div>

如何声明渐变使其起作用？我试过了

var ctx = angular.element(document).find("canvas")[0].getContext("2d");
var gradient = ctx.createLinearGradient(0, 0, 0, 400);
gradient.addColorStop(0, 'rgba(243, 103, 101,0.5)');
gradient.addColorStop(1, 'rgba(0, 89, 179,0.5)');

但它也不起作用。

Answer 1

希望这个回答对和我有相同渐变问题的小伙伴有所帮助!

所以对我有用的是在图表上创建一个事件监听器，并在事件图表发出时调用我的函数 changeColor。

这是我 Controller 中的代码:

var changeColor = function(chart){
var ctx = chart.chart.ctx;
var gradient = ctx.createLinearGradient(0, 0, 0, 400);
gradient.addColorStop(0, 'rgba(243, 103, 101,0.5)');
gradient.addColorStop(1, 'rgba(0, 89, 179,0.5)');
chart.chart.config.data.datasets[0].backgroundColor = gradient;};


$scope.$on('chart-create', function (evt, chart) {
if(chart.chart.canvas.id === 'base2') {
  changeColor(chart);
  chart.update();
}

HTML代码

<canvas id="base2" class="chart-base" chart-type="type2" chart-data="data2" chart-labels="labels2" chart-colors="colors2" chart-options="options2" >
</canvas>