我的图表生成函数如下：

createChart(db_data: string[], count: number[]) {
    const chartOptions = {
      type: 'horizontalBar',
      data: {
        labels: db_data,
        datasets: [
          {
            label: 'Chart',
            data: count,
            borderColor: '#99f0d1',
            backgroundColor: '#60b3a1',
            borderWidth: 0.1,
          },
          
        ],
      },
      onAnimationComplete: function()
      {
          this.showTooltip(this.datasets[0].data, true);
      },
      options: {
...
    this.chartElement = document.getElementById('canvas');
    this.chart = new Chart(this.chartElement, chartOptions);

我想导出为图像（PNG），但诀窍是，我想修改背景和酒吧的颜色。我的导出功能运行良好，但我不能设置修改后的背景属性。

exportChart() {
  const currentDate = new Date().toISOString().slice(0, 10);
  
  
  const canvas = this.chart.canvas;
  console.log(canvas);
  canvas.style.backgroundColor = 'blue';
  const chartDataURL = this.chart.toBase64Image();
  
  canvas.style.backgroundColor = 'blue'; 
  const link = document.createElement('a');
  link.href = chartDataURL;
  link.download = `statistic_${currentDate}.png`;
  link.click();
}

我试图修改图表生成（与ctx）