message: fix(image): svg image src may be a canvas element. (see echarts/test/heatmap-map.html)
diff: @@ -324,8 +324,11 @@ const svgImage: SVGProxy<ZRImage> = {
  let image = style.image;
  if (image instanceof HTMLImageElement) {
  - const src = image.src;
  - image = src;
  + image = image.src;
  + }
  + // heatmap layer in geo may be a canvas
  + else if (image instanceof HTMLCanvasElement) {
  + image = image.toDataURL();
  }
  if (!image) {
  return;
  