message: feat(svg): support exporting base64-encoded dataURL.
diff: @@ -339,10 +339,12 @@ class SVGPainter implements PainterBase {
  }
  this._oldVNode = null;
  }
  - toDataURL() {
  - const str = this.renderToString();
  - const html = encodeURIComponent(str);
  - return 'data:image/svg+xml;charset=UTF-8,' + html;
  + toDataURL(base64?: boolean) {
  + const str = encodeURIComponent(this.renderToString());
  + const prefix = 'data:image/svg+xml;';
  + return base64
  + ? prefix + 'base64,' + window.btoa(unescape(str))
  + : prefix + 'charset=UTF-8,' + str;
  }
  refreshHover = createMethodNotSupport('refreshHover') as PainterBase['refreshHover'];
  