message: text: background alpha handling when calculating default outside stroke
diff: @@ -621,9 +621,14 @@ class Element<Props extends ElementProps = ElementProps> {
  const backgroundColor = this.__zr && this.__zr.getBackgroundColor();
  let colorArr = typeof backgroundColor === 'string' && parse(backgroundColor as string);
  if (!colorArr) {
  - colorArr = [255, 255, 255, 0.8];
  + colorArr = [255, 255, 255, 1];
  }
  - colorArr[3] = 0.8;
  + // Assume blending on a white background.
  + const alpha = colorArr[3];
  + for (let i = 0; i < 3; i++) {
  + colorArr[i] = colorArr[i] * alpha + 255 * (1 - alpha);
  + }
  + colorArr[3] = 1;
  return stringify(colorArr, 'rgba');
  }
  