Attach (recommended) or Link to PDF file here:
issue13500 (in test corpus)

This regressed when landing #13566. 

What is the expected behavior? (add screenshot)
<img width="664" alt="image" src="https://user-images.githubusercontent.com/942640/122467522-7bc8aa80-cf6f-11eb-9d4d-311eb7c64fb2.png">


What went wrong? (add screenshot)
![image](https://user-images.githubusercontent.com/942640/122467565-85eaa900-cf6f-11eb-9c10-8a8686ed440c.png)


startColor = startColor ? startColor[$toStyle]() : "#FFFFFF";
    const endColor = this.color ? this.color[$toStyle]() : "#000000";
    const width = 5;
    const cmd = "repeating-linear-gradient";
    const colors = `${startColor},${startColor} ${width}px,${endColor} ${width}px,${endColor} ${
      2 * width
    }px`;
    switch (this.type) {
      case "crossHatch":
        return `${cmd}(to top,${colors}) ${cmd}(to right,${colors})`;
      case "crossDiagonal":
        return `${cmd}(45deg,${colors}) ${cmd}(-45deg,${colors})`;
      case "diagonalLeft":
        return `${cmd}(45deg,${colors})`;
      case "diagonalRight":
        return `${cmd}(-45deg,${colors})`;
      case "horizontal":
        return `${cmd}(to top,${colors})`;
      case "vertical":
        return `${cmd}(to right,${colors})`;
    }
    return "";
  }
}
class Picture extends StringObject {