Attach (recommended) or Link to PDF file here:
[PATTYP2.pdf](https://github.com/mozilla/pdf.js/files/6471935/PATTYP2.pdf)

Configuration:
- Web browser and its version: FF 88.0.1
- Operating system and its version: W10.0.19042.985
- PDF.js version: https://mozilla.github.io/pdf.js/web/viewer.html

Steps to reproduce the problem:
1. open file to display

What is the expected behavior? (add screenshot)
![grafik](https://user-images.githubusercontent.com/6665575/118114800-5e407800-b3e8-11eb-860f-019f48a8eabf.png)

What went wrong? (add screenshot)
![grafik](https://user-images.githubusercontent.com/6665575/118114841-6c8e9400-b3e8-11eb-8252-1517e5d76475.png)

(memo for me: when fixed, check the files in https://issues.apache.org/jira/browse/PDFBOX-1958 )

const context = graphics.ctx,
      current = graphics.current;
    switch (paintType) {
      case PaintType.COLORED:
        const ctx = this.ctx;
        context.fillStyle = ctx.fillStyle;
        context.strokeStyle = ctx.strokeStyle;
        current.fillColor = ctx.fillStyle;
        current.strokeColor = ctx.strokeStyle;
        break;
      case PaintType.UNCOLORED:
        const cssColor = Util.makeHexColor(color[0], color[1], color[2]);
        context.fillStyle = cssColor;
        context.strokeStyle = cssColor;
        
        current.fillColor = cssColor;
        current.strokeColor = cssColor;
        break;
      default:
        throw new FormatError(`Unsupported paint type: ${paintType}`);
    }
  }
  getPattern(ctx, owner, shadingFill) {