I'm sorry if it's a duplicate, I found lots of issues with gradients but none of the open ones looks similar.
It's apparently the PDF code `/Matrix [440 0 0 -200 20 220]` (line 44 in both files) that causes the problem.

**Configuration:**
- Web browser and its version: Chrome 54
- Operating system and its version: Windows 10
- PDF.js version: 1.6.343

**Steps to reproduce the problem:**
Open attached files:
[radial.pdf](https://github.com/mozilla/pdf.js/files/610302/radial.pdf)
[linear.pdf](https://github.com/mozilla/pdf.js/files/610300/linear.pdf)

**What is the expected behavior?** (Adobe Reader 11)
![image](https://cloud.githubusercontent.com/assets/17966696/20583379/fa80d780-b1f1-11e6-85d2-62dd6970a08c.png)

**What went wrong?** (mozilla.github.io/pdf.js/web/viewer.html)
Gradients aren't correctly transformed
![image](https://cloud.githubusercontent.com/assets/17966696/20583361/cf5bb8a4-b1f1-11e6-9479-9cc606b41187.png)

unreachable("Should not call beginImageData");
    }
    paintFormXObjectBegin(matrix, bbox) {
      if (!this.contentVisible) {
        return;
      }
      this.save();
      this.baseTransformStack.push(this.baseTransform);
      if (Array.isArray(matrix) && matrix.length === 6) {
        this.transform.apply(this, matrix);
      }
      this.baseTransform = this.ctx.mozCurrentTransform;
      if (bbox) {
        const width = bbox[2] - bbox[0];
        const height = bbox[3] - bbox[1];
        this.ctx.rect(bbox[0], bbox[1], width, height);
        this.clip();
        this.endPath();
      }
    }
    paintFormXObjectEnd() {
      if (!this.contentVisible) {
        return;
      }
      this.restore();
      this.baseTransform = this.baseTransformStack.pop();
    }
    beginGroup(group) {