Link to PDF file (or attach file here):
https://issues.apache.org/jira/secure/attachment/12650283/000004_ShadingPatternTextPDF.pdf

Configuration:
- Web browser and its version: FF 51.0.1 32bit
- Operating system and its version: W7
- PDF.js version: latest

Steps to reproduce the problem:
display file

What is the expected behavior? (add screenshot)
![ok](https://cloud.githubusercontent.com/assets/6665575/23339534/5ff2de9c-fc25-11e6-837e-0fdaf81b4ca9.png)

What went wrong? (add screenshot)
![nok](https://cloud.githubusercontent.com/assets/6665575/23339536/63f7a37e-fc25-11e6-813c-cc218cc4def3.png)

possibly similar problem:
https://www.pdflib.com/fileadmin/pdflib/Cookbook/pdf/color_gradient.pdf (shaded text completely missing)
https://issues.apache.org/jira/secure/attachment/12630566/pslib-shading.pdf (page 4, part of text missing)
https://issues.apache.org/jira/secure/attachment/12652009/pattern-shading-2-4-idMatrix.pdf (some text missing)
https://issues.apache.org/jira/secure/attachment/12652010/pattern-shading-2-4-noMatrix.pdf (some text missing)

const scaled = this._scaleImage(imgToPaint, ctx.mozCurrentTransformInverse);
    ctx.imageSmoothingEnabled = getImageSmoothingEnabled(
      ctx.mozCurrentTransform,
      imgData.interpolate
    );
    ctx.drawImage(
      scaled.img,
      0,
      0,
      scaled.paintWidth,
      scaled.paintHeight,
      0,
      -height,
      width,
      height
    );
    if (this.imageLayer) {
      const position = this.getCanvasPosition(0, -height);
      this.imageLayer.appendImage({
        imgData,
        left: position[0],
        top: position[1],
        width: width / ctx.mozCurrentTransformInverse[0],
        height: height / ctx.mozCurrentTransformInverse[3],
      });
    }
    this.compose();
    this.restore();
  }
  paintInlineImageXObjectGroup(imgData, map) {