PDF.js displays blurry plots in PDF documents, e.g.

http://arxiv.org/pdf/1202.5344v1.pdf

When viewed in Chrome or Adobe Acrobat all the plots show sharp-edged squares. When viewed in Preview or PDF.js, all the squares show as blurry pixelated blobs.

this.current.strokeColor = this.getColorN_Pattern(arguments);
    }
    setFillColorN() {
      this.current.fillColor = this.getColorN_Pattern(arguments);
      this.current.patternFill = true;
    }
    setStrokeRGBColor(r, g, b) {
      const color = Util.makeHexColor(r, g, b);
      this.ctx.strokeStyle = color;
      this.current.strokeColor = color;
    }
    setFillRGBColor(r, g, b) {
      const color = Util.makeHexColor(r, g, b);
      this.ctx.fillStyle = color;
      this.current.fillColor = color;
      this.current.patternFill = false;
    }
    shadingFill(patternIR) {
      if (!this.contentVisible) {
        return;
      }
      const ctx = this.ctx;
      this.save();
      const pattern = getShadingPattern(patternIR);