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.operatorList = IR[2];
    this.matrix = IR[3] || [1, 0, 0, 1, 0, 0];
    this.bbox = IR[4];
    this.xstep = IR[5];
    this.ystep = IR[6];
    this.paintType = IR[7];
    this.tilingType = IR[8];
    this.color = color;
    this.ctx = ctx;
    this.canvasGraphicsFactory = canvasGraphicsFactory;
    this.baseTransform = baseTransform;
  }
  createPatternCanvas(owner) {
    const operatorList = this.operatorList;
    const bbox = this.bbox;
    const xstep = this.xstep;
    const ystep = this.ystep;
    const paintType = this.paintType;
    const tilingType = this.tilingType;
    const color = this.color;
    const canvasGraphicsFactory = this.canvasGraphicsFactory;
    info("TilingType: " + tilingType);