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.setLeading(-y);
      this.moveText(x, y);
    }
    setTextMatrix(a, b, c, d, e, f) {
      this.current.textMatrix = [a, b, c, d, e, f];
      this.current.textMatrixScale = Math.hypot(a, b);
      this.current.x = this.current.lineX = 0;
      this.current.y = this.current.lineY = 0;
    }
    nextLine() {
      this.moveText(0, this.current.leading);
    }
    paintChar(character, x, y, patternTransform, resetLineWidthToOne) {
      const ctx = this.ctx;
      const current = this.current;
      const font = current.font;
      const textRenderingMode = current.textRenderingMode;
      const fontSize = current.fontSize / current.fontSizeScale;
      const fillStrokeMode =
        textRenderingMode & TextRenderingMode.FILL_STROKE_MASK;
      const isAddToPathSet = !!(
        textRenderingMode & TextRenderingMode.ADD_TO_PATH_FLAG
      );
      const patternFill = current.patternFill && !font.missingFile;
      let addToPath;
      if (font.disableFontFace || isAddToPathSet || patternFill) {
        addToPath = font.getPathGenerator(this.commonObjs, character);
      }