Steps to reproduce the problem:
1. When using the demo application - https://mozilla.github.io/pdf.js/web/viewer.html, load  the document 5311693-1.pdf

[5311693-1.pdf](https://github.com/mozilla/pdf.js/files/5137225/5311693-1.pdf)

2. go to Page 16 of the document.

3.  The strip of  EKG data  appears to have an incorrect line width   under the  Multi-color heat rate chart.

4.  When the same document is generated by pdffactory ,  the artifact are not visible.

What is the expected behavior? (add screenshot)
![expected](https://user-images.githubusercontent.com/3577617/91461157-4622cb80-e84e-11ea-8e5d-750c7b4e64ae.PNG)

What went wrong? (add screenshot)
The EKG line strip  has an incorrect thickness.  the x-transform seems to stretch the line thickness.  See the  stri in the RED rectagngle of the attached behavior versus the GREEN rectangle

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):
 https://mozilla.github.io/pdf.js/web/viewer.html
width,
        height
      );
      if (this.imageLayer) {
        const position = this.getCanvasPosition(0, -height);
        this.imageLayer.appendImage({
          imgData,
          left: position[0],
          top: position[1],
          width: width / currentTransform[0],
          height: height / currentTransform[3],
        });
      }
      this.restore();
    },
    paintInlineImageXObjectGroup: function CanvasGraphics_paintInlineImageXObjectGroup(
      imgData,
      map
    ) {
      if (!this.contentVisible) {
        return;
      }
      const ctx = this.ctx;
      const w = imgData.width;
      const h = imgData.height;
      const tmpCanvas = this.cachedCanvases.getCanvas("inlineImage", w, h);
      const tmpCtx = tmpCanvas.context;
      putBinaryImageData(tmpCtx, imgData, this.current.transferMaps);
      for (let i = 0, ii = map.length; i < ii; i++) {
        const entry = map[i];