This page just demonstrates two things:
Smoothing: Bezier curves that pass through all sampled points
Stroke width is determined by using distance between measured points as a proxy for the mouse velocity at the time the signature was created.
Resizing: This signature also resizes if you refresh or resize the browser window.
This finds the largest intersection of the recording canvas and rendering canvas, maps the recorded signature points to that new canvas, then centers it to generate a scaled, centered signature.
Smoothing: Straight line segments between sampled signature points (original)
The original method creates straight lines and kinks between the sampled points.
Resizing: The data is saved as a (x,y) coordinates from the top left corner of the canvas, measured in pixels.
As a result, if you regenerate the signature on a canvas that is smaller than the canvas on which the signature was recorded, the signature will render off the canvas.