read-only
The linear scale factor for drawing this image at its intended size.
The scale factor applies to the width and the height.
For example, if this is 2.0 it means that there are four image pixels for
every one logical pixel, and the image's actual width and height (as given
by the ui.Image.width and ui.Image.height properties) are double the
height and width that should be used when painting the image (e.g. in the
arguments given to Canvas.drawImage).