The container HTML element for which the conversion rate should be calculated. This element must have a "width" attribute specifying its width in a different unit. If no "width" attribute is present, no conversion is done.
The current zoom level of the viewer.
If true, calculates the inverse conversion rate; otherwise, calculates the direct conversion rate. The direct conversion rate converts from the unit specified in the "width" attribute to pixels. The inverse conversion rate converts from pixels to the unit specified in the "width" attribute.
The conversion rate indicating the relationship between the units.
Calculate the conversion rate between the width of an element in different measurement units, based on the current zoom level. The element is expected to be a container element with a "width" attribute.