gdk:screen-resolution (object)

object -- a gdk:screen object
dpi -- a double float with the resolution in "dots per inch"

Accessor of the resolution slot of the gdk:screen class. The gdk:screen-resolution function gets the resolution for font handling on the screen, or -1 if no resolution has been set. The (setf gdk:screen-resolution) function sets the resolution for font handling on the screen.

This is a scale factor between points specified in a pango:font-description instance and Cairo units. The default value is 96, meaning that a 10 point font will be 13 units high (10 * 96 / 72 = 13.3).