pango:cairo-context-resolution (context)

context -- a pango:context object, from a PangoCairo font map
dpi -- a number coerced to a double float for the resolution in dots per inch, physical inches are not actually involved, the terminology is conventional, a 0 or negative value means to use the resolution from the font map

Gets or sets the resolution for the Pango context. 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, that is (10 * 96 / 72 = 13.3).