PaperSize 
    GtkPaperSize handles paper sizes.
It uses the standard called PWG 5101.1-2002 PWG: Standard for Media Standardized Names to name the paper sizes (and to get the data for the page sizes). In addition to standard paper sizes, GtkPaperSize allows to construct custom paper sizes with arbitrary dimensions.
The GtkPaperSize object stores not only the dimensions (width and height) of a paper size and its name, it also provides default print margins.
Constructors
Creates a new GtkPaperSize object by parsing a PWG 5101.1-2002 paper name.
Creates a new GtkPaperSize object with the given parameters.
Deserialize a paper size from a GVariant.
Creates a new GtkPaperSize object by using IPP information.
Reads a paper size from the group @group_name in the key file
Creates a new GtkPaperSize object by using PPD information.
Functions
Gets the default bottom margin for the GtkPaperSize.
Gets the default left margin for the GtkPaperSize.
Gets the default right margin for the GtkPaperSize.
Gets the default top margin for the GtkPaperSize.
Gets the human-readable name of the GtkPaperSize.
Gets the PPD name of the GtkPaperSize, which may be null.
Serialize a paper size to an a{sv} variant.