Printing under Unix has always been a cause of problems as Unix does not provide a standard way to display text and graphics on screen and print it to a printer using the same application programming interface - instead, displaying on screen is done via the X11 library while printing has to be done with using PostScript commands. This was particularly difficult to handle for the case of fonts with the result that only a selected number of application could offer WYSIWYG under Unix. Equally, wxWidgets offered its own printing implementation using PostScript which never really matched the screen display.
Starting with version 2.8.X, the GNOME project provides printing support through the libgnomeprint and libgnomeprintui libraries by which especially the font problem is mostly solved. Beginning with version 2.5.4, the GTK+ port of wxWidgets can make use of these libraries if wxWidgets is configured accordingly and if the libraries are present. You need to configure wxWidgets with the configure --with-gnomeprint switch and your application will then search for the GNOME print libraries at runtime. If they are found, printing will be done through these, otherwise the application will fall back to the old PostScript printing code. Note that the application will not require the GNOME print libraries to be installed in order to run (there will be no dependency on these libraries).
In version GTK+ 2.10, support for printing has finally been added to GTK+ itself. Support for this has yet to be written for wxGTK (which requires drawing through Cairo).