While Firefox and Mozilla have ways to set the print_edge per-printer hardware margins ("Gap from edge of paper to margin"), these remains unsettable using the Galeon UI. The prefs.js file via about:config has global settings for "print.print_edge.bottom", top, left and right, but these have no effect. Other Gekko-based browsers, notably Mozilla and Firefox, have a printer properties dialog which set "print.printer_PostScript/<printer_name>.print_edge_bottom", top, left and right for each printer and these are settable both from the Printer properties UI and from about:config. Copying these lines from the prefs.js file from Firefox or Mozilla into the prefs.js file for Galeon does the Right Thing, and hw margins are set as expected for each printer. It would be very helpful if Galeon could also provide a printer properties dialog to take care of this issue, or at least insert proper default lines into prefs.js when a printer is detected so that they could be set using about:config. This is rather important if one does much printing out of Galeon, and has had me stumped for a long time. The default settings of these are, I think, 0, which puts page header and footer info (date, URL, page, page title) outside the printable area for most printers. Printing online order receipts w.o. a date gets my butt kicked by my bookkeeper, which is a real PITA ;-)
I can't see why this is a gentoo-issue. If you think galeon should have a printer properties dialog, you should report that to the galeon-devs. If you think it should have different default-settings, same thing.
Whatever. If I build something from gentoo and find a problem I always like to give the gentoo devs the first crack at either patching or bumping it upstream. I can do this if you don't want to.