gdk::pixmap_create_from_xpm() returns a array consisting of a GdkPixmap and a GdkBitmap mask that has been created from the specified pixmap data given by the array.

The array has to have the same structure like the "normal" C-array in an xpm file.

$gdkpixmap = gdk::pixmap_create_from_xpm_d($main_window->window, $transparent_color, $data);

The transparent_color determines what color the None pixels will get if you don't use the pixmask.

See the tutorial for more details and some examples.