gtk/print.go
func PaperSizeNewCustom(name, displayName string, width, height float64, unit Unit) (*PaperSize, error) {
	cName := C.CString(name)
	defer C.free(unsafe.Pointer(cName))
	cDisplayName := C.CString(displayName)
	defer C.free(unsafe.Pointer(cDisplayName))
	c := C.gtk_paper_size_new_custom((*C.gchar)(cName), (*C.gchar)(cDisplayName),
		C.gdouble(width), C.gdouble(height), C.GtkUnit(unit))
	if c == nil {
		return nil, nilPtrErr
	}
	t := &PaperSize{c}
	runtime.SetFinalizer(t, (*PaperSize).free)
	return t, nil
}
func PaperSizeNewCustom(name, displayName string, width, height float64, unit Unit) (*PaperSize, error) {
	cName := C.CString(name)
	defer C.free(unsafe.Pointer(cName))
	cDisplayName := C.CString(displayName)
	defer C.free(unsafe.Pointer(cDisplayName))
	c := C.gtk_paper_size_new_custom((*C.gchar)(cName), (*C.gchar)(cDisplayName),
		C.gdouble(width), C.gdouble(height), C.GtkUnit(unit))
	if c == nil {
		return nil, nilPtrErr
	}
	t := &PaperSize{c}
	runtime.SetFinalizer(t, (*PaperSize).free)
	return t, nil
}
// PaperSizeNewCustom() is a wrapper around gtk_paper_size_new_custom().