gtk:print-unix-dialog-manual-capabilities (object)

object -- a gtk:print-unix-dialog widget
capabilities -- a gtk:print-capabilities value for the printing capabilities of the application

The accessor for the manual-capabilities slot. This lets you specify the printing capabilities your application supports. For instance, if you can handle scaling the output then you pass the :scale value. If you do not pass that, then the dialog will only let you select the scale if the printing system automatically handles scaling.