Hi, On Fri, Oct 14, 2005 at 12:20:44AM -0400, Fred Odendaal wrote: > The SANE API defines the sane_control_option as: > > SANE_Status sane_control_option (SANE_Handle h, SANE_Int n, > SANE_Action a, void *v, > SANE_Int * i); > > Where the argument i is used to convey information back to the frontend. > How do I tell the front end to reload options (SANE_INFO_RELOAD_OPTIONS) > when it supplies a null argument for i?
You can't. If the frontend send NULL, it's not interested in reloading the options. > I want to have the user set the y resolution and have the x resolution > automatically update correspondingly. This works for xscanimage, but > not xsane. I'm a bit surprised that xsane send NULL. Are you sure that his is the case? At least for the "normal" options it honors reload requests. If the x resolution directly depends on y, can't you just use one resolution (option "resolution") and set the other one in the backend accordingly? Typically "resolution" means "X resolution". E.g. for most scanners supported by the gt68xx backend you can select these resolutions: Resolution X Y 100 100 100 300 300 300 600 600 600 1200 600 1200 So only one resolution is selected by the frontend and the backend decides which X and Y resolutions it uses. Bye, Henning
