On Wednesday 09 August 2006 15:20, ?tienne Bersac wrote: > Hello, > > > SANE standard 1 does not specify how to handle scanner buttons, > > but it is clear, that an option, which deals with a button has to deliver > > a value (button pressed or not). Regarding that requirement, you have either > > to use SANE_TYPE_BOOL or SANE_TYPE_INT - I choose BOOL. > > SANE_TYPE_BUTTON is maybe misleading. It is intended to be used by a backend > > to allow changes by pressing that button from the GUI and NOT to reflect > > the status of a scanner button. An option of type SANE_TYPE_BUTTON has no > > value. > > See also chapter 4.2.9.4 of the SANE Standard > > http://www.sane-project.org/html/doc011.html > > Okey, the strange part of this button handling is : how an app using > sane know an option reflect a button status ? Just in order to ignore > that option. For example, xsane advanced options dialog shows a fieldset > entitled "Buttons" with one option "Scanner button" which is inactive > and always false. That's useless. I don't know how multiple buttons are > handle. Do the app has to parse name or title or desc field in order to > find a "button" string and then treat the option as a button state > option ? >
checkout the experimental tree of SANE CVS, there's a sample application which does the button handling. XSane is not aware of this "special" handling, and therefore it only displays the button(s). Please keep in mind, that the scanner-button handling is not defined in the SANE standard and more or less inofficial (the avision backend does it the same way) -- Gerhard
