Hi, On Fri, Jul 09, 2004 at 09:45:03AM -0400, m. allan noah wrote: > > Hm - maybe callback stuff are too much changes for 1.x - maybe we > > should finally start working on SANE 2? > > can we do callbacks via options? thinking about a gui front-end: > > what about an 'led' that is red while the lamp is off, yellow when > warming, and green when it is hot. this could be done via a read-only > option that has a polling capability set. the front end could just loop > thru all the options with poll set, and change the interface. if you gave > that option a well-known name, like 'lamp-status' then the front-ends > could do majic things like wait for it to become ready before displaying > the scan button.
That's an idea I like. > > In my last mail I already wrote that the HP 74xx have buttons to > > change the scan mode and copy count - this are also use cases where > > the "option changed" callbacks come handy. > > can you think of a case where a call-back is required? (i want to avoid > them, if possible.) "Warm up time 30 seconds - [BUTTON: Cancel]". E.g. if you know that the scanner is already warmed up. In this case a more intelligent warm-up code may be better :-) Bye, Henning
