Hi,
On Thu, Nov 09, 2000 at 06:32:16PM +0800, kwlee wrote:
> :( this option of course no need by high-end scanner, but seems "must"
> for low cost scanner to get consistent quality.
Don't get me wrong. I am not saying that the warm-up is not necessary.
> Normally, the lamp reach stable stage will need 1.5 minutes(in my memory)
> but reach 95% stable will only need about 30 seconds, so most of time
> we use 30 secs as warm-up count down, but you know no matter 1.5 minutes
> or 30 secs waiting, users can not tolerate without any prompting message,
> they maybe thinking your scanner hang-up again, counting down will make
> them believe their scanner is still alive.
I see. So maybe we can just add some sort of callback mechanism
(pseudocode):
SANE_Status
sane_set_message_callback (message_call_back_function_pointer m)
So with using this, the frontend tells the backend that it can handle
messages.
In the backend:
return_value = m ("backend name", "message", "yes", "no");
So the frontend can pop up a message and return the option the user
selected.
In your case you could pop up the message "Remaining time for warm-up:
xx seconds. Do you want to scan immediately or wait for warm-up?"
As a work-around for sane 1 you could at least print out some messages
with DBG(0, "waiting for warm-up (xxx seconds left).").
> for example, scanner scaned in jpeg mode, but user hope to save as
> pnm or tif format(this could save many scan time), in such case what
> will you thinking ?
Both (frontend and backend) are possible. I don't know too much about
the image formats and convertion, so maybe someone else can answer to
this.
Bye,
Henning
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