[sane-devel] problem setting custom resolution

[aneesh m raj]

Hi,
This is the resolution range value
Rang min:4915200
Range max:78643200
This is in FIXED format when I UNFIX it I''l get 75 and 1200
The user will set the resolution in UNFIXED form  in the range 75 to 1200
When I set the resolution I'll convert the value by
if (opt->type == SANE_TYPE_FIXED)
    d = strtod (option, &end) * (1 << SANE_FIXED_SCALE_SHIFT);
and after that I'll set the option

I'm I doing right....the problem is the scanner wont scan...seems like it is
getting jammed.
Regards
Aneesh

----- Original Message -----
From: "Henning Meier-Geinitz" <henning at meier-geinitz.de>
To: <sane-devel at www.mostang.com>
Sent: Friday, August 22, 2003 11:33 AM
Subject: Re: [sane-devel] problem setting custom resolution


> Hi,
>
> On Tue, Sep 23, 2003 at 10:34:13AM +0530, aneesh m raj wrote:
> > Im trying to read the scanned data using sane form UMAX 2000p but
> > when i set a custom resolution the read is causing some problem. This
> > is my code.
>
> Which problem exactly? Does it work with other frontends?
>
> The code looks mostly ok for me, only some error checking for
NULL-pointers
> is missing. And be careful not to create buffer overflows with strcpy.
>
> You should put sane_start inside the outer "do" loop if this loop is
> intended for multi-pass scanning.
>
> >   do
> >   {
> >
> >     status = read_data(devHnd, buffer, MAX_LEN, &len);
> >     if(status == SANE_STATUS_GOOD )
> >      {
> >
> >       fwrite(buffer,len,sizeof(SANE_Byte),fp);
> >      }
> >     else if(status != SANE_STATUS_EOF)
> >     {
> >
> >       set_error(act);
> >       printf("Reading scanned data failed...\n");
> >     }
> >     free(buffer);
> >     buffer = (SANE_Byte*)malloc(sizeof(SANE_Byte) * MAX_LEN);
>
> I don't understand why you free the buffer and malloc it right again.
>
>
> >   }while( status == SANE_STATUS_GOOD && len != 0);
>
> len can be 0 when you called sane_set_io_mode and set the io_mode to
> non-blocking.
>
> >   if( status == SANE_STATUS_EOF)
> >   {
> >     pthread_cond_signal(&pollevent);
> >     printf("Reading complete...\n");
> >   }
> >   else
> >   {
> >     pthread_cond_signal(&pollevent);
> >     ret = 1;
> >     set_error(act);
> >     printf("Reason: %s",(char*)sane_strstatus(status));
> >   }
>
> If you get an error here, I'd leave the "do" loop. It doesn't really
> make sense to try to read the other frames if reading one of them
> resulted in an error.
>
> > any help is appreciated
>
> How do you set the resolution? To which value? How does read_data()
> look like?
>
> Bye,
>   Henning
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