SCGetScannerRes(3)

NAME
     SCGetScannerRes, SCGetMinMaxRes - Determining the resolutions supported
     by a scanner driver

SYNOPSIS
     #include <stdio.h>
     #include <scanner.h>

     int SCGetScannerRes(SCANNER *s, int metric, float **xres,
                         float **yres, int *nres);

     int SCGetMinMaxRes(SCANNER *s, int metric, float *minx, float *miny,
                        float *maxx, float *maxy);

DESCRIPTION
     SCGetScannerRes queries the scanner driver s about the native resolutions
     supported.  These are the resolutions which when used for scanning will
     yield the highest quality image output.

     SCGetScannerRes makes *xres and *yres point to arrays of floating point
     numbers, representing pairs of horizontal and vertical native
     resolutions.  SCGetScannerRes sets *nres to the number of elements in
     each of xres and yres.  metric should be passed in as either SC_INCHES or
     SC_CENTIM, depending on whether the resolution is desired in pixels per
     inch or pixels per centimeter.

     Some scanners support all resolutions within the bounds given by
     SCGetMinMaxRes (see below) equally well.  For such scanners, *nres will
     be 0 after a call to SCGetScannerRes.

     SCGetMinMaxRes fills in *minx with the smallest resolution supported in
     the horizontal direction, *miny with the smallest resolution supported in
     the vertical direction, *maxx with the largest resolution supported in
     the horizontal direction, and *maxy with the largest resolution supported
     in the vertical direction.  Use metric to specify either SC_INCHES or
     SC_CENTIM for the units.

     The scanner driver must support any horizontal resolution between *minx
     and *maxx, and it must support any vertical resolution between *miny and
     *maxy.  Specifying a resolution outside these limits will yield
     unpredictable results.  If the resolution specified is not a resolution
     pair returned by SCScannerRes, image quality may suffer.  See SCSetup(3)
     for more information on setting the scanning resolution.

RETURN VALUE
     SCGetScannerRes and SCGetMinMaxRes return 0 if they are successful, and
     -1 if an error occurs.  If an error does occur, SCerrno will be set to
     indicate the reason for failure.
EXECUTION ERROR CODES
     SCGetScannerRes and SCGetMinMaxRes will fail under the following
     circumstances.

     SCEBADMETRIC             Unsupported metric

     SCEDEV                   Scanner driver error

     SCECOMM                  Error communicating with scanner driver

WARNING
     The memory pointed to by *xres and *yres after a call to SCGetScannerRes
     belongs to libscan(3) and should not be modified by the calling program.
     Nor should any assumptions be made about its values after subsequent
     calls to SCGetScannerRes; in other words, it should be copied to memory
     owned by the calling program before future calls to SCGetScannerRes.

SEE ALSO
     libscan(3), SCSetup(3).