lvsamp(3)           University of New Mexico            lvsamp(3)



LIBRARY ROUTINE
     lvsamp - Sample an image along an arbitrary line.

LIBRARY CALL
          #include "vinclude.h"
          int lvsamp(image,line,x1,y1,x2,y2,n)
          struct xvimage *image,**line;
          int x1,y1,x2,y2,n;

INPUT
     image          pointer to image to be sampled

     line           pointer to image pointer to receive the  out-
                    put image

     x1             X coordinate of start point

     y1             Y coordinate of start point

     x2             X coordinate of end point

     y2             Y coordinate of end point

     n              number of samples  to  generate  between  the
                    endpoints

OUTPUT
     line           xvimage pointer indicated by line is attached
                    to the new image

MODIFICATIONS
     6-Feb-91 Scott Wilson - Cleaned up  for  installation,  com-
     pleted documentation.

     8-Feb-91 Scott Wilson - changed length  to  n,  added  pixel
     size stuff.

     10-Feb-91 Scott Wilson -re-wrote the entire inner loop - the
     original  had  bugs  and  did not handle the boundary condi-
     tions.

     20-Feb-91 Scott Wilson - corrected  pixel  size  computation
     bug.

DESCRIPTION
     Given an image of arbitrary size and  a  line  through  that
     image, sample the image along the line.  The sampling inter-
     val is independent of image size and line  orientation.  The
     value  at each sample point is obtained by bilinear interpo-
     lation.





7/91                    Last change: 03/                        1






lvsamp(3)           University of New Mexico            lvsamp(3)



     The first sample point is precisely at  the  starting  point
     and the final sample is precisely at the ending point.

SEE ALSO
     vsamp(1), intro(3), vipl(3), verror(3), vutils(3)


RESTRICTIONS
     _l_v_s_a_m_p will only work on images of type FLOAT.

AUTHOR
     Richard Krukar


COPYRIGHT
     Copyright  1991,  University  of  New  Mexico.   All  rights
     reserved.






































7/91                    Last change: 03/                        2