NAME
       im_line - writes a line on a vasari image
SYNOPSIS
       #include <vips/vips.h>
       int im_line(image, x1, y1, x2, y2, pelval)
       IMAGE *image;
       int x1, x2, y1, y2, pelval;
DESCRIPTION
       im_line()  draws  a  line in the image held by image.  The start of the
       line is at point (x1,y1) and the end is at (x2,y2).  The  intensity  of
       the  drawn  line  is  pelval.   Input image should be one byte unsigned
       char.  The function overwrites any data in the file, so take care  when
       applying it.
       This   function   is  here  for  compatibility  only.  You  should  use
       im_fastline(3) or im_fastlineuser(3).
RETURN VALUE
       The function returns 0 on success and -1 on error.
SEE ALSO
       im_grey(3), im_fastline(3).
COPYRIGHT
       N. Dessipris
AUTHOR
       N. Dessipris - 10/05/1991
                                  10 May 1991