NAME
       im_grey, im_fgrey, im_make_xy - creates a grey scale
SYNOPSIS
       #include <vips/vips.h>
       int im_grey( image, xsize, ysize )
       IMAGE *image;
       int xsize, ysize;
       int im_fgrey( image, xsize, ysize )
       IMAGE *image;
       int xsize, ysize;
       int im_make_xy( image, xsize, ysize )
       IMAGE *image;
       int xsize, ysize;
DESCRIPTION
       im_grey(3)  creates a one-band FMTUCHAR grey scale image of sizes xsize
       by ysize.  The intensity varies from 0 (left) to 255 (right).
       im_fgrey(3) works as  im_grey(3),  except  that  the  output  image  is
       FMTFLOAT, allowing pixel values from 0 (left) to 1.0 (right).
       im_make_xy(3) makes a two-band FMTUINT image where each pixel in band 0
       has a value equal to the x coordinate, and each pixel in band 1  has  a
       value equal to the y coordinate.
RETURN VALUE
       The function returns 0 on success and -1 on error.
SEE ALSO
       im_black(3)
COPYRIGHT
       Birkbeck College and the National Gallery, 1995
                                  10 May 1991