#include <matdef.h>contour (a, nx, ny, z, nc, xmin, ymin, xmax, ymax, lineto) real *a, z[], xmin, ymin, xmax, ymax; int nx, ny, nc; proc lineto; contour_setdet(mode,value) int mode; real value; Descriptioncontour expects a two dimensional matrix, contiguous in memory in either C or FORTRAN definition (matdef(5NEMO)), pointed to by a. The size of the matrix is nx by ny pixels. There must be nc sorted contour levels supplied in the array z. The Plotting area is from xmin,ymin to xmax,ymax. contour needs external relocate(x,y) and draw() routines which do the actual line drawing. In NEMO can be supplied by the yapp(3NEMO) interface, or have to defined in the calling program. In such the linestyle of the contours can be externally set. An externally defined function void lineto(real x0, real y0, real x1, real y1) must be supplied to provide the transformation from world to plot coordinates, since contour has no knowledge of the plotting world. contour_setdef defines if contours need to ignore points which are near undefined value. If mode=1, the value will be taken as the undefined value. When this routine is never called contour doesn’t know about undefined value, i.e. mode=0. BugsContour levels must be sorted in increasing order. The MATDEF stuff could mirror your images if not used consistently. AuthorPeter Teuben Files ~/src/image/misc contour.c
xx-jun-87 original version PJT 1-feb-89 FORDEF/CDEF implemented - PJT 10-sep-90 Added routine contour_setdef PJT 6-may-95 new contour() with lineto now formally in NEMO PJT