gnuplot-bugs Mailing List for gnuplot

HI, as I posted here
<https://stackoverflow.com/questions/49763353/gnuplot-how-to-have-only-one-label-of-contour-interval-1-does-ont-work>
:

I am trying to get a 'contour map' of a function of 2 variables. My problem
is that I would like the label to be displayed just once along the contour
set (preferably in the middle of the length of the contour). I tried any
combination of set cntrparam start n interval m (including <0) but I did
not manage to do it (sometimes no label sometimes way too many, but never
only one). I need the sample high enough to get a "smooth" figure...

I tried with this code:

> set isosamples 200,200
> set cntrlabel  format start 50 interval -1 font '.7' onecolor
> set cntrparam levels discrete
> -50,-400,-300,-200,-100,50,20,100,200,300,400,500,0,-20
> set xrange [-5:5]
> set yrange [-5:5]
> set title "Ensembles de niveaux "
> set xlabel " X "
> set ylabel "Y "
> set contour base
> set view map
>
> splot 4*x**3+4*y**3 with lines  lw 3, 4*x**3+4*y**3 with labels point  pointinterval -1
>
> Someone suggested that it might be a bug. Is it ?

Regards,

Laurent Bakri