Is it possible to use a function to calculate the real tic values based on the auto generated tic values in colorbox

Question

I want to use a function to calculate the real tic value based its automatically generated value.

Here is the example:

set pm3d;
set pm3d map;
splot x*y;

It gives:

I want to use a function f(x)=x^2 to calculate the real tic values for the color box based on its automatically generated tic values: 100, 50, 0, -50, -100. Then the displayed values should be 10000, 2500, 0, 2500, 10000.

If it is difficult to deal with repeated 2500 and 10000, a solution to generate only half the legend values: 10000, 2500, 0 would also help.

Thanks.

Answer 1

You can replace the automatically generated cbtics with set cbtics add ...:

set pm3d map
f(x) = x**2
set for [i=-100:100:50] cbtics add (sprintf('%d', f(i)) i)
splot x*y

But this solution assumes, that you know the values of the automatic cbtics.