Return a random floating point number in the range specified, for the given x,y coordinates and GeglRandom provided, if multiple different numbers are needed pass in incrementing n's.
| this |
a GeglRandom |
| x |
x coordinate |
| y |
y coordinate |
| z |
z coordinate (mipmap level) |
| n |
number no (each x,y coordinate provides its own sequence of numbers |
| min |
minimum value |
| max |
maximum value |