Map reverse ranges

Can the map command be used to “reverse ranges”. What I mean is can a value in the range 0-10 be mapped to 255-0? I.e., if x=2, then map(2,0,10,255,0) would return 205.

Yes. Did you try it?

Looks like it should work.

map (from WMath.cpp) is just:

long map(long x, long in_min, long in_max, long out_min, long out_max)
{
  return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}

Yes that works,

Please not that if you have a 0 in the map parameter list the formula becomes simpler. Two 0's even more simple. That could be important if you need performance.

x = map(2, 0, 10, 255, 0) // spaces makes it better readable

==>

x = 255 - 10 * 25.5;

If performance is an issue, you might have a look at my fastmap class, that does some precalculations to minimize the math esp. remove the "expensive" divisions from code.