[PD] range of numbers
Frank Barknecht
fbar at footils.org
Fri Aug 20 23:54:48 CEST 2004
Hallo,
vanDongen/Gilcher hat gesagt: // vanDongen/Gilcher wrote:
> You want to map a range of 0.5 length f.i. starting at 0.1 to another range
> starting at 0 or any other number.
> You do that by
> 1)
> subtract the smallest number (so that is mapped to zero)
You need not necessarily use the smallest number, though. If you want
to invert the input and for example map [127,10] to [20,40] it's
possible as well like this (x is input):
x-127
* (20-40)/(127-10) (ratio of out- and input ranges)
+ 20
although 10 and not 127 would be the smaller number, or more
generally:
(x-il) * (il-ih)/(ol-oh) + ol
and in "expr" form for Pd:
[ expr ($f1-$f2) * ($f4-$f5) / ($f2-$f3) + $f4 ]
using input, from_low, from_hi, to_low, to_high as inlets.
Basically this all is an application of the "rule of three" from
school.
Ciao
--
Frank Barknecht _ ______footils.org__
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