off by 1 error?
dmj.ccc at gmail.com
Fri Apr 9 22:10:29 CEST 2010
I'm trying to assign a color to various values between some arbitrary
maximum and minimum, and i'd like to go from red to blue to green .
Currently, I have the following, where i'm passing the minimum and
maximum as a 2-tuple:
def getcolor( minmax, curr ):
rangesize = (minmax - minmax) - 1
currsize = float( curr - minmax )
currpos = currsize / rangesize
colornum = int( currpos*511 + 0.5 )
r = max( 255 - colornum, 0 )
g = max( -256 + colornum, 0 )
b = 255 - ( r+g )
1) is there a better way to do this?
2) at the extreme points, this doesn't work: the number of (255, 0,
0)s and (0, 255, 0)s are 1/2 what they should be, and (0, 0, 255) is
double what it should be.
the above algorithm at least doesn't give me things like (0, -1, 256),
which i struggled with for a while, but where is/are my off-by-one(s)?
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