Hi,
I just think hsl and hsv should have standard conversions, with hsl2rgb and hsv2rgb functions. I’ve been using a variant on hsl for a while; I like it decently enough, but it’s really slow if you’re doing more than one color; so if we’ll need batches, we’ll need a C version or a numeric package.
def hsl2rgbf( h, s, l ):
'''adapted from wikipedia.org'''
hk= h
if l< 0.5:
q= l* ( 1+ s )
else:
q= l+ s- ( l* s )
p= 2* l- q
tr= hk+ 0.333333
tg= hk
tb= hk- 0.333333
tc= [ tr, tg, tb ]
for c in range( len( tc ) ):
if tc[ c ]< 0:
tc[ c ]+= 1
if tc[ c ]> 1:
tc[ c ]-= 1
cc= [ 0, 0, 0 ]
for c in range( len( tc ) ):
if tc[ c ]< 0.166666:
cc[ c ]= p+ ( ( q- p )* 6* tc[ c ] )
elif tc[ c ]< 0.5:
cc[ c ]= q
elif tc[ c ]< 0.666666:
cc[ c ]= p+ ( ( q- p )* 6* ( 0.666666- tc[ c ] ) )
else:
cc[ c ]= p
cc[ c ]= float( cc[ c ] )
r, g, b= cc
return r, g, b
if __name__== '__main__':
print hsl2rgbf( 0, 0, 0 )
print hsl2rgbf( 0, 0, 1 )
print hsl2rgbf( 0, 1, .5 )This is not official and very ad hoc, and my testing has been on a slight variant that returns 0-255 values.