Ideas for a grayscale library

Controller:
SSD132x		4 Bit, 16 Level
SSD1327		4 Bit, 16 Level			Variant B/16H
SSD1327		4 Bit, 16 Level			Variant B/16H
SSD1329		4 Bit, 16 Level			Variant B/16H
UC1610		2 Bit, 4 Level			Variant 4V
UC1611		4 Bit, 16 Level			Variant A/16V
UC1617		2 Bit, 4 Level			Variant 4H???
UC1638		2 Bit, 4 Level			Variant 4V
ST75256		2 Bit, 4 Level			Variant 4V



======================

Variant A:

Memory:
aaaabbbb
ccccdddd

aaaa: 0,0
bbbb: 0,1
cccc: 1, 0
dddd: 1,1

======================

Variant B:

Memory:
aaaabbbb
ccccdddd

aaaa: 0,0
bbbb: 1,0
cccc: 0, 1
dddd: 1,1

======================

Variant 4V:

Memory:
aabbccdd
eeffgghh

aa: 0,0
bb: 0,1
cc: 0,2
dd: 0,3
ee: 1,0
ff: 1,1
gg: 1,2
hh: 1,3