Notes on Cairo set_source_rgb and set_source_rgba

Noticed three channel values (all non zero) seem to produce a value (255, 255, 255) color which is white.  However two channel values appear to produce their designated colour.   At this point recommend when setting colors that these are done on a two channel basis, i.e., assign no more then two non zero values at any set_sourc_rgb or set_source_rgba call, at a time.

for example, the following arbitrary values should work:
(r,g,b)
(255, 255, 0 ), (178, 89,0), (0, 178, 31), (67, 0, 43), and so forth

but the following doesn't work

(244, 34, 32), (111, 23, 11), and so forth