"Unused bits" seem to be actively used for storing alpha values
I'm using pycairo
. The following problem is probably due to cairo
itself, as discussed here.
The documentation says here for cairo.Format.RGB24
(and here for its equivalent CAIRO_FORMAT_RGB24
) that "the upper 8 bits unused". But looking at them (with numpy
) reveals that they seem to behave like with cairo.Format.ARGB32
, i.e. with different alpha values being written there based on fill()
and stroke()
. So what does "unused" mean, that the values depend on what was easy to implement or fast to run in the current version, and the user shouldn't rely on having any specific values there?
The documentation's claim that the bits are "unused" seems wrong if they might be actively used for storing alpha values.