Re: master 1555453694: Implement `alpha-background' on non-Cairo builds

[Po Lu]

Jose A Ortega Ruiz <jao@gnu.org> writes:

> let me add that i just tried with emacs compiled with lucid and there
> alpha-background works well with exwm and picom

That shouldn't be possible, since it's disabled on Emacs builds with Xt,
as Xt doesn't really know what to do with a 32-bit visual.  (i.e. Xt
will crash and lwlib will "accidentally" draw things with the alpha
channel set to zero.)

Please evaluate (x-display-planes) in that Emacs build and tell me what
it returns.  Or perhaps you used the old `alpha' frame parameter, which
does work on Xt builds, but also changes the opacity of the foreground
text?

Thanks.