New global property alpha-background

[omidmnz]

Emacs 29 has introduced alpha-background frame parameter, which I am currently using for transparency. As a result, writeroom-mode no longer toggles transparency for me. I have added the following lines to my configuration to restore the previous toggle behavior

(define-writeroom-global-effect alpha-background 100)
(add-to-list 'writeroom-global-effects 'writeroom-set-alpha-background)

I don't know if it is backwards compatible to add these to the mainwriteroom-modesource, but I think this is the correct behavior in the newer Emacs versions.

[joostkremers]

I think it should be safe to add this, because Emacs should ignore frame parameters that it doesn't know about. I'll have to test it, though.

Thanks for the suggestion.