[Cuis-dev] #redrawNeeded from background processes

Phil B pbpublist at gmail.com
Sat Jun 1 04:05:21 PDT 2019

Every now and then when sending #redrawNeeded from a background process,
you'll probably find you get an 'attempt to index non-existent element in
an ordered collection' error in DamageRecorder.  This is because
DamageRecorder is not thread-safe (OK, process-safe)  I've found this to be
a miserable problem to deal with because even if you're trying to be good
and only message morphs from the UI process, finding all the places/ways
that #redrawNeeded can get called can be tricky if your Morph is updating
based on events from background processes.

The attached changeset fixes that... now you can send #redrawNeeded from
wherever you want, whenever you want. (at least I haven't been able kill it
yet)  This doesn't appear to have any adverse drawing performance impact
that I've been able to measure.

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