[Cuis-dev] #redrawNeeded from background processes

Juan Vuletich juan at jvuletich.org
Mon Jun 3 07:08:12 PDT 2019

On 6/1/2019 8:05 AM, Phil B via Cuis-dev wrote:
> 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.
> Thanks,
> Phil

Oh! That was a nasty bug! Your fix is now @ GitHub (together with 
updated images).

Thank you!

Juan Vuletich

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