Question about <primitive:127>

Lex Spoon lex at cc.gatech.edu
Mon Dec 11 08:40:31 UTC 2000



> I've been testing with self changed instead of the displayAt: and found
> that while self changed executes
> allot faster than displayAt: it shows a lower frame rate at the screen,
> since it does not force a screen
> update. I have not looked into how self changed is implemented, but
> maybe if I could mark the 
> self changed as critical so changes was more frequent. That way there
> would not be two 
> competing Squeak processes fighting for screen update. 
> 

"self changed" doesn't do much itself; it just arranges that the morph
will get redrawn via drawOn:, eventually.  If you write a custom drawOn:
method which uses drawImage:at: instead of paintImage:at:, you'd
probably see about the same speedup that drawing directly on Display
gets you.


By the way, have you checked on the speed of #forceToScreen:?  That will
be a lower bound on the time it takes to display a frame.  Likewise, it
would be interesting to test how long just *decoding* a typical MPEG
file takes, if you don't simultaneously display it.


-Lex





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