[PD-dev] tcl/tk 8.5, antialising, and large fonts lead to huge cpu overhead bug?

[Hans-Christoph Steiner]

Sounds like you are charting new territory.  I haven't worked with  
Tcl/Tk 8.5 yet, but I think a couple people on the list have.

I don't know of any reason to update a GUI object more than 100 Hz  
since that's about the max for screen refreshes.  10 Hz is probably  
faster than we can perceive numbers anyway.

.hc

On Feb 18, 2007, at 11:03 PM, ico at vt.edu wrote:

> All right, unlike my previous e-mail this is perhaps not a bug, but  
> an oddity.
> Nonetheless, it would be nice to know at least where it is stemming  
> from so
> that I can contribute code in the right place...
>
> I've encountered unusual spike in cpu use when using antialiased  
> tcl/tk 8.5
> (IIRC it also affects other antialiasing-enabled tcl/tk releases) in
> conjunction with large fonts. I for instance use this for my  
> performers so that
> they can clearly read info even when positioned at some distance  
> from the
> display monitor/LCD.
>
> One quick example would be to use a large font counter which counts  
> 1/100ths of
> a second using metro and displaying it in a number2 object. This  
> results in a
> 80+% (!) CPU utilization on an Athlon 64 3000+. Lowering metro to  
> 1/10th of
> second drops CPU use below 5%. Similarly making font smaller does  
> the same.
> Font size used is in this case is just about anything above 72.
>
> Any ideas how to circumvent this problem? Is this due to antialiasing
> inefficiency in tcl/tk or some other reason? If I can be pointed in  
> the right
> direction, I'll gladly provide patches...
>
> Best wishes,
>
> Ivica Ico Bukvic, D.M.A.
> Composition, Music Technology, CCTAD, CHCI
> Virginia Tech
> Department of Music
> Blacksburg, VA 24061-240
> (540) 231-1137
> (540) 231-5034 (fax)
> ico.bukvic.net
>
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> PD-dev mailing list
> PD-dev at iem.at
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