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

[ico at vt.edu]

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