[linux-audio-dev] FLTK/X11 question

[Steve Harris]

Sorry, this is not directly audio related.

I'm hacking together a VU meter app for jack, using FLTK, and it works OK,
except that when the update rate falls out of sync with the video refresh
rate the window flickers. I'm pasting a bigass image as the background,
see screenshot http://inanna.ecs.soton.ac.uk/~swh/vu-ss.png (apologies
for the tacky brushed steel background, its a placholder, honest).

I seem to remeber that on the Amiga and in GL I could issue a call to wait
for the next vertical blank, forcing the redraw to be in sync with the
video hardware. Is there an equivalent in FLTK or X?

How do other people get round this?

Cheers,
   Steve

PS I know a VU meter in a PCM system is about as much use as an underwater
   hairdryer, but its a stepping stone to a PPM meter, and you can run it
   in peak mode, but with a VU scale and balistics.