Re: [Plib-devel] Proposed change to PuDial

[Steve B. <sjb...@ai...>]

Steve Baker wrote:
> 
> Norman Vine wrote:
> >
> > Hi All
> >
> > I have been experimenting with a version of PuDial that stashes
> > the sin and cosine for the circle drawing.  It seems to work well
> > and I can't think of a case where it would break any existing code
> > but I do precompute the transcendentals in the constructor so this
> > could cause a problem if the dial was to ever change size ( radius )
> 
> <snip>
> 
> > Should I commit this ?
> 
> Yes - sounds good to me.  If the computation of the points were
> in a private member function, it shouldn't be too hard to call that
> if ever the size changes.

<steve finishes first coffee of day and wakes up a little>

...or...

Why not just precompute the trancendentals *only* and do the
'multiply-by-the-radius' step in realtime?

That should get us back *most* of the computation time that your original
idea saved - but because the table is now independent of the radius,
it doesn't change when the widget is resized.

More than that, you now only need one table for *all* puDials instead
of a separate table for *each* puDial - so it can be pre-computed and
stored as a pre-initialised static array inside puDial.cxx

----------------------------- Steve Baker -------------------------------
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