[Kst] extragear/graphics/kst/patches

[George Staikos]

On Monday 31 October 2005 19:38, Barth Netterfield wrote:
> How much speed up do you get?

   This is not easy to judge yet.  It might take a profiler to get meaningful 
results.  Actually, I think the real gain is in lower CPU usage because we're 
blocking on X again.  I've removed almost all the limitations I could find on 
our side now.

> > A patch to implement a short-cut interpolation in the hot spots in curve
> > plotting.  It removes a function call (inlines it) and two branches, one
> > of which has a disjunction, neither of which are likely.  However it's
> > slightly incomplete because it can cause invalid memory accesses if the
> > vectors have size == 1 and it tries to plot them.
> >
> > The easy solution is to
> > plot nothing if one of the vectors has size == 1, but I suspect that's
> > undesired.
>
> We need to be able to plot a single x,y point.

  Originally I was going to implement specifically this case and nothing else, 
but....

> But in 'line' mode, I can't see that we would ever need to plot a curve
> with only one point in one of the vectors.  So we could have two
> interpolates: one for w/ lines and one for w/ points.

  I was thinking of a case of X vector [0,...,n] and Y vector [5] which should 
give a straight line at 5 from 0..n.  Again, we could shortcut this case and 
its complement, but maybe there are other other weird cases too.  The same 
applies to error bars, bar graphs, etc.

-- 
George Staikos
KDE Developer				http://www.kde.org/
Staikos Computing Services Inc.		http://www.staikos.net/