[wxPython-users] GCDC vs DC

[Chris Mellon]

On 8/2/07, Christopher Barker <Chris.Barker at noaa.gov> wrote:
> Christian K wrote:
> > What kind of optimization can be done when using GCDC instead of DC? Do you
> > think wx.lib.plot could be made faster, too?
>
> Probably not. Chris (another one) alluded to this, but I'll try to make
> it more clear.
>
> I'd love to be proved wrong, but in general, it appears that
> wx.GraphicsContext is slower than wx.DC. It's certainly true that GCDC
> is slower.
>
> The optimizations that were referred to was using the raw
> GraphicsContext, rather than GCDC. I don't know that it will ever get
> faster than a native DC but GraphicsContext can give much nicer results
> (and alpha blending, which is very nice)
>
> There would be a lot to be gained by porting pyplot to GraphicsContext,
> but speed is probably not it.
>
> -CHB
>

Drawing using wxGC can be very very fast when you leverage the ability
to re-use paths with  the transforms that wxGC exposes because it lets
you move the math out of python and into the heavily optimized native
implementation. It does, however, require a very different drawing
model. As the underlying platforms move more toward native vector
everything you might even end up with a gain - Gtk in the future is
likely to use cairo for all it's drawing, and raster operations will
be piped through it. Sort of the reverse of the current wxGCDC
penalty.