Saving the cairo context won't help you for performance of a plot with lots
of point. What you may want to do if memory is more available than CPU is to
cache the image that you draw on, and then just show the image next time you
have an expose event. There might actually be some functionality in gtk to
do this automatically...
Regards,
Dov
2008/5/15 Diego A. Fons <[EMAIL PROTECTED]>:
> Paul Davis wrote:
> > On Thu, 2008-05-15 at 12:05 -0300, Diego A. Fons wrote:
> >
> >
> >> Like Theodore I'm using gtkmm. This is an extrac of the code which
> >> doesn't work:
> >> void Plotter::on_realize( void )
> >> {
> >> // Create the GDK window
> >> refGdkWindow = Gdk::Window::create(get_window(), &attributes,
> >> GDK_WA_X | GDK_WA_Y);
> >>
> >> // Create Cairo context
> >> Cairo::RefPtr<Cairo::Context> cr =
> refGdkWindow->create_cairo_context();
> >> }
> >>
> >
> > you're all thinking too hard. Cairo drawing contexts are supposed to be
> > created as necessary. They are cheap. Don't try to cache them. Create
> > them in an expose handler and get rid of them.
> >
> > my attitude towards Cairo is to assume that its been handcoded in SSE9
> > assembler unless i come across particular hotspots.
> >
> >
> >
> So you are saying I create the Cairo context in the expose event and
> don't care about performance of redrawing the whole plot? OK, I'm trying
> that. I'm also going to try the image buffer approach, it is, drawing in
> a buffer as a member variable and write the buffer's content to the
> Cairo context in the expose event.
>
> Still I don't understand why can't get a context and store it in a
> member variable.
>
> Regards,
> Diego A. Fons.
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