Re: exposing cairo context from gnuplot

[Richard H. <ric...@st...>]

On Tue, 2009-09-08 at 09:27 -0700, Ethan Merritt wrote:
> On Tuesday 08 September 2009 01:44:25 Richard Henwood wrote:
> > On Mon, 2009-09-07 at 17:49 -0400, Allin Cottrell wrote:
> > > 
> > > I think what Richard was asking is whether the "cairo drawing
> > > context" struct, or "cairo_t", that is used internally by gnuplot
> > > could somehow be exposed programmatically.  But I don't see how
> > > this could be done -- seems to me it would require building
> > > gnuplot as a library, not a stand-alone executable.
> > > 
> > 
> > This is indeed what I am curious about. As you comment: if the 'cairo
> > drawing context' was exposed, it would then allow gnuplot to behave as a
> > library. i.e. if one was writing a cairo widget for a (typically GTK)
> > application, one may create a context (cairo_t), pass it to gnuplot
> > (along with some commands to plot a graph on it), and then return it to
> > the application for display.
> 
> The two halves of your statement do not quite match up.
> While I understand wanting to pass gnuplot a context, e.g. a widget in
> an external application, I don't see what that has to do with making
> gnuplot into a library.  This mode of operation is already supported by the
> qt, tkcanvas, and x11 terminal drivers.  You initialize the context,
> invoke gnuplot, and tell it to draw into your existing context rather 
> than creating a new one.  Of course the details are different in each case.
> 

Ah! This is good news. So presumably if a 'cairo' terminal driver
existed, this would provide me a way to get nice gnuplot plots into my
GTK/cairo application?

> > In the first instance I thought I would raise this idea for discussion.
> > If it is technically feasible - and within the gnuplot mission - I think
> > there is an excellent opportunity to both have a extensive, publication
> > quality plotting library available to gtk/cairo application developers -
> > and increase usage of gnuplot.
> 
> I personally think that plotting libraries, as opposed to plotting programs,
> are not the way to go.  That's just my personal opinion, but it is based
> on years of programming experience using both approaches.
>  

I don't think I have sufficient experience to comment - and defer to
your judgement on this. I will have a poke around with the existing
qt/tkcanvas/x11 terminals and see how I get on with them.

cheers,
Richard
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