gnucash, charts and interactivity

[Jean Bréfort]

Le dimanche 22 novembre 2009 à 21:45 +0100, Christian Stimming a écrit :
> Dear Jean,
> 
> thanks a lot for picking up this old issue, and thanks for your explanation.
> 
> Unfortunately, currently AFAIK none of the gnucash developers has recently 
> worked with that part of the code. This means we can happily apply concrete 
> patches, but I'm afraid currently there is nobody around who could use the 
> less concrete ideas for implementing this nice feature again. (Or is someone 
> interested? Just go ahead now...)
> 
> Am Sonntag, 22. November 2009 schrieb Jean Bréfort:
> > https://bugzilla.gnome.org/show_bug.cgi?id=359224
> > 
> > Btw, the renderer is not unreferenced in
> > create_graph_pixbuf, which introduces a memory leak, however, the
> > renderer will be needed later, so I think the appropriate way is to use
> > g_object_set_data:
> 
> Can you verify that http://svn.gnucash.org/trac/changeset/18437 implements 
> this correctly? It compiles fine here, but that is all I can check for now.

This is ok, but not useful for the old cairo and pixbuf renderers, you
might just call g_object_unref for them.

> > Now, the only way I can think of to get a callback for the graph, is to
> > use a server side html map
> 
> Thank you very much for the explanation. However, just to check I understood 
> this correctly: Are you saying goffice-0.7.16 implements "something like a 
> server side html map" for us? Do I understand correctly: We need to install a 
> callback which you've described in your message, and due to the new 
> gog_plot_view_get_data_at_point goffice will look up the series and index for 
> us? Then the only question remaining is how we could install the callback to 
> the pixbuf?

No, goffice does not implement a server side map, it just provides a way
to get which data are displayed at a given point.

> And of course gnucash itself must do something meaningful with the callback on 
> the series and data point. Currently I wouldn't know how to go on with this, 
> but I guess someone more clever than me should be able to integrate this in 
> our framework.
> 
> Regards,
> 
> Christian
> 
> 
> > ( http://www.w3.org/TR/html401/struct/objects.html#h-13.6.2 ). The URI
> > needs to include some way to know which pixbuf has been clicked, then
> > you just need a callback such as:
> > 
> > graph_clicked_cb (GdkPixbuf *pixbuf, int x, int y)
> > 
> > with x and y the coordinates given by the called URI as described in the
> > HTML specification. Of course, I might miss something, being not
> > familiar with gnucah code.
> > 
> > The callback should contain code such as (needs goffice-0.7.16 to build
> > and work):
> > 
> > GogRenderer *rend = g_object_get (pixbuf, "renderer");
> > GogView *view;
> > GogSeries *series = NULL;
> > unsigned index;
> > 
> > if (!rend)
> > 	return; /* can't do anything without the renderer */
> > g_object_get (G_OBJECT (graph->renderer), "view", &view, NULL);
> > /* get the appropriate child view */
> > view = gog_view_get_view_at_point (view, x, y, NULL, NULL);
> > if (!GOG_IS_PLOT_VIEW (view))
> > 	return /* clicked occur outside of any plot */
> > index = gog_plot_view_get_data_at_point (GOG_PLOT_VIEW (view), x, y,
> >  &series); if (index < 0)
> > 	return; /* nothing found at (x,y) */
> > /* now do want is needed knowing that you have the series and the index
> > of  the data inside the series */
> > ...
> > 
> > What is new in that code is gog_plot_view_get_data_at_point which did
> > not exist before 0.7.16.
> > 
> > Hope this helps, best regards,
> > Jean
> > 
> > 
> > _______________________________________________
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> > gnucash-devel at gnucash.org
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> > 
> 
>