gnucash, charts and interactivity

[Jean Bréfort]

Le dimanche 22 novembre 2009 à 16:42 -0500, Phil Longstaff a écrit :
> On November 22, 2009 03:45:23 pm Christian Stimming wrote:
> > 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.
> > 
> > > 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?
> > 
> > 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.
> 
> Probably a couple of things we could do:
> 
> 1) webkit does support image maps so that if you click on an image, you can 
> get information about the click.  This could be fed to the renderer.
> 
> 2) webkit now (after 1.1.14 or so?) supports embedded objects the same way 
> that gtkhtml did, so we can go back to the plot being an embedded object which 
> will react to its own clicks.
> 
> My preference is #2.
> 

#1 is easier to implement, imho, and webkit embedded objects support is
somewhat buggy at the moment.

Regards,
Jean