Re: grid and graph questiones

["Dr. Roland Bock" <box2OO6 eudoxos de>]

Hello Arne,

> A few questions:
>
> I used the grid and the cross-simple.
> when I zoom in the box, the cross simple will disappear,
> I will never come back, even if I zoom out.
> It seems the grid paints over the cross, because the zero of the cross 
> stays still there.
> Do you have an Idea what can be the reason?

Graphs are drawn in the reverse order in which they were added. Thus, if 
you add the grid first and then the cross, it could well be that the 
cross is hidden behind the grid.

It seems strange, though, that you can see it in the beginning and after 
some zooming, it is gone and won't reappear. Haven't seen that, yet. If 
you can reproduce it with a short sample, I'd like to look into it.

> Do you think it is easily possible to add a new graph function?
> I want to have a graph with non-interpolated lines, so that I can see 
> the steps.
> As I saw, the lines at the moment are interpolated linear, can you tell 
> me where in the code it is done? Perhaps I can add the step-graph by 
> myself.

You have two options at least:

a) Modify your data slightly to represent the steps with the exisiting 
linear interpolation.

b) As you suggested yourself, you could create a new graph. This should 
be fairly easy to do. The currently available graphs are in the gtk 
folder and named like the graph type, e.g. gtkdatabox_lines.[ch] or 
gtkdatabox_points.[ch].

> Is it possible to change the grid-lines?
> I want to use a master grid, like the grid now, and a slave grid only 
> with dots.

You can see two grids in action in the example/grid.

Changing the line style of one of the grids should be possible by 
modifying the GC (gtk_databox_graph_get_gc/gtk_databox_graph_set_gc).

> gtkdatabox is great, and much faster then gtk-extra, but it could have 

:-)

> some more features :-)

Well, please go ahead, name them and help to implement them. The library 
depends on input from its users :-)

New features should impair neither performance nor ease of use and they 
should be of general usefulness. Within these limits, there are 
certainly lots of possible extensions.


Regards,

Roland