Re: logarithmic axis/grids

[Fabian Foerg <fabian foerg gmx de>]

Laurent Perez wrote:
> Hello ;
>
> According to Gtk documentation, GtkRuler is considered too specialized
> and will eventually be removed from Gtk. NxpRuler seems to be what
> GtkDatabox lacks to be the perfect widget we need.
>
> I've created 2 packages from Fabian's cournol [1] that can be found here
> [2] : 
> - NxpRuler ; 
> - modified version of GtkDatabox to use NxpRuler.
>
> I wrote a small example (ex-1.c in examples dir) but unfortunately I
> didn't succeed in : 
> - making changes on the ruler to change accordingly the graph ; 
> - using ruler log mode. 
>
> As far as I can see, cournol didn't use the modified version of
> GtkDatabox. So, Fabian, am I doing something wrong ?
>
> Thanks.
>
>
> Laurent.
>
>
>
> References :
> ¯¯¯¯¯¯¯¯¯¯¯¯
> [1] http://cournol.k-2007.de
> [2] http://laurent.perez2.free.fr/download/gtk
> _______________________________________________
> gtkdatabox-list mailing list
> gtkdatabox-list gnome org
> http://mail.gnome.org/mailman/listinfo/gtkdatabox-list


Cournol uses the modified version of gtkdatabox, i. e. the rulers from 
counrol are nxprulers not gtk rulers. The modification patch is under 
patches/gtkdatabox.diff in the cournol source archive.
Cournol does not use logarithmic scales, though. You can easily replace 
the linear scale with a logarithmic one by adding the line 
"nxp_ruler_set_mode(NXP_RULER(ruler), NXP_RULER_LOG);" after the 
initialization of "ruler". Your ex-1.c looks like lib/nxpruler/test.c 
from the gnumexp sources. So actually it should work.

> I wrote a small example (ex-1.c in examples dir) but unfortunately I
> didn't succeed in :
> - making changes on the ruler to change accordingly the graph ;

What do you mean? In ex-1.c no graph, only a drawing area is drawn.
Here, the scales change appropriately when you resize the window.
For changing the range of the scale, you would write, for example: 
"nxp_ruler_adjustment_set_range(nxp_ruler_get_adjustment(NXP_RULER(vruler)), 
0, 10);". This changes the scale range from 0 to 10.

While testing the logarithmic scale, I encountered a problem.
---snip---
nxp_ruler_set_mode(NXP_RULER(vruler), NXP_RULER_LOG);
nxp_ruler_adjustment_set_range(nxp_ruler_get_adjustment(NXP_RULER(vruler)), 
x, y);
---snip---

This code sets a scale range from 10^x to 10^y for vruler.
Actually, I had expected a scale from x to y which gets logarithmically 
"denser" (or "wider", respectively) from one side to the other side.
Maybe I totally misunderstood the concept.
Gustavo, any ideas?

Greets,
Fabian