Re: [gtk-list] Re: Scrollable Widgets (Re: GtkText & scrollbars)

[Steve Hosgood <iisteve iiweeble swan ac uk>]

> Owen Taylor wrote:
> > Tim Janik <timj@gtk.org> writes:
> > > On 12 Oct 1998, Owen Taylor wrote:
> > > > 
> > > > What really should be done (TM) - is that scrollbars should be _removed_ 
> > > > from all widgets that have them currently. And then there should
> > > > be a generic interface added so that you could drop a
> > > > Viewport, a Text widget, a CList, a CTree, a GtkLayout, a
> > > > GnomeCanvas... etc. inside a GtkScrolledWindow and
> > > > it would work.
> 

This certainly sounds like a Good Idea. However, if you try it, see if you can make
allowance for more than just a pure GtkScrolledWindow in its current form.

Here's what happened to me recently. I've been writing a display and edit program
for geographical information gleaned from GPS receivers. ( The eventual hope is to
create something like 'Autoroute', but with all the data on roads derived from
people sending in GPS track files. )

Anyway - the problem came in the display. The world has not got a finite surface!
But GtkScrolledWindow does its scrolling by means of scroll bars - and this isn't
a very good way of scrolling the surface of a sphere. You don't really want to be
able only to scroll to +/- 180 degrees longitude with a scroll bar. If you scroll
west (or east) for long enough you might like eventually to get back to where you
started.

What I did to avoid it was to write my own self-scrolling map display with a set
of four buttons in one corner which let you move east/west/north/south. This also
got me around the 32K pixel problem.

P.S. My GPS program isn't complete enough for exhibition yet, but I will release it
when it is mature enough.

--

Steve                                       | Steve's law of House Rewiring:
S.Hosgood@swansea.ac.uk                     | "No matter how many power sockets
Phone: +44 1792 297292 + ask for Steve      |  you fit in a room, you will run
Fax:   +44 1792 295811                      |  out within the first week of use
--------------------------------------------+  even if you took Steve's law of
http://iiit.swan.ac.uk/~iisteve/steve.html  |  House Rewiring into account"