Re: [PATCH] gitk: Add horizontal scrollbar to the diff view

From: Pekka Kaitaniemi <kaitanie@cc.helsinki.fi>
Date: Mar 6, 2008, 11:53 UTC
Message-ID: <20080306115347.GA11808@localdomain>
In-Reply-To: <18383.51154.695501.543720@cargo.ozlabs.ibm.com>

Hi,

On Thu, Mar 06, 2008 at 09:30:42PM +1100, Paul Mackerras wrote:

Show 11 quoted lines

> Junio C Hamano writes:
> 
> > An obvious solution is to show the scrollbar on-demand (i.e. when the
> > lines are overlong), but I do not talk Tcl/Tk and do not know if you can
> > do that easily.
> 
> I don't know of any extremely easy way to do it; it's certainly
> possible, but I think I would have to calculate the length of each
> line as it is put in, so as to get the maximum, and then have a
> handler for when the pane is resized, and pack and unpack the
> scrollbar as necessary.

I have spent some time today looking for examples on Tk scrollbar handling (I'm not really a Tcl/Tk guru) and I haven't found any really easy ways either.

> I think it's reasonable to have the scroll bar there always.  I think
> that pane could look better using the grid geometry manager (instead
> of pack), but that can be a separate patch.

I have modified the patch a bit to make the horizontal scrollbar a bit narrower so the impact on screen real estate should be smaller now.

The grid layout manager would probably be a bit better than pack for the left pane. At least most examples of "text and two scrollbars" case seem to be using it. Maybe I can try to prepare a patch that converts the diff pane from pack to grid layout.

An interesting side effect of Tk scrollbars is that by default the "elevator" size changes depending on the _visible_ content. So the horizontal scrollbar "elevator" changes as the user scrolls the view up and down.

Pekka