Re: [Scid-users] Mouse Wheel handling without focus stealing

[Cristian S. <cri...@gm...>]

> Unfortunately there are still some small issues, for example:
> - Without the "break" in ttk_bindMouseWheel the message continues to be
> propagated (add a line "return" in gamelist.tcl:823 to try what I mean)
>
With disabled glist.ybar_, mouse wheel is handled by Treeview class but
in current master this does not happen because class bindtags are disabled
by the breaks in ttk_bindMouseWheel.
The patch removes these breaks so that ttk_bindMouseWheel could be (re)used
as the native Tk one.

Initially I relied only on class binding, but the Treeview scrolling does
not work as you would expect and during testing I did not notice that. Only
at the end I re-enabled glist.ybar_ to not break things.


> - Mousewheel no longer works over the board when browsing a game
>
What do you mean? This should not happen, but I may have overlooked an
obvious scenario.



> I think the approach is the right one, but I think we should have a single
> function that is called from the windows that want to handle the mousewheel
> (autoscrollframe, main, gamelist, gbrowser; perhaps ttk_bindMouseWheel can
> be
> adapted), and within that function deal with the particular case where the
> mouse is positioned in another window (creating another event directed to
> the
> right window).
>

I've played around with all the tips I could get my hands on and I found
this approach to be the simplest to reason about. In the beginning I even
dismissed it for adding code that should be in Tcl/Tk in the first place.
The single function approach (for example TIP 171
http://www.tcl.tk/cgi-bin/tct/tip/171.html which was my first choice) has
the problem that it adds a scroll to any canvas even if you don't want
that. The obvious problem is when you scroll the game and the board canvas
scrolls, or in FICS, you scroll over the clock and the clock canvas scrolls.
So instead of adding scroll to every canvas and then removing the wrong
ones, one by one, I prefer to know exactly what bindings there are. With
this approach, I don't add any more bindings then I disable so the net
result is zero. The only binding that I added was to glist.ybar_ since
without it the Treeview scroll was not enough.

Two ideas:
- ttk_bindMouseWheel (preferable ttk::bindMouseWheel
 for transparency) could make use of a "break" optional argument that
defaults to no.
- If you know about other classes used in scid that fire under MouseWheel,
those should also be disabled

Cristian