Re: [Ayatana-dev] Mentorship, Signal Propagation in Unity

[Sam Spilsbury <smspillaz@xxxxxxxxx>]

On Wed, Jan 5, 2011 at 12:22 PM, Josh Headapohl <joshhead@xxxxxxxxx> wrote:
> Yes! I needed to Ungrab the pointer. I get prelighting on the menu items
> now, without releasing the mouse button, but I still can't make selections.
> I think this is due partly to some code in QuickListView that checks whether
> mouse presses are inside the quick list area.
> How would I debug the Unity plugin? I found the following post (by you ;) )
> which says how to start Compiz with gdb, but it looks like I'm restricted to
> compiz core.
> http://forum.compiz.org/viewtopic.php?t=11246
> It might be that I just don't know how to use gdb very well! I've never used
> it with a project this complex before.

You should just be able to compile the unity plugin with debugging
symbols and then do breakpoints wherever (eg break
unityshell.cpp:linenumber or Launcher.cpp:linenumber) or on particular
functions. gdb will complain about how symbols aren't loaded yet, just
ignore this, it will auto-resolve them once they are dlopened.


> Thanks,
> Josh
>
>
> On Tue, Jan 4, 2011 at 10:21 PM, Sam Spilsbury <smspillaz@xxxxxxxxx> wrote:
>>
>> On Wed, Jan 5, 2011 at 11:05 AM, Josh Headapohl <joshhead@xxxxxxxxx>
>> wrote:
>> > Thanks Sam, for replying to my question and for pointing me in the right
>> > direction.
>> > I didn't see the inheritance structure before and everything makes a
>> > little
>> > more sense now.
>> > You are correct that the code that handles drag events does not look at
>> > which button is pressed. The LauncherIcon class does handle clicks and
>> > quicklist creation, while drag events are handled by the Launcher class.
>> > If
>> > I add a check in the Launcher class to consider which button is pressed,
>> > I
>> > can prevent the right mouse button from initiating drags.
>>
>> Cool, that's part one at least
>>
>> > Unfortunately, whether or not the launcher icon is dragged, if the mouse
>> > is
>> > initially depressed over a launcher icon, the quicklist ignores or
>> > doesn't
>> > receive events until the mouse is released.
>>
>> Yes, this is a bit of an annoying shortcoming (there is no way to
>> transfer the grab to another widget in nux). I think the way you will
>> need to do it is to XUngrabPointer (grep other bits of the code on how
>> to do this - I think the menus do it) and then then open the menu and
>> make sure it is "grabbed" currently.
>>
>>
>> Cheers,
>>
>> Sam
>>
>> > I guess that I am halfway to a functioning solution: The right mouse
>> > doesn't
>> > initiate launcher or icon drags, but I can't yet open the quicklist and
>> > make
>> > a selection in one click.
>> > Josh
>> >
>> >
>> > On Sun, Jan 2, 2011 at 8:12 PM, Sam Spilsbury <smspillaz@xxxxxxxxx>
>> > wrote:
>> >>
>> >> On Wed, Dec 29, 2010 at 12:27 PM, Josh Headapohl <joshhead@xxxxxxxxx>
>> >> wrote:
>> >> > Hello, I'm working on bug 688830 in Unity, which is about letting the
>> >> > user
>> >> > select a quicklist item with just one right click. Currently, you
>> >> > have
>> >> > to
>> >> > let go of the mouse button first or you will just start dragging the
>> >> > launcher icon. This behavior is annoying and the bug is tagged as
>> >> > bite-size
>> >> > so I decided to try to help fix it.
>> >> > Dieder Roche commented it could be "bitesize with good mentorship,"
>> >> > so I
>> >> > hope I can get a little assistance here in figuring out Unity's
>> >> > technical
>> >> > design. Okay, maybe more than the design. :) There's a lot to take
>> >> > in.
>> >> > I see that when there is an OnMouseDown signal emitted, a Launcher
>> >> > instance
>> >> > will handle it, and I can see where later in the chain of method
>> >> > calls,
>> >> > the
>> >> > quicklist menu item is created and shown in
>> >> > LauncherIcon::RecvMouseDown.
>> >> > What I haven't found yet is what sends the OnMouseDown signal in the
>> >> > first
>> >> > place.
>> >> > For example, in Launcher.cpp line 186,
>> >> > OnMouseDown.connect  (sigc::mem_fun (this,
>> >> > &Launcher::RecvMouseDown));
>> >> > What is OnMouseDown and where is it instantiated? Does it happen
>> >> > outside
>> >> > of
>> >> > Unity or am I just overlooking the place where it is created?
>> >> > I think if I could see a higher level source of input events (or do I
>> >> > mean
>> >> > lower?) , if would be easier to see what to do with them further down
>> >> > the
>> >> > line.
>> >>
>> >> The launcher class has a fairly long inheritance tree:
>> >>
>> >> InputArea -> View -> Launcher.
>> >>
>> >> InputArea is found in nux/Nux/InputArea.h/cpp . It handles raw events
>> >> (either from X11 or elsewhere) and makes the OnMouseDown etc signals
>> >> actually emit () once appropriate events are recieved.
>> >>
>> >> I have not looked at this particular code in detail, but I would
>> >> assume  that whatever LauncherIcon::OnMouseDown is connected to
>> >> handles the quicklist creation, button clicks and dragging - although
>> >> the code that does the dragging isn't checking which button is
>> >> actually pressed.
>> >>
>> >> Regards,
>> >>
>> >> Sam
>> >>
>> >> > Also, if it sounds like I'm approaching the whole problem the wrong
>> >> > way,
>> >> > feel free to point me in a new direction.
>> >> > Thanks,
>> >> > Josh
>> >> > https://bugs.launchpad.net/unity/+bug/688830
>> >> > _______________________________________________
>> >> > Mailing list: https://launchpad.net/~ayatana-dev
>> >> > Post to     : ayatana-dev@xxxxxxxxxxxxxxxxxxx
>> >> > Unsubscribe : https://launchpad.net/~ayatana-dev
>> >> > More help   : https://help.launchpad.net/ListHelp
>> >> >
>> >> >
>> >>
>> >>
>> >>
>> >> --
>> >> Sam Spilsbury
>> >
>> >
>>
>>
>>
>> --
>> Sam Spilsbury
>
>



-- 
Sam Spilsbury