Re: Add function to make frame topmost?

[Lennart Borgman]

On Sat, May 1, 2010 at 12:32 AM, David De La Harpe Golden
<address@hidden> wrote:
> Stefan:
>>
>> I see, thanks.  I don't know if there's a word for such things
>> under X11 (I guess we should ask the freedesktop guys).
>
> Not affiliated with freedesktop as such, just familiar with specs:
>
> ITYM "Always on top" or "above other windows", or technically asking that
> _NET_WM_STATE include _NET_WM_STATE_ABOVE


Thanks.


> N.B. For "normal" windows (such as ordinary emacs frames), this is something
>  usually configured by the user via the window manager's menu, setting it
> within emacs for normal frames would not be something I would particularly
> want or need to do, though possible (*** below), and setting it for special
> framey things is not AFAIK a good idea (following):
>
> http://standards.freedesktop.org/wm-spec/wm-spec-latest.html#STACKINGORDER
>
> [lennart]
>> My use case for something like this is reminders that pops up at a
>> certain times.
>
> Note that X11 apps (or more usually the gui toolkit the app uses) specify
> the purpose of the window in higher-level terms _NET_WM_WINDOW_TYPE, like
> "this is a tooltip", "this is a notification" _NET_WM_WINDOW_TYPE_TOOLTIP,
> _NET_WM_WINDOW_TYPE_NOTIFICATION
> etc.


Then maybe the appropriate abstraction level would be this.

As I understand it the tooltip frame we have in Emacs today is quite
specialized and not easy to extend. I guess the purpose of making it
that way has been ease of the specialized use and low resource
consumption.

The problem is that it is not powerful enough for things like menus of
the type used by for company-mode or completion-ui (see EmacsWiki). So
I am trying to make a quick implementation on w32 of the necessary
frame parts (leaving the other parts to those doing the completion
user interfaces). What is needed is

1) a frame which is topmost.
2) looks like a tooltip frame
3) can show different things
4) can be hidden
5) can be shown without becoming active
6) never becomes the active window
7) looses it topmost property when switching to another app.
8) regains it when switching back
9) has to be recognized as such a frame by Emacs

I am not sure about this list, please comment. What about having a
function make-tooltip-type-frame?

As I understand what you write here much of this is easily available
on X with _NET_WM_WINDOW_TYPE_TOOLTIP. How about point 2 above? 4 and
5? 6? 7 and 8?

w32:
- For 4 and 5 on w32 I have just added the bug report
http://debbugs.gnu.org/cgi/bugreport.cgi?bug=6068
- And I just sent the function w32-set-frame-topmost here. This is
needed, of course.
- The w32 window style has to be modified for 2. (Just wrote this.)
- Same for 6.
- 7 and 8 are a bit more difficult (need to check WM_APPACTIVATE).
- 9 is not specific to w32. A bit has to be added to the frame struct.



> The window manager then places it in the appropriate stacking group, among
> other things:
>
> """
> This property SHOULD be used by the window manager in determining the
> decoration, stacking position and other behavior of the window.
> """
>
> The greater diversity in window management on X11 than windoze
> makes observing such things pretty important -  "this is a notification" may
> make a whole lot more sense to a tiling wm than "above plz k thx".
>
> Please note that abusing _NET_WM_STATE for attention purposes is
> specifically highlighted as a What Not To Do in the spec:
>
> """
> _NET_WM_STATE_ABOVE and _NET_WM_STATE_BELOW are mainly meant for user
> preferences and should not be used by applications e.g. for drawing
> attention to their dialogs (the Urgency hint should be used in that case,
> see the section called “Urgency”).'
> """


How does "Urgency" work? Is that appropriate for reminders? I would
prefer that to be a frame that pops up but does not get focus until
the user choosen it.


>
> ***
> One can certainly do this from within emacs as per the spec (note you
> do this for mapped windows by sending a client message to the root window).
>  Note however, that window managers may refuse an app's request to be always
> on top.
>
> (defun x-toggle-frame-always-on-top (&optional frame)
>    (x-send-client-message
>     frame 0 frame "_NET_WM_STATE" 32
>     ;; _NET_WM_STATE_REMOVE = 0
>     ;; _NET_WM_STATE_ADD = 1
>     ;; _NET_WM_STATE_TOGGLE = 2
>     '(2 "_NET_WM_STATE_ABOVE" 0 1)))


Does this work already?