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Re: USPosition vs. PPosition with Virtual viewports

Positioning "ordinary" application windows with respect to the screen glass rather than with respect to NET_WORKAREA breaks accessibility. This is something that really needs to be taken into account in these discussions. low-vision or mobility impaired users need to be able to rely on apps not impinging on the screen space used by onscreen magnification windows or onscreen keyboards, for instance. Allowing applications to do this without requiring them to participate in STRUTS or be type dock is a bad idea.
Maybe I am misreading some of this discussion, but it sounds to me as though some of the proposals here would not respect NET_WORKAREA, which is a 'bad thing' for accessibility. 

Best regards,

Bill


Carsten Haitzler (The Rasterman) wrote:


On Tue, 25 Oct 2005 09:48:18 -0500 Sasha Vasko <sasha aftercode net> babbled:


Carsten Haitzler (The Rasterman) wrote:


On Mon, 24 Oct 2005 22:07:19 +0200 Lubos Lunak <l lunak suse cz> babbled:



Dne čt 20. října 2005 03:29 Carsten Haitzler napsal(a):
On Wed, 19 Oct 2005 15:30:00 -0500 Sasha Vasko <sasha aftercode net> 
babbled:


There is a certain ambiguity in how geometry should be specified by
user, when Window Manager is supporting virtual viewports. This surfaced
as the result of GIMP abuse of USPosition flag which is outlined here

: http://bugzilla.gnome.org/show_bug.cgi?id=319099

Basically, for user to be able to place , say, a term window into
arbitrary viewport on the desktop, using just a command-line options -
geometry must be specified in relation to the desktop origin, there is
no other way around it. Therefore it is a duty of a Window Manager to
always treat USPosition in relation to a desktop origin.

On the other hand, as apps itself may not be aware of existence of
virtual viewports, and even if they do - its not possible to reliably
take it into consideration - PPosition must always be treated in
relation to the current viewport's origin.

Now this is not a transparent conclusion for anyone not involved with
window management to a certain depth, and therefore I suggest that this
should be clarified in specs under "Desktop/workspace model" subsection
of Implementation notes.

Anybody wants to comment on that ?

this is a tough one. most existing apps will see BOTH USPosition and
PPosition as ROOT window relative co-ordinate hints (out of practicality
and a loong history). changing this will mean breakage of at least some
apps. but this also makes using a virtual desktop + movable viewport a bit
of a nightmare,as i assume you are discovering.

basically a lot of wm's have ignored pposition in the past due to abuse by
apps (like netscape) and thus many aps have moved to abusing usposition
instead (though they do it better than netscape did). i know that
personally im gettigng to the point of encouraging users to use the lock
and override features of the wm to say "dont listen to the apps request for
position, size etc. use mine and ignore the app" as its geenralyl more
reliable :) thus in that scneario - the wm can choose to put the app where
it was last - relative to the virtual desktop co-ordinates, not the
viewport. :)
Does somebody think it wouldn't be completely naive to try to fix this USPosition/PPosition madness by adding some kind of I-do-it-properly 
property that both WMs and apps could set?

Qt also sets both US and P positions, because of the reasons listed above,
in order to work around broken old WMs and whatnot, and I've run already
into this a couple of times with KWin. Qt e.g. always places dialogs, and
although KWin has much better placement algorithm it's simply not of much
use because of US and P position set. I even tried to actually ignore those
flags in general for dialogs but that wasn't that good idea either :( . And
having the user to manually set setting for every app is not really a
solution.

agreed - for the aqverag user. power users when they get annoyed enough will
set it. :)

as for a new hint - i don't see this as a bad idea, but if we were to
propose such a hint - may i suggest we expand it a bit. we should:

1. provide another client window id (that should be mapped at the time) to
place RELATIVE to. (if not provided root is assumed). 2. a flag to indicate
if the position is screen relative (viewport relative) or desktop relative.
3. the ability to provide absoloute position offsets relative to the
top-left (or any other corner) but ALSO relative percentage offsets (as a
percentage of the relative window mentioned in 1. and its geometry at the
time the window is mapped.


Woa! Hold On! :)
That's a whole different aspect you are bringing in here.
As I see it we have two problems here now :
1) Let client apps know how Window Manager handles USPosition and PPosition
2) Possibly allow clients to request placement in relation to desktop
origin or another window ( which is what you are bringin up ).


well i added the "relative to another window" thing as an answer for "kwin does
better placement than the apps" - often apps want their dialog up - but
centered on their OWN "main" window for example. this can be used in many ways
- wm's can still ignore it too, but it gives the app power to say more :)


As to first problem I agree with Lubos, and here is what we could do :

_NET_PLACEMENT, ATOM[]/32

With possible atoms :
	_NET_PPOSITION
	_NET_USPOSITION
	_NET_USPOSITION_IS_DESKTOP_RELATIVE

For the second problem, I'd say it will be good enough if we'll allow
clients to request position in relation to its other windows, but not
root or viewport, as those should be dictated by window manager's own
policy. Even that is to much IMHO. and I think we need to start a second
thread for that discussion.


i definitely think the app NEEDs to be able to say if its requested position is
relative to the screen - the glass of the monitor, OR relative to a desktop.
often borderless windows like panels, and maybe temporary similar windows want
to position themselves relative to the SCREEN and possibly maintain that
positionr egardless where the virtual desktop viewport goes (ie sticky) - but
this is a different kind of sticky i guess. then there is requested position
but it may be relative to the overall massive desktop, or the currently visible
section. you could use sticky to try and indicate this - but i dones see any
harm in providing more information and allowing the wm to figure out what it
wants to do about it. :)


Sasha Vasko
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