Re: USPosition vs. PPosition with Virtual viewports

[Carsten Haitzler (The Rasterman) <raster rasterman com>]

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. :)

-- 
------------- Codito, ergo sum - "I code, therefore I am" --------------
The Rasterman (Carsten Haitzler)    raster rasterman com
裸好多
Tokyo, Japan (東京 日本)