[Gambas-user] gb.desktop.x11 LargeDesktop support

[Benoit Minisini]

Le 25/10/2022 à 23:38, Bruce Steers a écrit :
> So my recent discovery was this...
> 
> using gb.desktop.x11 there are Desktop/Workspace switching features.
> I found this info... @ 
> https://specifications.freedesktop.org/wm-spec/1.3/ar01s02.html 
> <https://specifications.freedesktop.org/wm-spec/1.3/ar01s02.html>
> 
> 
>       Large Desktops
> 
> The window manager may offer to arrange the managed windows on a desktop 
> that is larger than the root window. The screen functions as a viewport 
> on this large desktop. Different policies regarding the positioning of 
> the viewport on the desktop can be implemented: The window manager may 
> only allow the viewport position to change in increments of the screen 
> size (paging) or it may allow arbitrary positions (scrolling).
> 
> To fulfill the ICCCM principle that clients should behave the same 
> regardless whether a window manager is running or not, window managers 
> which implement large desktops must interpret all client-provided 
> geometries with respect to the current viewport.
> 
> 
>         Implementation note
> 
> There are two options for implementing a large desktop: The first is to 
> keep the managed windows (or, if reparenting, their frames) as children 
> of the root window. Moving the viewport is achieved by moving all 
> managed windows in the opposite direction.
> 
> The second alternative is to reparent all managed windows to a dedicated 
> large window (somewhat inappropriately called a 'virtual root'). Moving 
> the viewport is then achieved by moving the virtual root in the opposite 
> direction.
> 
> Both alternatives are completely ICCCM compliant, although the second 
> one may be somewhat problematic for clients trying to figure out the 
> window manager decorations around their toplevel windows and for clients 
> trying to draw background images on the root window.
> 
> So from that we see there are 2 ways of implementing the desktops, one 
> involves multiple viewports and one is one large screen.
> 
> It seems gb.desktop.x11 is coded to handle the multiple desktops method 
> but not the single big screen type :(
> 
> I'm almost there with implementing this (see attached project)
> 
> the project contains a folder called X11LargeDesktop containing files 
> that add the following to gb.desktop.x11
> 
> X11.DesktopCount and X11.CurrentDesktop now works for large desktops.
> 
> DesktopWindow.Desktop now also works for large desktops.
> 
> X11.IsLargeDesktop True if large desktop false if multiple viewports.
> 
> X11.ViewPorts returns a list of the viewport positions if using large 
> desktop taking Orientation into account. Still todo: handle start 
> corners, currently assumes TopLeft.
> 
> X11.Supported As String[], returns a list of the supported wm commands 
> (from hint _NET_SUPPORTED)
> 
> X11.GetDesktopNames(DefaultName as String="Workspace") , get's the 
> desktop names or makes them up if not found.
> 
> 
>  From what i have read the hint _NET_DESKTOP_LAYOUT is the key, a single 
> large desktop will have this set but multiple desktops will not so i 
> have used that as the check criteria. I also seems my MATE is the only 
> desktop that uses the large screen method.
> 
> Also i'm handling using multiple rows/columns as defined at 
> https://specifications.freedesktop.org/wm-spec/1.3/ar01s03.html 
> <https://specifications.freedesktop.org/wm-spec/1.3/ar01s03.html> but I 
> cannot test it as my desktop does not do it.
> 
> (have not handled start corners yet)
> 
> 
> tested on LinuxMint, desktops  MATE/Plasma/Cinnamon/Gnome
> 
> other than my Mint/MATE the class uses the original X11 routines that we 
> know works for multiple viewport desktops.
> 
> Dunno if you want to rip this code Ben (or laugh at my awful 
> implementation and do it properly yourself ;) lol )  gb.desktop.x11 is 
> lacking this "other method" so here's a little work on the matter :)
> 
> Wishing well
> 
> BruceS
> 

I will look at it.

-- 
Benoît Minisini.