Re: Other window managers

[Wolfgang Lux]

Christopher Armstrong wrote:

> Hi all
>
> I'm trying to write my own window manager for Etoile :-). GNUstep  
> integration is extremely important, but the way we are trying do  
> some things, vs the way that GNUstep operates is causing some  
> conflicts. I was hoping that I might get some advice on these issues.
>
> The first thing is using GNUstep with click-to-focus mode. We need  
> click to focus in Etoile for normal application windows because we  
> don't have title bars and allow the user to move windows when they  
> don't have the focus by just dragging them (none of this applies for  
> palettes or inspectors, which are traditionally decorated).

Just curious, how can you close or miniaturize normal windows if they  
don't have a title bar?

> I started to implement click-to-focus, but I've noticed that when  
> you transfer focus away from a non-GNUstep application and then back  
> to GNUstep, it ignores the first mouse click in the window after it  
> has been focused. I confirmed the behaviour with lwm too (note that  
> it can't be replicated in WindowMaker, as it explicitly disables  
> click-to-focus for GNUstep apps). I tracked this down to the window- 
> >ignore_take_focus flag. What problem does this flag solve, and can  
> it be removed?

This flag is just there to implement the OpenStep/Cocoa semantics  
without help of the window manager. In general windows are supposed to  
ignore the click by which they are focussed. While some window  
managers (e.g., WindowMaker) can be configured to not send the mouse  
click that focusses a window to that window, this obviously interacts  
badly with windows that are configured to process the first click into  
the window. In an environment where we do not have control over the  
window manager, there is hardly an alternative to this implementation.

> Secondly, I'm using EWMH window type hints to distinguish windows so  
> that I know how to decorate them. GNUstep really isn't  
> distinguishing normal windows from palette windows and inspectors  
> (at least not in Gorm). I know this is a difficult issue, and I  
> spent some time looking into how we can improve this. The Cocoa API  
> makes it difficult, because it only allows windows to configure how  
> they look and behave, not what they are or what they contain.

Why don't you use the _GNUSTEP_WM_ATTR property to determine the  
window style and level? The EWMH hints are essentially derived from  
this information and trying to recover this information from the EWMH  
hints seems a wasted effort.

> There are some things we could possibly use:
> * Style masks - these say whether a window has a close button, title  
> bar, minimise etc. we could say that windows without minimise flags  
> are "utility" windows.

> * -[NSWindow canBecomeMainWindow] and -[NSWindow  
> canBecomeKeyWindow]. Although panels by default cannot become main  
> windows, this doesn't always help. For example, Gorm allows its  
> palettes to become main.
> * -[NSWindow hideOnDeactivate] - as silly as it sounds, this one is  
> quite good because only normal windows don't hide on deactivate.
> * window levels - not entirely useful, because palettes and other  
> auxiliary windows don't need to use NSFloatingPanelWindowLevel.
> * The class type of the window (e.g. NSWindow, NSPanel, etc) -  
> probably not the best idea again, because a NSWindow subclass can  
> behave like a panel.
>
> I'm happy to prepare patches and test any proposed changes for these  
> things.

Before starting to patch -back (let alone -gui), first try to get  
things done with the _GNUSTEP_WM_ATTR property. If things are missing  
there then we might discuss how back could provide you that information.

Wolfgang