On Thursday 25 October 2012 13:29:13 Ryan C. Gordon wrote: > > Also in the case of KDE Plasma Workspaces the window manager is not at all > > responsible for handling the resolution. This is done by a daemon called > > krandr. I will not add code to change the resolution as that is nicely > > handled by krandr. So we would need to announce the support only if the > > daemon is present - this is something we would most likely not be able to > > guarantee correctly as in session start KWin should be started before > > krandr and it's possible that KWin is run outside a KDE Plasma session. > > To be clear, I don't think _any_ window manager currently has code to > change resolutions (indeed, the core of the problem is that the app is > doing that itself without any coordination with the system). I think > it's great that KDE has a clear chain of responsibility for who is > allowed to interact with XRandR, which means this can be cleaner for you > than it might be for, say, Gnome. > > How I would envision this working is something like this (I have no > experience with KDE source code, so this might be pure fantasy on my > part)... > > - krandr sends a notification to KWin once it starts up, and then KWin > can begin advertising the appropriate atoms. If a fullscreen app wants > to start up in the very first seconds of the KDE session: too bad, but > if we're being really fancy, KWin could stall that app until krandr is > ready. > - If you run KWin outside of a Plasma session--and therefore never have > krandr--KWin never advertises the atoms and never supports the > extension. That's what you get for not running KDE the way God intended. :) > - An app requests the _NET_WM_STATE_FULLSCREEN_EXCLUSIVE atom, KWin asks > krandr to change resolutions, and does NOT resize any of the windows or > move around desktop icons (etc) when it gets the resolution change event. > It makes the appropriate window the top of the Z-order, etc. Other apps > have no idea anything has changed for the most part. > - When the window loses focus (user alt-tabbed out of the game, window > is legitimately being destroyed, etc), repeat this process, telling > krandr to return to the original resolution. > > I'm ignoring some of the minutiae here, but that's the basic gist of it. > Does this sound like a reasonable approach for KWin? Honestly? No. That would be way too invasive change to the handling of KWin internals. E.g. we currently do not support changing the atom what KWin supports also to not handle the resolution change is not at all trivial. If someone would propose a patch to do that I would probably not accept it due to the many possibilities that this could go wrong. I don't like fragile code. I think on this thread a good approach has been highlighted: upscaling in the compositor and not changing the resolution. That would not be invasive in KWin. Cheers Martin
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