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Combined KDE Title bars and menu bars - an implementation

Tuesday 25th August 2009

There has a been a few suggestions (and one of the highest ratest KDE brainstorm ideas) of merging the window decorations and the window title into a single bar. The current system that we are used to has a lot of unnecessary white space particularly vertical pixels which is a problem for tiny factor notebooks.

Below is a mockup from someone on the KDE forums

The proplem that exists is that the window decorations are drawn by the window manager KWin, wheras the menu bar is drawn by the owning application.

The proposed solution:

• Application exports the menu to kwin via DBUS
• Kwin renders the menu
• When the user clicks a menu, it sends a DBUS call back to the application
• The application then renders the drop down menu in the appropriate position on screen

This is clearly very messy, and sucks. A lot.

The alternative

There is another approach, which I've not seen anyone else discuss:

• The application draws both the menu and window decorations itself
• Application forwards movement of title to window manager

To me this seems a much cleaner solution, the idea of window managers needing to draw the coloured bar at the top of an application seems to be a very legacy decision and there doesn't seem to be any reason for it. It's a bit controversial, but I think it's a step in a good direction. It even allows the user to use a different window manager and keep the combined window titles.

My code

Anyway, I drafted up up a bodge to one of the KDE tutorial windows to show the idea in action. It allows people to see if combined menu and toolbars is good from a usability point of view and to try to overcome some of the UI problems it poses (such as where to now put the window title!) however the idea gets implemented in the future, if people decide it is a good idea.

My implementation has a few issues:

• It looks very fugly, though there's no reason why it wouldn't look identical to the existing oxygen theme if I spent some time on it and shared the same rendering code
• There are no window frames.. because I forgot about them. This is actually more of an issue.
• I can't decide where to put the window title, this is more of an issue with the concept of combining the two bars rather than an implementation issue.
• There is also talk of people wanting tabs combined with the window title..we can't put all 3 there!

A real version of this technique would involve changing KMainWindow so all applications inherit this ability without further code changes.

It also would only take a minor modification and we can copy a feature I've seen whilst running spotify under Wine of allowing the user to move a window by dragging from any whitespace in the toolbar.

Without further ado. Here is a screenshot, and a link to the source. No modifications to KWin are needed!

Source tarball

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