View source for Plasma/20070207

== Meeting: Feb 21, 2007 ==

=== Summary ===

First thing, Aaron explained us what his idea of Plasma is and why he arrived there. Especially, he said that: ''«we need an amarok of the desktop so people go "oh. -that's- why"».''

For those still not familiar with this concept, he also explained that everything will be ''«a widget (or, as somehow caught on, a "plasmoid")... from the launcher buttons to full on widgets and mini-apps»''
Especially, the desktop won't be centered anymore on displaying the content of a folder. This will remain available though, everyone will still be able to do a full-screen plasmoid that shows the content of a certain folder. ;-)

After that, we started the discussion on what needs to be done. The first thing to do is to get all the essential components that still are in KDesktop been moved away. We are at a good point at this, because everything but the autostart stuff has already been moved into KRunner.

KRunner is a new application for KDE 4, created to replace some of the KDesktop functionality, that will manage the screensaver, that will show a task list when needed (like the windows' key combo Ctrl+Alt+Del), that will provide a run dialog and that will manage app startup notification.
KRunner will be a standalone app that will register global shortcuts and will show things on-demand.

The autostart stuff should probably be merged in ksmserver (it makes much more sense there), and be unique (right now there are ~/.kde/Autostart and ~/.kde/share/Autostart).

After having the old desktop killed, we will work on a replacement, and this has three separate needs: we should use a widget that supports background painting (the wallpaper), we should support zooming and the possibility to have containers, and we need to create efficient widgets (zoom aware, e.g.).

Using or not QGraphicsView is a major concern right now, but we concluded that probably the final decision on what to use has to be delayed to the next meeting, or, at most, to the end of march. We need to get in touch with the TT guys and see whether is possible to have a performant QGraphicsView for zooming in Qt 4.3 or not. In case the answer will be not, we will create a new class adapted for our needs, modifying the existing engine. It seems that we all agree on the fact that we'd love to use QGraphicsView, although it's a tricky decision to take right now. We decided to make use of it until the end of march, and then we'll see if performances still make possible to continue using it.

It will also be really nice to make QGraphicsView capable of embedding widgets. It shouldn't be a very difficult thing to implement, but actually there is still no support for that. :-(

We will probably also need to create our own set of high-performant widgets, to enable really fast zooming and animations. For example, the text can disappear while zooming, or we could not redraw the widget while the zoom factor remains under 0.75... or something like that.
Anyway, the widgets we will need should be:
* A label
* A button
* An svg viewer
* An html widget
* A lineedit/textedit

We still need to concretely define which optimisations can be done for _each_ widget, and then we will be able to actually write the code for them.

'''ADD:''' wirr just told me that lineedits, labels, and an HTML widget are already there in the QGV version of SuperKaramba. Have a look!

Then we talked about visualization and the engine, and we decided to make use of some of Zack's physical equations ([http://ktown.kde.org/~zrusin/examples/box2d.tar.bz2 1], [http://ktown.kde.org/~zrusin/examples/blobs.tar.bz2 2]) to make the animation the best (and less boring) possible. Aaron also stated that we're ok as long as we don't run the physics engine continuously, otherwise it tends to burn CPU cycles.

Aaron smacked his gavel on the desk at 20:54:45 CET, putting the word 'end' to the first plasma meeting. It lasted 1 hr 49 min and 53 secs.

Next meeting should be next week, same time. The topic will be (mainly):
* Engines update
* Scripting (Kross, QtScript, etc...)
* Plasmoids

=== Transcript ===

The transcript of the meeting is available [http://giannaros.org/kde/logs/Plasma_Meeting_2007-02-21.log here]; or, alternatively you can view it in HTML [http://giannaros.org/kde/logs/Plasma_Meeting_2007-02-21.log.html here].