Tag: Akademy KWin

Those who attended my talk about KWin Mobile at Akademy could see the new KWin effect which demonstrated that it is possible to embed web content in a KWin effect. Unfortunately nobody could see the highlight of the effect as Germany scored too early and too late. If somebody scored a goal a nice animation would have been shown. I just modified the effect to show the animation on startup to be able to record it. As always: sorry for the bad quality – recordmydesktop does not like me.

Direct download as ogv

And yes the effect is called "Kicker", as it connects to kicker.de to get the current score and in remembrance to a well known panel I kept the name. The effect is quite simple and is just something like 200 lines of code and it took me only one hour (first half of match Spain vs Chile plus the half time – yes I was confident that Germany will have a match during my talk) to implement the parsing of the current score and displaying it on the screen.

Each half a minute the effect connects to the remote site and downloads the html file. Using QtWebKit and some small reverse engineering it extracts the names of the two playing teams and the current score. These strings are combined and put into an "EffectFrame" – our high level API for displaying Plasma styled textures on the screen – and shown on each screen.

The effect also caches the current score and compares it with the previous one. If it changed we know that someone scored a goal and the animation is triggered. This animation (as seen above) uses another EffectFrame, but this time an unstyled. The animation will stop after seven seconds. In that duration the texture’s opacity value is constantly increasing and decreasing, so that you have a flash event. We have a high level API for that as well: KWin::TimeLine which wrapps QTimeLine in an API tainted for the usage in KWin effects.

The code is of course useless for KWin trunk as it is a really special feature and I don’t like the QtWebKit dependency in the effect library. Nevertheless I will import the code into our test directory as it is a nice example on how to use the EffectFrame and really showing how flexible our effect library is.

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This weekend I prepared my slides for next weeks talk at Akademy about the mobile edition of KWin. I will talk about the reasons why we need a KWin mobile edition and why that will also benefit the desktop edition of KWin. For those who are not that familiar with KWin’s Compositing stack I will explain how the system works and where and how we can work on the OpenGL ES port. So that requires to illustrate the differences between the various OpenGL versions and what we have to do to get KWin’s codebase compiling on Maemo. As I have not yet started to implement the port (I think 4.5 is currently more important) I will also provide a roadmap on when we will see the pieces hitting trunk.

As my talk has a very special time slot I prepared a KWin effect on Friday evening for the talk. It’s a small but useful effect for the purpose and took me only about one hour to implement it and a nice effect to illustrate KWin’s flexibility, which is of course also part of the talk. Now I don’t want to spoil it, but I think it’s a nice and elegant solution to the problem that my talk collides with the second half of the quarterfinal Germany vs Argentina or Mexico. So please come to my talk and don’t stay in front of the TVs 🙂 I really love football and I can’t remember that I ever missed a German match at a World Cup. Given the way Germany played today, it will be really hard to miss the game. Who btw planned Akademy during World Cup?

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