more on keyboard status

Michael Leupold has been working on a class for kdelibs that can report on keyboard modifier (and mouse button) states, the same thing that the keyboard status widget does internally. The class should appear in KDE 4.3, and this is quite nice since it gives us a platform-neutral way to do things like show when the caps lock is on in dialogs with passwords without reimplementing the code to do that over and over.

When Michael told me he was working on this in response to my last blog on the keyboard state widget I sat back and thought, "Why the heck am I dragging myself over the coals and modifying the 986 line of code literal-port-from-kicker thing in kdreview?! I should write a small DataEngine around Michael's class and then do the widget in JavaScript: it's just a collection of buttons, after all!"

So today while the P-man was off at a friend's place I scurried off to a coffee shop and sat down to work on the DataEngine part. Other than half an hour or so spent on some phone calls from friends and answering Plasma bug days questions, I was able to just sit and hack on it while sipping cappuccinos for two hours. The end result is a complete DataEngine plus Services in 198 lines of C++ that is (thanks to plamaengineexplorer) fully tested and working flawlessly.

Now any Plasma component in any language can easily interact with keyboard and mouse button states. You can even latch and lock modifier keys ...

... which means I'm now ready to play with some JavaScript. Using the service architecture I expect a dozen lines of code or so for the buttons to lock/unlock/latch/unlatch the corresponding keys and another dozen or three lines at most to create the buttons, hook them up to the engine and get the layout orientation right (e.g. vertical for Vertical constrained containments). When done this will be the first JavaScript plasmoid to ship by default in kdebase. I can't wait to see what limitations and bugs I run into in the process. ;)

I think I'll also take the opportunity to write a Techbase article on writing Plasmoids in JavaScript as I go, documenting what I do step by step.

With Michael's code, the whole thing should be less than 650 lines code, which is a 35% savings over the old keyboard kicker applet and done in a way that any KDE app or Plasmoid can take advantage of.

Huzzah.