I have returned to the colourful world of UI (still refusing to say UX :) ) development.

The new pretty thing that is taking away my time is the activity switcher which got a rather big revamp for the next release of Plasma.

{% youtube nVUTww3oMhA %}

Apart from the new UI, it got a few usability improvements, namely full keyboard navigation. You are able to filter, navigate and switch activities without touching your mouse.

Meta+Tab activity switching

Unfortunately, not all is great - the Meta+Tab shortcuts for switching activities are not going to be enabled for the first release, they will have to wait for the one after.

What will that look like?

As you can see in the screen-cast, the Meta+Tab will (unlike old Plasma) have a visual feedback - it will show the switcher until you release the Meta key. Similarly to how Alt+Tab for window switching works.

Per activity global shortcuts

The second thing that will need to wait is the port of the global shortcuts plugin by Makis Marimpis. I expect it to be present in the same release as Meta+Tab.

Foreword

Since we lost the King Nepomuk at the battle on the now red desktop fields near the Semantic River, the common people lost the ability to tie things to their activities.

Stories and hymns of how King Nepomuk got to the throne by learning the sacred skill of tying things to one another with differently coloured strings and with labels attached to them, will remain in our heads and hearts for years to come.

The most famous and loved will always be the balad of the Active lands of Plasma where the society became so enlightened they managed to expel the Royal Society for Putting Things on top of other things.

What the future (KF5) brings?

Ok, stopping with the story now.

KActvities are back in the world of semantic linking, this time without Nepomuk, and without any unnecessary performance overhead. The new service implements all the features Nepomuk provided for activities, but also goes a bit further than that.

Everything is exposed to the developers via the ResourceModel available via the org.kde.kactivities QML import.

With the new system, we are finally able to implement one of the most requested features - to be able to define some Kickoff/Homerun/Lancelot/whatever favourites to be tied to a specific activity while leaving some to be global as they are now.

A small task for a volunteer

If someone is willing to port the Dolphin plugin and the Activities KIO to the new system (for KDE SC 4.13), please send me an e-mail.

Namely, the new activities service (although based on Qt5/KF5) can and should serve as a drop-in replacement in the future 4.x releases (if the distributions decide to ship it, I’m not going to force the issue).

In order to restore the missing features that depended on nepomuk, the two components from above need to be implemented to work with the new service.

My current focus is on KF5 and Plasma Next, and I’m not going to be able to implement those any time soon.

So, if you think you’re up to the task, and would like to be able again to link stuff to activities in 4.x, ping me.

I have been honoured by the voters for the upcoming Meeting C++ conference. My submission got the most votes for the popular track without me whipping the votes*.

I have to say that it will be awesome to have the opportunity (and challenge) to speak at the same location where the great Scott Meyers will be the keynote speaker.

If you are close to Berlin in December and love C++, I guess there is no better place to be.

(*) I’ve been waiting to use this phrase since I first saw the “In the loop” and “House of Cards” :)

There was a post recently about running a static code analysis tool on Qt 5 with some rather cute results. The main purpose of the post is to advertise the tool used, but it does make a nice point of how careless we can be when writing the code.

Since KDE is a Free/Open project, we don’t usually have the necessary finances in order to be able to use the tools like the one linked above. Fortunately, not all is grim. The great people at Clang, apart from making one of the best C++ compilers, provide us with a few tools as well.

I’ve written about clang-format some time ago. Now, it is the time for another, a bit younger project - Clang Analyzer.

What is it?

The Clang Static Analyzer is a source code analysis tool that finds bugs in C, C++, and Objective-C programs. The analyzer is 100% open source and is part of the Clang project. Like the rest of Clang, the analyzer is implemented as a C++ library that can be used by other tools and applications. ~ from the project’s website

It tries to analyze the different execution paths of your code and try to detect whether some of them can lead to problems.

As an example, I’ve used it on KActivities. And I got a false-positive, but a very reasonable false-positive. Namely, one variable was not initialized when declared, and as far as the analyzer is concerned, it might have been left uninitialized till its insertion into sqlite.

In reality, it was initialized in a range-for loop which is guaranteed to have at least one iteration, which the analyzer could not have known. It took me more than a minute to explain to myself that the variable can not be uninitialized, so I can not blame the the static analysis for the false alarm.

How to use it?

At the moment, it does not have a very sophisticated mechanism of execution. It follows the usual pattern of wrapping the compiler commands (similar to icecream, colorgcc etc.).

You need to set your build to use the wrapper instead of the actual compiler.

Lets say that you have installed Clang to /usr/local and copied the llvm/tools/clang/tools/ directory to /usr/local/share/clang/ (the analyzer is not installed by default, so you need to copy it manually).

You can create a separate build directory (in my case /opt/kf5/build-analyzer/path/to/your/project) and invoke cmake from there like this:

cmake /path/to/your/project's/sources \
    ...options you normally pass to cmake ... \
    -DCMAKE_CXX_COMPILER=/usr/local/share/clang/tools/scan-build/c++-analyzer

After cmake finishes its magic, run the analyzer:

/usr/local/share/clang/tools/scan-build/scan-build \
    --use-analyzer=/usr/local/bin/clang++ make

It will compile your project and analyze it at the same time. It will take much more time than an ordinary compilation run, but that is to be expected because of all the additional work it does.

To see the results, you need to run the scan-view command which will start a small web-server and point your web browser to it. You’ll be able to browse the detected issues from there. It nicely displays the sequence points that lead to the detected problem.