The Universe is full of the hydrogen and one of its emission lines that is very important in astronomy is caused by the hyper-fine interaction. This electromagnetic radiation has the frequency of ca. 1420.4MH which corresponds to the vacuum wavelength of ca. 21cm.

Observations performed at this wavelength reveal many structures in the Universe. The following plot shows the results of such observations in the Milky Way...

• Wrapping up 2020 and looking forward to 2021

  As 2020 comes to a close, there’s several things ongoing around KDE Itinerary which a year ago I would have considered out of reach, or simply didn’t have on the radar yet at all. The common theme in all of those is collaboration with other communities and organizations. And I’m looking forward to more of this in 2021!

• December updates and a Christmas goodie for cable geeks

  ...my Plasma5 ‘ktown’ first got adopted as Slackware ‘vtown’ in testing and a bit later replaced the old KDE4 in the core distro. Lots of package recompilations and upgrades to work with the newer stuff in Slackware.

  [...]

  Despite that stress I have been enjoying myself still, just not in the spotlights. The semi-sudden switch in Slackware from KDE4 to Plasma5 and refreshing its XFCE Desktop had some consequences for my liveslak project. It took some time to work out a new optimal package set for the small XFCE image, and in particular the DAW Live image which is based on a bare Plasma5 Desktop needed attention to make it tick again.

• Blog housekeeping and stuff

  I had planned to write different blog post but this housekeeping took most of the time for me, so I will finish post tomorrow.

  On separate topic, I realize my blog has been dormant for a year now. Last blog post I made was Plasma Mobile as a daily driver about when I was stuck in Europe with no working phones except PinePhone. While this blog was mostly dormant, I had been writing various posts and contributing to posts on Plasma Mobile blog.

I want KDE applications to offer thumbnails for as many file types as possible, so over the years I’ve written a bunch of thumbnailers in kio-extras, such as for AppImages, Open Document (odt, ods, odp, …) files, various ebooks formats (epub, fiction book), Microsoft Office XML documents, and other files conforming to the “Open Packaging Convention”. Thankfully, modern document formats are often just ZIP archives (that can easily be handled using our KArchive framework) which already contain a thumbnail generated by the authoring application.

Furthermore, I even improved the Windows EXE and ICO thumbnailer to choose the prettiest icon available and even added support for friggin’ 16-bit executables from Windows 3.1. Qt already comes with support for reading ICO and CUR (Cursor) files but there’s no support for animated cursors (ANI). Naturally, I sat down and started writing a thumbnailer for that. A short while into reading the file format specification, I realized I might as well write a proper KImageFormats plugin, so that any Qt application, like Kolourpaint and Gwenview, can present those files. Gwenview would even play them like a GIF animation!

[...]

A few days ago Nate was approached about a new “platform profiles” ACPI API that will be added to the Linux kernel. It will allow to apply certain power management presets, such as “balanced”, “quiet”, “performance” without having to worry about changing specific details, like setting CPU frequency explicitly on the software side. Knowing that I’ve wanted a setting like this forever, Nate told me about this, and on Christmas Eve after returning from a smaller-than-usual family dinner I fired up a Linux kernel build and wrote a KAuth helper for manipulating those new sysfs files.

[...]

I also added a PowerDevil action which can automatically change the profile when you plug in/out your power supply or the battery is running low. Finally, I also added a DBus interface for enumerating and switching profiles that can then be used for some sort of UI in battery monitor to change between profiles anytime. I actually haven’t managed to get it working on my ThinkPad just yet but it looked simple enough to write that plug-in blindly.

One of the important parts of getting-started in an project is setting up a developer environment (if you want to do code contributions; other kinds of contributions need different setup). Calamares has a thing called deploycala.py which mangles the system it is run in (recommended only in VMs or live-ISO) while the KDE project has a wiki page on getting involved as a developer and a build tool that can do initial system setup and help with builds.

As a most-of-the-time-FreeBSD developer, I’m somewhat spoiled for a developer environment: a compiler (clang) is included, and installing package something also installs all the development tooling required for something. In other words: chasing development dependencies is pretty much trivial.

Many Linux distro’s support split dev-packages, and the names of those vary per-distro. My own deploycala.py script handles a half-dozen common variants. The kdesrc-build tool from KDE does something similar, with known-dependencies lists for Alpine, Arch, Debian, Fedora, Gentoo, Mageia and openSUSE (presumably “and derivatives”). So I decided to put this to the test by turning my recently-installed Plasma Mobile on Desktop into a development VM. Should be simple: the base is KDE neon User Edition, which is (kind of like) Ubuntu, which is (kind of like) Debian, so it ought to be straightforward.