When we first started creating themes, in 2015, GTK was on version 3.14, Ubuntu users were complaining about overlay scrollbars and Windows 10 was just released. At the time, the biggest themes were Numix, Arc and Ambiance variations. To edit a theme, it was enough to change a few colors, redefine some widgets in the CSS file and everything was ready. In fact, the first release of the Windows 10 theme was just a recolour of a Numix variant, flat unity.

In early 2016 GNOME 3.20 was released, and with it big changes. CSS was generated using SASS, the default Adwaita theme had an enormous ruleset and it broke backwards compatibility with earlier themes. At this time, we had generated quite a few themes and as we planned the porting process, we saw some themes would be left behind because porting them all was a big task for a small part-time team. It took 2 years to fully port all themes and the results were not pretty. Some early ports were acceptable but maintaining SASS-generated code was not easy, as that meant lots of redundant or unnecessary rules.

At this point, I started thinking of a way to reuse code and generate it using a custom built tool, as I didn't fully understood SASS at the moment. As I like fancy acronyms, I named that tool MTAC (Modular Theme Architecture and Compiler) and had a version for GTK 3.18 and another for 3.20. It worked by pasting together snippets of CSS, allowing for code reusability. However, there was no dynamic loading and code collections were full of symlinks for it to work.

TDK (Theme Development Kit) was supposed to replace MTAC by using SASS and removing the need for symlinks, but it never materialised.

Fast forward to mid-2018: most themes are 3.20+ compatible but with inconsistencies across all of them which are patchable but require too much time to correct across all themes. And with new themes planned and in development, things were about to get worse.

At this time, I was developing a theme using SCSS (B00merang Flat was supposed to, but didn't deliver). Work was complete around October and code separation was done by December. Code separation was the process of separating from the main file all code that was going to be reusable. 2019 was spent porting the themes to this new tool and making adjustments and enhancements along the way.

We have some pretty exciting plans for Azurra, which may one day result in you doing a unique theme completely from scratch and from a GUI application. Who knows!

Today, the B00merang Project releases a major piece in our build infrastructure. The Azurra framework, which has been improved for the past few months is going open-source under the GPL v3. It is available on Github for public usage.

For now, it's still in alpha, missing documentation and a definitive set of scripts (the current ones are hotfixes written on the spot), but we will continue to gradually improve it as time goes on.

Impovements to the upstream Azurra framework have been merged with our themes code. This brings:

• improved support for GTK-based desktop elements (xfce4-panel, mate-panel, gnome-flashback)
• Possibility to vectorize assets in the future (via Vrender)
• Open the door to user-created themes
• Continual updates to related themes as long as Azurra is online

We also added and updated a few themes:

• tvOS 13 is now based on Azurra/watchOS and is more usable in daily usage
• iOS 13 has a new dark theme based on what was seen at WWDC 2019
• watchOS 6 has some QoL improvements
• Windows Whistler is now based on Azurra/XP Luna and supports a wider range of desktops
• Windows Longhorn Aero ported via Azurra/Windows 7
• Windows Longhorn Jade ported via Azurra/Windows 7
• Windows Longhorn Plex ported via Azurra/XP Luna
• Windows Longhorn Slate ported via Azurra/XP Luna
• Windows Vista sees some enhancements
• Windows Server 2003 now based on Azurra/Windows 95
• Windows Server 2012 now based on Azurra/Windows 8.1
• Haiku R1 Beta 1 based on Azurra/BeOS R5
• B00merang Brome, a dark theme based on B00merang Flat

Enhancements to Android, Unity 8, B00merang Dark/Glass/Green/Circle/Flat, Windows 3.11, Windows 95, Windows 7, Windows 8.1, Windows 10, Solaris 10 Blueprint/CDE, Solaris 11, Fuchsia, Windows XP and more.

We expect to release the following soon:

• macOS 10.15 Catalina reusing Mojave code

What's planned:

• Ambiance based on Azurra/Unity 8
  Right now Ambiance is OK, but starting with Ubuntu 19.04, Yaru has replaced it as the default theme. Ambiance is also quite old and was never fully ported to GTK 3.20. We're aiming at creating a new codebase that reproduces the unique appearance of this original Ubuntu theme.
• Console theme
  It's a very interesting concept: how would your desktop look like if it was just a console?
• Aero Dark based on Windows 7 Media player
  It's sleek and retro, and on our TODO list for a while.
• Brilliance theme pack
  Ever heard of RAVEfinity? They made very good themes but ran out of time to dedicate to their project. We almost did the same a few years ago, but thanks to modularisation and code reusability practices we're still here.
  
  Since we have a reliable piece of software in the Azurra framework to generate an endless amount of themes, we wanted to bring back some of the best themes RAVEfinity offered while they released themes. B00merang Brome was partly generated using this variant of the Azurra framework pipeline.

We will update the website and download pages in the coming weeks to the newest versions available.

We hope you enjoy our themes as much as we enjoy creating them!