Radiance 6.0.0 and looking ahead into the future

September 2nd, 2022

It gives me great pleasure to announce the next major release of Radiance. Let’s get to what’s been fixed, and what’s been added. First, I’m going to use emojis to mark different parts of it like this:

💔 marks an incompatible API / binary change
🎁 marks new features
🔧 marks bug fixes and general improvements

Dependencies for core libraries

  • Gradle: 7.2 ➡ 7.5.1
  • Kotlin: 1.5.31 ➡ 1.7.10
  • Kotlin coroutines: 1.5.2 ➡ 1.6.4


  • 🔧💔 A new direct rendering model for all core and custom components in Radiance
    • Instead of rendering components as multi-layer combinations of cached offscreen images, Radiance now uses direct rendering to the Graphics objects passed to the relevant UI delegates and painting methods
    • Use RadianceCommonCortex.paintAtScale1x for visuals that need to “fall” on exact pixels, line single-pixel borders, separators, etc
  • 🔧 Remove all usages of java.security APIs (that are deprecated in Java 17 going forward)


  • 🎁 New default animation pulse source that is based on the display refresh rate


  • 🎁💔 Unify fire action trigger logic for command buttons by replacing CommandButtonPresentationModel.isFireActionOnRollover and CommandButtonPresentationModel.isFireActionOnPress with a single actionFireTrigger enum that has three values:
    • OnRollover to fire action on rollover
    • OnPressed to fire action on press
    • OnPressReleased to fire action on press release (the default)
  • 🎁💔 Unify text action/popup click logic for command buttons by replacing CommandButtonPresentationModel.isTextClickAction and CommandButtonPresentationModel.isTextClickPopup with a single textClick enum field that has two values:
    • Action to activate action on text click
    • Popup to activate secondary content on text click
  • 🎁💔 Revisit breadcrumb bar APIs
    • Remove exception propagation APIs (they were no-op in any case since it wasn’t wired)
    • Remove index tracking in BreadcrumbItem (not wired to anything)
    • Switch BreadcrumbBarCallBack APIs from StringValuePair to BreadcrumbItem
    • Also rename getLeafs to getLeaves
    • Rename BreadcrumbBarCallBack to BreadcrumbBarContentProvider`
    • Rename BreadcrumbBarModel to BreadcrumbBarContentModel
    • Add BreadcrumbBarPresentationModel and support icon filtering
    • Remove StringValuePair from the API surface altogether
    • Revisit the API surface of BreadcrumbItem
  • 🎁💔 Switch presentation models to use BackgroundAppearanceStrategy across all components. This applies to
    • CommandButtonPresentationModel.setFlat
    • CommandButtonPresentationModel.Overlay.setFlat
    • CommandStripPresentationModel.setFlat
    • CommandPresentationModel.setFlat
  • 🎁 Add single row resize policy to ribbon flow bands
  • 🔧 Fix lost breadcrumb bar path after skin change
  • 🔧 Fix separator drawing over the last text character in MEDIUM command buttons that don’t display icons
  • 🔧 Command menus now toggle open and close on clicks
  • 🔧 Fix issues with command popup menus not closing in certain scenarios


  • 💔 Simplified visuals of tabbed panes
    • Remove SINGLE_FULL and DOUBLE_FULL from TabContentPaneBorderKind. Apps that wish to draw border around the content area will need to do so explicitly.
    • Remove RadianceSkin.setTabFadeStart and RadianceSkin.setTabFadeEnd and do consistent indication for the selected / rollover tab with no alpha fade gradient.
    • Consistent corner radius of tabs across all skins.
  • 💔 Clean up the signature of fill painters, removing isFocused (not used anywhere, and shouldn’t be since the focus indication is painted separately) and hasShine (specific to StandardFillPainter visuals).
  • 🔧 Fix issues with various color chooser panels, including the correct wiring of the “Reset” button across all the panels
  • 🔧 Fix incorrect bounds of maximized decorated frames on Windows
  • 🔧 Fix inverted logic of ComponentOrParentChainScope.setExtraWidgetsPresence
  • 🔧 Fix null pointer exception in rollover button listeners

SVG transcoder

  • 🔧 Simplify generated code by not emitting identity affine transforms
  • 💔 Remove plain templates

As always, I’d love for you to take this Radiance release for a spin. Click here to get the instructions on how to add Radiance to your builds. And don’t forget that all of the modules require Java 9 to build and run.

And now for the next big thing or two.

This release took almost a year to complete. I needed this time to figure out how to continue evolving Radiance in a meaningful way over the next decade or so. The considerations for what went into this work were laid out last October in this post. The two major areas I wanted to focus on are direct rendering and API consistency.

Direct rendering has touched the UI delegates for every single core Swing component, and almost every custom Radiance component, from command buttons all the way up to the ribbon. API consistency has been driven by the ongoing work in Aurora, as well as the drive to clean up the API surfaces that have been misaligned across the codebase for a while.

Making meaningful changes also means making hard choices about backwards compatibility. Deprecating existing APIs but leaving them available leads to a confusing API surface and increases the cost of maintaining and evolving the codebase. Leaving existing APIs in place, and trying to redirect them under the hood to a “v2” variant places noticeable constraints on what is feasible to do. If I want Radiance to be here in the next 10-15 years, the only practical way forward is to cut out APIs that have not aged well, remove them from the codebase and introduce new ones as necessary. I understand that it causes friction during dependency upgrades on the application side of things, but the only other alternative is abandoning any new development altogether.

With all this in mind, what is next, for 2023 and beyond?

The first major change in Radiance is going to be around defining and using colors. Code-named Chroma, this effort aims to bring more clarity and control over working with colors in core and custom Radiance skins, inspired by the ongoing evolution of design systems such as Material and others.

This change will also find its way into Aurora, as these two projects are twins, in a sense. Once Compose for Desktop hits its official 1.2 release, Aurora will go to 1.2 as well. Afterwards, I will work on window APIs, and will start the long-planned work to port the ribbon component to Aurora.

And last but most definitely not the least, are the plans to explore the third twin to Radiance and Aurora, and bring the theming layer and all the components to the world of Flutter.

As I said last October, it’s going to be a long road, and it may take a bit of time again until the next major release of Radiance. The current goal is to fully complete the color work across both Radiance and Aurora, and have them released at the same time. This will probably happen after the ribbon component is added to Aurora. As for the Flutter twin, it is going to be an exciting, and yet completely unpredictable adventure. I may or may not have something for you to play with in 2023. Time will tell.