Medja

Historical C# UI framework for embedded-style applications, separating control behavior from rendering to support headless interaction testing and SkiaSharp/OpenGL integration through OpenTK.

Developed primarily in 2018-2021 with support from SprintWORX GmbH, which authorized publication of the Medja source. Daniel Bişar (credited as Daniel Klafft in earlier history) designed and implemented substantial parts of the framework, alongside the contributors acknowledged below.

Historical demo: control state, layout and behavior are independent of the theme-specific rendering shown here.

Status: preserved for architectural and educational value, with targeted correctness and reproducibility maintenance rather than an active product roadmap. The CPU-only tests run on modern .NET; the graphics backend remains a legacy .NET Framework/Mono stack. See build and verification.

Engineering highlights

• Testable UI behavior: layout, focus, selection and keyboard/mouse input can be exercised without a window or graphics context.
• Property and binding infrastructure: typed properties, change notification, one-/two-way binding, attached properties and change tracking.
• Rendering separation: control factories and renderer abstractions connect the control model to themes without putting graphics calls in control logic.
• Graphics/native integration: SkiaSharp drawing, OpenTK input/window integration, OpenGL components, context management and resource lifecycles.
• Performance/debugging experiments: graph downsampling, rendering invalidation, dispatcher queues and native rendering prototypes. Historical measurements are workload-specific notes, not a claim of superiority to WPF.

Start with the headless text-editor tests, binding tests, or demo application.

Architecture

Controls / layout / input       Medja
          |
Property / binding layer       Medja.Properties
          |
Renderer abstraction / themes  Medja.Theming + Medja.OpenTk.Themes
          |
OpenTK window/input + SkiaSharp drawing + OpenGL components

The diagram shows responsibilities, not a strict runtime call sequence. Controls use properties to signal state changes; factories attach renderers. Tests can use a plain control factory without the native graphics layer.

Module	Responsibility
Medja	Controls, layout, input state, primitives and rendering contracts
Medja.Properties	Properties, bindings and change tracking
Medja.Utils	Collections, IO, threading and supporting utilities
Medja.OpenTk	Window/input adaptation and SkiaSharp/OpenGL integration
Medja.OpenTk.Themes	Theme-specific renderers
Medja.ProtoBuf, Medja.ZeroMQ	Optional serialization/messaging integrations

Current status

Main implementation history spans 2018-2021, with publication/build adjustments in 2022 and focused maintenance in 2026. This is not a newly launched or production-supported UI toolkit.

Scope	Current verification
Headless behavioral tests	Executed on Linux x86-64 with .NET SDK 10.0.112; CI runs the same CPU-only suites
Core libraries	Preserve their netstandard2.0 targets
Graphics backend, themes and maintained examples	Compile against net472; this does not verify graphics runtime behavior
GUI runtime	Historically developed mainly on Linux/Mono; current rendering, touch devices, Windows and macOS are not revalidated
Native Linux graphics	Committed SkiaSharp binary is x86-64 only; no current ARM/ARM64 support claim

Quick start

Install .NET SDK 10.0.112, matching global.json, then run from the repository root:

bash build/test_headless.sh

This restores, builds and executes the control, utility, property, protobuf and ZeroMQ-prefix tests without Mono, a display or a GPU. ZeroMQ-prefix tests do not open native sockets. GitHub Actions verifies this supported headless scope.

To compile the main visual demo:

dotnet restore src/examples/demo/demo.csproj
dotnet build src/examples/demo/demo.csproj --configuration Release --no-restore

Running that net472 executable additionally requires a compatible .NET Framework/Mono runtime and graphics/native libraries. Those runtime combinations are not covered by the headless CI; see build instructions and the example index.

Limitations

• No current cross-platform/device support matrix or comparative WPF benchmark.
• Graphics dependencies are intentionally historical. The committed native SkiaSharp 1.68.0 binary and managed 1.68.2.1 pairing needs runtime validation.
• Markup/designer tooling, validation and some controls remain incomplete.
• Production Graph2D rendering is incomplete; the graph example uses its own small synthetic-data renderer.
• The generic MedjaSerializer scaffold is explicitly unsupported; this does not affect the separate tested protobuf reader/writer.
• Some prototypes retain obsolete APIs or incomplete code. Their status is documented rather than presented as supported features.

Historical documentation

Documentation index includes architecture notes, experiment records, control-authoring guidance, testing, and archival asset context. Old design goals and marketing material are retained as history, not a current roadmap or verified support claim.

Attribution and licensing

Thank you to SprintWORX GmbH for supporting the work and allowing publication. Historical company copyright remains in the MIT license.

Contributors and supporters include Daniel Bişar / Daniel Klafft, Matthias Fritsch (SprintWORX GmbH), and Jan Schmitt / @lockejan (control development). Git history records individual contributions; this repository does not imply sole authorship of every component.

The README historically referenced lockejan's secure-text-editor as a user of Medja; current compatibility is not asserted.

Dependencies and embedded fonts retain their own licenses, including LGPL components. See third-party notices and native provenance; the entire dependency stack is not MIT.