Linux support

[SergeevPavel]

• Requirements
  • Capable of running with both X11 and Wayland
    • We may implement both of them
    • Or investigate possibility of running in compatibility mode
  • Should be integrated with Skiko the same way as MacOS target does
  • Should support OpenGL backend, Vulkan is still too raw in Skia
  • At the beginning, should have a separate sample application. Later we will abstract some parts
  • Native part shouldn't depend on Skia, it should be pluggable from Kotlin
• Design notes
  • Keep an API surface small, but enough to implement functionality of Fleet Window manager and Compose
    • e.g. window creation might require number of calls to platform methods, it's better to group them in one create_window function
  • Keep API close to platform APIs
    • e.g. it's fine to have different attributes in events of similar type in different platforms
  • Code reuse between platforms is non-goal
    • Toolkit API in Kotlin should expose close to platform API, on top of that we will build a layer to abstract platform differences when possible. For now it's not clear where this abstraction layer will leave. It might be Fleet/Dock Window Manager, it might be part of Compose For Desktop, or it might be a part of desktop-toolkit library.
• Milestones [Kotlin APIs implemented]
  • 0. Setup infrastructure; Gradle tasks to build native, generate java boilerplate, setup demo app
  • 1. Application initialisation; Run event loop; Create a window
  • 2. Mouse events; OpenGL context, Skia integrated with Window context
  • 3. Basic keyboard
  • ...
• Proposed workflow
  • Working with code review in branch
  • Daily meetings with fixed time span to discuss current progress