“When you design a new user interface, you have to start off humbly”

— Steve Jobs presenting Aqua

Humble UI is a desktop UI framework for Clojure. No Electron. No JavaScript. Only JVM and native code.

Goal

• A way to build high-quality desktop UIs
• Build better apps that’s possible with web now, while staying cross-platform
• Build them faster in Clojure

Motivation

• Create desktop apps in Clojure
• Electron is a great landmark
  • People prefer native apps to web apps
    • Normal shortcuts, icon, its own window, file system access, notifications, OS integrations
  • Developing real native apps is expensive
  • JavaScript + Chrome have huge overhead, can be slow
• Java has “UI curse”
  • Previous attempts were cumbersome for user
  • Mimicking native look and feel didn’t work
  • Looked bad
• Time of declarative UIs is now
  • React
  • Flutter
  • SwiftUI
  • Jetpack Compose
• Web + Electron cleared the way for non-native look and feel
  • Write once, run everywhere is no longer rejected by users
  • Even native apps have many custom UI elements
• Flutter proved new UI stack is a feasible task
• Clojure is the best language for UI development
  • Performant enough to not noticeably lag
  • Access to full power of your computer (multithreaded)
  • REPL + interactive development == instant feedback loop
  • Proven itself great in CLJS world, can do the same on desktop

How is it going to be different

• No goal to look native, aim for web look (write once, run everywhere)
• Embrace platform differences in OS integration
• Declarative UI API is much more pleasant to work with (+plays well with FP)
• Expose low-level APIs along with high-level API
  • People can solve non-trivial problems in their own way, without hacks
• Superpowers of Clojure

Architecture

• Leverage Skia via Skija for high-performance GPU-accelerated graphics
• JWM (Java Window Manager) for OS integration (simple, common ground, embrace the differences)

Status

Work in progress. No docs, and everything changes every day.

Resources

Slack:

• #humbleui on Clojurians Slack (invite here)

Posts:

• Thoughts on Clojure UI framework
• Humble Chronicles: Decomposition
• Humble Chronicles: The Layout
• Humble Chronicles: Developer Experience

Videos:

• Wordle in Clojure with Humble UI

Sample apps:

• tonsky/humble-ants
• tonsky/humble-deck
• lilactown/humble-starter
• oakmac/humble-mondrian
• oakmac/humble-modal-example
• oakmac/humble-animations
• LuisThiamNye/humbleui-explorations
• Folcon/FE-7drl-2022

Development

Run REPL server:

./script/repl.py

To reload demo app using tools.namespace, evaluate:

(user/reload)

Examples

(require '[io.github.humbleui.ui :as ui])

(def ui
  (ui/default-theme {}
    (ui/center
      (ui/label "Hello from Humble UI! 👋"))))

(ui/start-app!
  (ui/window
    {:title "Humble 🐝 UI"}
    #'ui))