Kasane

Drop-in Kakoune frontend with independent rendering, GPU backend, and WASM plugins.

_{Fuzzy finder, pane splits, and color preview are WASM plugins — no code in Kasane itself}

Getting Started · What's Different · Configuration · Using Plugins · Plugin Development · Plugin API · Vision

What You Get

Kakoune's -ui json protocol was designed to let external processes drive the UI, but its built-in terminal renderer leaves that potential untapped. Kasane rebuilds the rendering pipeline from scratch and opens it to plugins.

Your kakrc works unchanged. alias kak=kasane and these improvements apply automatically:

• Flicker-free rendering — independent pipeline at ~59 μs per frame
• Multi-pane without tmux — native splits with per-pane status bars
• Clipboard that just works — Wayland, X11, macOS, SSH forwarding
• Correct Unicode — independent width calculation, CJK and emoji handled

Opt in to smooth scrolling, GPU backend (--ui gui), themes, border styles, and search dropdown. Existing Kakoune plugins (kak-lsp, …) work as before. See What's Different for the full list.

Quick Start

Note

Requires Kakoune 2024.12.09 or later. Binary packages skip the Rust toolchain requirement.

Arch Linux: yay -S kasane-bin · macOS: brew install Yus314/kasane/kasane · Nix: nix run github:Yus314/kasane · From source: cargo install --path kasane

kasane file.txt               # your Kakoune config works unchanged
alias kak=kasane              # add to .bashrc / .zshrc

GPU backend: cargo install --path kasane --features gui, then kasane --ui gui.

See Getting Started for detailed setup.

Plugins

Kakoune's -ui json protocol decouples editor from renderer. Kasane builds on this with a plugin system that opens the full UI to extension — floating overlays, line annotations, virtual text, code folding, gutter decorations, input handling, scroll policies, and session management.

The repository includes example plugins you can try today:

Plugin	What it does
cursor-line	Highlight the active line with theme-aware colors
fuzzy-finder	fzf-powered file picker as a floating overlay
sel-badge	Show selection count in the status bar
color-preview	Inline color swatches next to hex values
pane-manager	Tmux-like splits with Ctrl+W — no external multiplexer needed
image-preview	Display images in a floating overlay anchored to the cursor
smooth-scroll	Animated scrolling
prompt-highlight	Visual feedback when entering prompt mode

Each plugin ships as a single .wasm file — sandboxed, composable, auto-cached. A complete plugin in 15 lines — here is sel-badge in its entirety:

kasane_plugin_sdk::define_plugin! {
    manifest: "kasane-plugin.toml",

    state {
        #[bind(host_state::get_cursor_count(), on: dirty::BUFFER)]
        cursor_count: u32 = 0,
    },

    slots {
        STATUS_RIGHT(dirty::BUFFER) => |_ctx| {
            (state.cursor_count > 1).then(|| {
                auto_contribution(text(&format!(" {} sel ", state.cursor_count), default_face()))
            })
        },
    },
}

Start writing your own:

kasane plugin new my-plugin    # scaffold from 5 templates
kasane plugin dev              # hot-reload while you edit

See Plugin Development and Plugin API.

Status

Kasane is stable as a Kakoune frontend — alias kak=kasane and use it daily. The plugin API is still evolving; expect breaking changes if you write plugins. The current WASM plugin ABI is kasane:plugin@0.23.0; plugins built against an older ABI must be rebuilt before they will load.

Usage

kasane [options] [kak-options] [file]... [+<line>[:<col>]|+:]

All Kakoune arguments work — kasane passes them through to kak.

kasane file.txt              # Edit a file
kasane -c project            # Connect to existing session
kasane -s myses file.txt     # Named session
kasane --ui gui file.txt     # GPU backend
kasane -l                    # List sessions (delegates to kak)

Configuration lives in ~/.config/kasane/config.toml:

[ui]
border_style = "rounded"   # single | rounded | double | heavy | ascii

[scroll]
smooth = true              # enable smooth scrolling (via plugin)

[search]
dropdown = true            # vertical dropdown instead of inline

See docs/config.md for the full reference.

Contributing

See CONTRIBUTING.md for development setup and guidelines.

cargo test                             # Run all tests
cargo clippy -- -D warnings            # Lint
cargo fmt --check                      # Format check

License

MIT OR Apache-2.0