package toffee

Changelog

[0.1.0] - Unreleased

Mosaic

Terminal UI framework for OCaml built on Matrix and Toffee. Implements The Elm Architecture (TEA) for declarative, composable terminal applications.

• The Elm Architecture – Pure functional Model-View-Update pattern with init, update, view, and subscriptions. Commands (Cmd) handle side effects; subscriptions (Sub) handle external events
• Flexbox and Grid layout – Powered by Toffee, define complex layouts with familiar CSS properties like flex_direction, align_items, justify_content, and CSS Grid support
• Rich widget library – box, text, input, textarea, select, tab_select, slider, table, spinner, scroll_box, canvas, code, markdown, tree, progress_bar, and line_number
• Rich text – Styled fragments, word/character wrapping, text selection, and full Unicode support
• Syntax highlighting – Tree-sitter-based code highlighting with the code widget
• Event system – Mouse, keyboard, paste, focus, and resize events with Sub.on_key, Sub.on_mouse, Sub.on_paste, Sub.on_resize, Sub.on_focus, and Sub.on_blur
• Canvas drawing – Procedural drawing API with shapes, lines, and braille patterns for charts and visualizations
• Markdown rendering – CommonMark rendering with the markdown widget
• Dirty tracking and viewport culling – Only re-layouts dirty subtrees; scroll containers cull off-screen children

Matrix

Terminal toolkit for OCaml providing rendering, input, and terminal management.

• Immediate-mode runtime – Matrix.run with on_frame, on_render, on_input, on_resize callbacks, configurable FPS capping, and safe teardown that restores terminal state even on exceptions
• Two display modes – Full-screen alternate buffer (Alt) or inline on primary screen (Primary) with dynamic height and full scrollback
• Declarative Image API – Notty-inspired compositional DSL with hcat, vcat, overlay, padding, cropping, and hit regions for mouse interaction
• Full Unicode support – Grapheme cluster handling, emoji, wide characters, and configurable width calculation (wcwidth, Unicode tables)
• Modern terminal protocols – Kitty keyboard (with auto-detection), SGR/X10/URXVT mouse tracking, bracketed paste, focus reporting—all negotiated automatically
• Native alpha blending – RGBA colors with proper alpha compositing for translucent overlays
• Double-buffered diffing – Screen module diffs cell changes between frames to emit minimal ANSI output
• PTY & VTE – Spawn processes in pseudo-terminals and embed terminal output in your UI; cross-platform with Windows ConPTY support
• Automatic capability detection – Two-stage probing (environment heuristics + active queries) detects RGB, Kitty keyboard, sixel, hyperlinks, and Unicode width support without manual configuration
• Hit testing – O(1) spatial indexing maps mouse coordinates to UI element IDs for clickable widgets
• Built-in devtools – Debug overlay for frame timing/FPS, frame dumps to disk for diagnostics

Toffee

CSS layout engine for OCaml, ported from Taffy (Rust).

• CSS Grid Level 1 – Full implementation including grid-template-columns/rows, grid-auto-flow, named lines/areas, repeat(), minmax(), fr units, and auto-placement
• Flexbox – Complete algorithm with flex-direction, flex-wrap, flex-grow/shrink/basis, align-items/self/content, justify-content, gap, and order
• Block layout – Traditional CSS block formatting context with proper margin collapsing
• Pure OCaml, zero dependencies – No C stubs, no runtime dependencies; works wherever OCaml 5 runs
• Arena storage and layout caching – Nodes stored in a flat arena; layout results cached and invalidated via mark_dirty
• Composable architecture – Use the high-level Toffee tree API or the lower-level toffee.tree and toffee.compute libraries to plug layout into your own node representation
• Custom measure functions – Integrate text shaping, images, or any content with intrinsic sizing via compute_layout_with_measure