Par Term Emu Core Rust

A comprehensive terminal emulator library written in Rust with Python bindings for Python 3.12+. Provides VT100/VT220/VT320/VT420/VT520 compatibility with PTY support, matching iTerm2's feature set.

What's New

Note: For the complete release history, see CHANGELOG.md. The entries below cover the most recent releases; the full history for older versions lives in CHANGELOG.md.

Version 0.56.0 is a minor release with Rust-embedder breaking changes: the 29 deprecated Terminal macro/trigger forwarders are removed on the 0.54.0 schedule (use terminal::MacroEngine/TriggerEngine; the Python API is unchanged), TermKeyEvent.key is now a plain u16 validated via TermKey::from_raw (an invalid discriminant is Unknown, not UB), and KittyParser::get_data returns Result. Headline additions: the C FFI on-device embedding surface (terminal_feed/terminal_dirty_ranges/pinned-buffer row readback/terminal_encode_key, with a cbindgen-generated, drift-gated terminal_core.h and make xcframework for iOS), per-consumer damage generations (Python damage_generation()/dirty_rows_since(); FFI ABI v2), par-mux rename-session/kill-session, and triggers that observe written text rather than render damage. Security: the par-mux host probe never runs repo-configured code (SEC-115), the Kitty path is bounded end to end against decompression bombs (SEC-116), and FFI string lengths always equal strlen (SEC-117). See CHANGELOG.md for complete release notes.

Version 0.55.0 is a minor release whose headline is the scheduled removal of the deprecated Terminal screenshot/benchmark forwarders (Rust embedders only): Terminal::screenshot/screenshot_to_file and Terminal::benchmark_rendering/benchmark_parsing/benchmark_grid_ops/run_benchmark_suite are gone, as promised by 0.54.0's deprecation schedule — use the crate::screenshot::render_terminal/save_terminal free functions and terminal::TerminalBenchmarks. The Python API surface is unchanged. Also ships the par-mux agent-telemetry enabler: a pane.report_agent_telemetry hook endpoint, telemetry served on list-agents rows with the %agent-telemetry-changed broadcast, and a host telemetry probe (disk-free percent and git state per pane cwd) swept by the daemon itself. See CHANGELOG.md for complete release notes.

Version 0.54.0 is a minor release with one Rust-embedder breaking change: the headless sim cargo feature no longer implies screenshot, so --features sim builds now compile without the swash font-shaping stack and the ~700 KB of embedded fonts; render-capable embedders add features = ["sim", "screenshot"].

Version 0.54.0 closes the audit's hardening tail: the headless sim profile no longer compiles the screenshot renderer or pulls its font stack (breaking for Rust embedders — add features = ["sim", "screenshot"] to keep it), PtyTerminal gains set_allow_file_media/get_allow_file_media so every embedder path can gate Kitty file media, StreamingServer::with_config now actually applies its kitty_file_media setting, and the streamer rate-limits client input by default (1 MiB/s; pass --input-rate-limit 0 to lift it). Macro and trigger logic moved onto MacroEngine/TriggerEngine services with deprecated Terminal forwarders, screenshot docs are verified against the stub by CI, and PTY consumers get a wait-free size/cursor mirror. See CHANGELOG.md for complete release notes.

Version 0.52.0 is a minor release hardening the par-mux daemon: it now outlives the terminal that started it, survives listener faults with a final save, raises its file-descriptor limit at start, guards the shared-/tmp socket fallback (behavior-affecting: the fallback socket path moved into a per-UID directory), and resumes agents correctly on Windows. Panes gained session/window identity env vars, a per-session environment (set-environment, new-session -e), split-window -c/new-window -c, and name-based -t targets. PaneFactory::create_pane now takes a &SpawnContext (breaking for embedders), and PTY output callbacks now fire after the bytes are applied to the terminal (behavior-affecting). See CHANGELOG.md for complete release notes.

Version 0.51.0 is a minor release adding par-mux client mode (par-mux --cmd), MuxClient::send_checked, mux-backed streaming sessions (par-term-streamer --mux-socket, MuxSessionFactory), a pane-info mux command, a web-frontend size policy for viewers of a shared pane, a PATH fallback for locating the par-mux daemon, and a macOS fix for PTY output lost when a child exits before its output is read. Phones no longer resize a plain streaming session's PTY on connect. See CHANGELOG.md for complete release notes.

Version 0.50.0 is a minor release with two breaking changes: the dead terminal multiplexing module (PaneState/WindowLayout/SessionState and the Terminal pane-state methods) is removed from the Rust and Python surfaces, and poll_events()/poll_subscribed_events()/observer callbacks now return native Python types instead of stringly-typed dicts (a poll_events_legacy()/poll_subscribed_events_legacy() bridge keeps the old shape available for one release). The par-mux daemon gained its full Phase 2–6 command, agent, and resume work, plus post-release fixes for reattach scrollback, daemon-restart screen state, and a blank-split-pane bug; the streaming server picked up read-only-mode enforcement, a WebSocket handshake timeout, TLS/Basic-auth/CSP hardening, and clickjacking protection headers. See What's New in 0.50.0 below, and CHANGELOG.md for complete release notes.

What's New in 0.50.0

Version 0.50.0 is a minor release whose headline is two breaking changes — a Python API removal and a Python event-dict type change — plus the par-mux Phase 2–6 daemon work, a round of post-release par-mux bug fixes, and streaming-server security hardening.

• Removed (breaking): the terminal multiplexing module — PaneState, WindowLayout, SessionState, and the Terminal pane-state methods (capture_pane_state and friends) — is gone from the Rust API and the Python bindings. It had zero callers in the codebase, its capture was plain rendered text (Vec<String>: no colors, attributes, scrollback, or alternate screen), and restore_pane_state restored only size/title/cursor by its own comment. replay_snapshot.rs's TerminalSnapshot already captures everything a real persistence format needs, and par-mux Phase 3's on-disk format started from that type; no consumer of the removed API existed to migrate.
• Changed (breaking): poll_events(), poll_subscribed_events(), and observer callbacks now return native Python types in their event dicts — numeric fields are int, booleans are bool, and unset optional fields are None instead of omitted — where every field was previously a string ("true"/"false" for booleans, omitted keys for unset optionals). poll_events_legacy() / poll_subscribed_events_legacy() are byte-identical to the old string-typed output and are kept for one release to ease migration.
• Added — par-mux daemon lifecycle: a kill-server command and par-mux --stop/--restart flags (previously the only way to stop the daemon was finding its PID and sending SIGTERM); a version command reporting the daemon's build stamp (<crate version>+<git sha[-dirty]>) so a stale long-lived daemon is detectable; and automatic reaping of panes whose child process exited on its own, which previously sat frozen in the tree forever.
• Added — par-mux pane titles and application-keypad tracking: select-pane -T/%pane-title-changed/pane-title, persisted across restart; ESC =/ESC > (DECPAM/DECPNM) application keypad mode is now tracked, snapshotted, and restored on both the Rust and Python surfaces.
• Added — par-mux capture-pane -e and a full-state reattach seed: styled -e capture with SGR escape bytes inline, and refresh-client -t now replays the full export_screen_restore_sequence() (cursor, input modes, alt-screen selection, and — as of the post-release fix below — scrollback) instead of just the styled screen.
• Added — PtyTerminal.wait_for_update()/wait_for_text(): condition-variable-backed blocking waits for applied PTY content, releasing the GIL, replacing time.sleep polling in test and automation code.
• Added — par-mux Phase 2–6 command, agent, and resume work (Rust mux feature): the pane/window/session command set (split-window, select-pane, resize-pane, swap-pane, lifecycle broadcasts, tmux-contract send-keys), the Phase 5 agent layer (herdr-compatible JSON hook reports, %agent-state-changed with hook/scrape provenance, the list-agents roster, and a scrape tier for claude/codex/grok panes without hooks), and Phase 6 agent-session resume (session identity persists across restarts and a restarted daemon respawns agent panes through their resume invocations).
• Fixed — par-mux, post-release: the reattach seed now replays scrollback instead of only the visible screen; a restarted daemon returns a full-screen pane (htop, top) to the main screen instead of a frozen alternate screen; a split pane's output now reaches clients (new splits previously rendered blank); and the command grammar accepts quoted session/window names containing spaces.
• Fixed — the alternate screen no longer reflows on resize (Rust + Python API): a width change previously reflowed the alt screen exactly like the main screen, scrambling full-screen TUIs (ratatui, curses) that redraw only what they believe changed. The alt screen now truncates/pads in place, matching xterm/tmux; main-screen reflow is unchanged.
• Security — streaming server hardening: read-only clients can no longer mutate shared state via Resize/FocusChange/Selection/Clipboard messages; WebSocket handshakes are timeout-bounded and count against max_clients before completing; TLS private-key permission checks now also cover --tls-pem; HTTP Basic auth verification runs at constant time regardless of username; secrets no longer appear in Debug output; X-Frame-Options/CSP headers are sent on every response (clickjacking defense); session ids are validated before reaching the session registry; and Input/Paste payloads are size-capped with PTY writes off the async runtime. See CHANGELOG.md for the full SEC-001 through SEC-011 list.

See CHANGELOG.md for complete release notes.

What's New in 0.49.0

Version 0.49.0 is a minor release focused on graphics placement fidelity, recording interoperability, and web-terminal rendering. Added: export_asciicast_v3() exports recordings in the asciicast v3 format — nested term header, relative per-event intervals, "COLSxROWS" resize strings — with a g graphics event per graphic that entered the store during the recording (live placements plus scrollback promotions) carrying protocol, geometry, position, and base64 RGBA pixels the text-only stream cannot convey. Parameterized XTPUSHCOLORS/XTPOPCOLORS slot forms: CSI Pi # P stores the current dynamic + ANSI palette into slot Pi (1–10) without pushing and CSI Pi # Q restores it without popping, with stores past the current depth growing the stack and padding intermediate slots with current-color snapshots. DECSDM sixel display mode (CSI ? 80 h/l): set mode paints sixel graphics at the home position without scrolling or moving the cursor (xterm/mlterm/WezTerm semantics), reset keeps the default cursor-relative scrolling placement; DECRQM reports mode 80, DECSTR/RIS restore the default. Kitty display placements (a=T/a=p) now advance the cursor to the first line below the image, spanning the placement's row count via the ordinary newline path — scroll region and scrollback promotion apply as for a multi-row text write; C=1 suppresses the move (chafa and similar emitters), and virtual placements (U=1) never move the cursor. The web terminal frontend renders Sixel DCS q and iTerm2 OSC 1337 inline images via @xterm/addon-image (Kitty pixel placements remain unsupported by xterm.js). No breaking changes for Python or Rust consumers.

What's New in 0.48.0

Version 0.48.0 is a minor release focused on Kitty graphics protocol fidelity, driven by Herdr's image output. Added: placement geometry metadata — lowercase x=/y=/w=/h= are parsed as the source crop rectangle and preserved as new source_x/source_y/source_width/source_height fields on ImagePlacement (included in the JSON graphics export), while uppercase X=/Y= are the within-cell display offsets; previously lowercase x=/y= were misread as cell offsets, losing the crop entirely. Redisplaying an explicit nonzero (i=, p=) pair is now an upsert instead of a duplicate. Fixed: Kitty APCs process in stream order so interleaved cursor moves position each image slice (previously every slice stacked at one position); d= delete commands resolve after the full key=value list, so d= preceding i=/p= (Herdr's order) no longer silently no-ops; explicit c=/r= footprints govern row spans, graphics_at_row, and scroll/scrollback behavior instead of native pixel sizes; an omitted c=/r= axis is computed from the cropped source aspect ratio per the protocol; and retransmitting an image ID deletes its previous placements (including scrollback and animation state) as the spec requires, ending duplicate placements on session replay. Changed — breaking for Rust rlib consumers only: TerminalGraphic::height_in_rows now takes (fallback_cell_width, fallback_cell_height); the method is not exposed to Python. See CHANGELOG.md for complete release notes.

What's New in 0.47.0

Version 0.47.0 is a minor release focused on VT-sequence fidelity, security hardening, and Python ergonomics. Added: the XTPUSHCOLORS/XTPOPCOLORS/XTREPORTCOLORS color palette stack (CSI # P/Q/R — previously CSI # P misrouted to DCH and deleted characters); legacy alternate-screen modes 47, 1047 and 1048 (only 1049 was wired, so apps hardcoding the legacy modes got no screen switch); X10 mouse tracking (DECSET 9 — the mode existed but no DECSET arm ever set it); DECSACE stream-vs-rectangle extent for DECCARA/DECRARA; OSC 1337;CurrentDir= as an iTerm2 working-directory alias for OSC 7; Terminal.diff_snapshots() returning a SnapshotDiff (the class existed but no binding produced one); genuine Python type stubs (py.typed + generated _native.pyi — 69 classes, 1,335 methods, 342 properties); a criterion VTE throughput benchmark suite (make bench, committed baseline); and a vitest harness for the web frontend. Security: streaming-server HTTP CORS no longer falls back to very_permissive when no origin allowlist is configured and the /sessions endpoint gained the WS origin guard; the Kitty file-transmission .. check is component-wise (no longer rejects my..notes.png); debug-log temp files are PID-suffixed with 0600 and O_NOFOLLOW. Fixed: asciicast v2 export timestamps were 1000× too small (ms misread as µs); both WebSocket server paths (tungstenite and axum) now complete the RFC 6455 closing handshake instead of dropping with a bare FIN (clients saw 1006); Kitty placement APCs now store their decoded graphics; get_word_at/select_word are display-column correct for CJK/emoji; tests/test_streaming.py passes again under the streaming build. Changed — breaking for Rust rlib consumers only: MSRV raised 1.90 → 1.98 (PyPI wheel users unaffected), dead APIs removed from the rlib surface (none were exposed to Python), streaming codec conversions are macro-generated (ConnectedBuilder replaces five partial constructors — old ones deprecated one release), and src/streaming/server.rs was decomposed with types re-exported at their old paths. See CHANGELOG.md for complete release notes.

What's New in 0.46.0

Version 0.46.0 is a minor release focused on a headless build profile and a logging fix. Added: the sim cargo feature — a headless terminal profile that compiles only grid + terminal + screenshot (no PTY, Python, or streaming), for pure-Rust embedders that vendor the crate as a server-side screen model (e.g. par-hack's char-mode simulation) without spawning real processes. The real-PTY backend is now gated behind a new pty_session feature that makes portable-pty and nix optional; python (the PyPtyTerminal binding) and streaming-bin (the server binary) auto-enable pty_session, so the default build, the PyPI wheel, and par-term-streamer are behaviorally unchanged. Consume with cargo build --no-default-features --features sim. Fixed: the Rust debug log now writes to the system temp dir (std::env::temp_dir()) instead of a hardcoded /tmp/... — on macOS the Rust log previously landed in /tmp while the Python TUI's log went to the per-user temp dir; both now agree (Linux is unchanged). Internal: removed the gitnexus/graphify dev-tooling integrations. Non-breaking for Python and Rust consumers. See CHANGELOG.md for complete release notes.

What's New in 0.45.0

Version 0.45.0 is a minor release focused on host-integrated window reporting, a TUI rendering fix, and a broad dependency refresh. Added: host-supplied window state for XTWINOPS reports — the headless core previously hardcoded CSI 11 t to always report non-iconified and CSI 13 t / CSI 13 ; 2 t to report position (0, 0); GUI hosts (e.g. par-term) can now call set_window_iconified(bool) / set_window_position(x, y) (with window_iconified() / window_position() getters) so these reports reflect the real on-screen window. Defaults are unchanged when the host never calls the setters, and a negative host-supplied coordinate is clamped to 0 in the CSI 13 t reply (CSI parameters are unsigned). Exposed on both Python Terminal and PtyTerminal. Changed: MSRV raised 1.88 → 1.90 — breaking for direct Rust rlib consumers only (no dependency requires it; set to a recent stable for broader compatibility); PyPI (Python wheel) users are unaffected, and the Linux glibc floor stays at 2.17 (manylinux2014). Fixed: a generation-counter race in PtySession where the counter could advance before the grid was written, letting a renderer stamp its cell cache with the already-advanced generation over not-yet-updated grid content — when that read was the last of an output burst, the counter never advanced again and partial regions froze until the next keypress/resize (visible in full-screen editors/pagers that repaint via partial line edits: joe, vim DL/IL/EL). A second generation bump now runs after the grid write, while the pre-processing bump is retained to preserve the issue #60 liveness guarantee. Dependencies: Rust cargo update (5 minor + 39 patch, no majors), Python (uv lock --upgrade: pillow, maturin, pyright, pytest, ruff), and web frontend (ncu: patch bumps + pako 2 → 3, with a one-line import fix in lib/protocol.ts); TypeScript held at 6.0.3. See CHANGELOG.md for complete release notes.

What's New in 0.44.0

Version 0.44.0 is a minor release focused on terminal-reporting completeness, security hardening, and concurrency. Added: OSC 99 Kitty desktop notifications (OSC 99 ; <metadata> ; <payload> ST) with multi-chunk accumulation, urgency, and actions — exposed to Python via the new take_notifications_detailed() method and Notification class (the existing take_notifications()/drain_notifications() tuple API is unchanged); XTGETTCAP (DCS + q) replying terminal capabilities (TN/Co/RGB/Tc); DECRQSS (DCS $ q) replying current SGR / cursor-style / scroll-margin settings; and XTWINOPS report ops CSI 11 t / 13 t / 19 t (window state / position / size-in-characters). Fixed: a DCS routing bug where DCS +q (XTGETTCAP) and DCS $q (DECRQSS) were misrouted into the Sixel parser because routing keyed only on the final q byte. Security: Kitty PNG and iTerm2 image decoding now enforce a shared MAX_IMAGE_PIXELS product cap (closing a decompression-bomb DoS reachable from any terminal/SSH bytes), and the streaming-server CLI hides api_key / http_password / http_password_hash values from --help. Performance: observer/trigger callback dispatch and PTY device-query reply writes moved outside the Terminal write lock (the reader thread previously held the exclusive guard across blocking PTY writes and Python re-entry, stalling every concurrent reader), screenshot glyph bitmaps are shared via Arc<[u8]> instead of per-character deep copies, and the per-row String allocation in flag-emoji detection is gone. Refactored (internal, no API change): the 4,004-line python_bindings/types.rs god-file was split into 12 cohesive submodules behind an unchanged facade, and the duplicated WS/WSS handshake logic was consolidated into a single shared callback factory. Non-breaking for Python and Rust consumers. See CHANGELOG.md for complete release notes.

Full history: CHANGELOG.md — every release from 0.9.0 through 0.43.0 is documented there (older README release notes were merged into the changelog).

Features

Core Terminal Emulation

• VT100/VT220/VT320/VT420/VT520 Support - Comprehensive terminal emulation matching iTerm2
• Rich Color Support - 16 ANSI colors, 256-color palette, 24-bit RGB (true color)
• Text Attributes - Bold, italic, underline (5 styles), strikethrough, blink, reverse, dim, hidden
• Advanced Cursor Control - Full VT cursor movement and positioning
• Line/Character Editing - VT220 insert/delete operations
• Rectangle Operations - VT420 fill/copy/erase/modify rectangular regions (DECFRA, DECCRA, etc.)
• Scrolling Regions - DECSTBM for restricted scrolling areas
• Tab Stops - Configurable tab stops (HTS, TBC, CHT, CBT)
• Unicode Support - Full Unicode including complex emoji sequences and grapheme clusters
  • Variation selectors (emoji vs text presentation)
  • Skin tone modifiers (Fitzpatrick scale U+1F3FB-U+1F3FF)
  • Zero Width Joiner (ZWJ) sequences for multi-emoji glyphs
  • Regional indicators for flag emoji
  • Combining characters and diacritical marks

Modern Features

• Alternate Screen Buffer - Full support with automatic cleanup
• Mouse Support - Multiple tracking modes and encodings (X10, Normal, Button, Any, SGR, URXVT)
• Bracketed Paste Mode - Safe paste handling
• Focus Tracking - Focus in/out events
• OSC 8 Hyperlinks - Clickable URLs in terminal (full TUI support)
• OSC 52 Clipboard - Copy/paste over SSH without X11
• OSC 9/777/99 Notifications - Desktop-style alerts and notifications, including Kitty's OSC 99 protocol (chunked payloads, urgency levels, actions) via take_notifications_detailed()
• Terminal Capability Queries - XTGETTCAP (DCS + q) capability lookup and DECRQSS (DCS $ q) SGR/cursor-style/scroll-margin introspection
• Expanded XTWINOPS Reporting - CSI 11/13/19 t report window state, position, and screen size in characters
• Shell Integration - OSC 133 (iTerm2/VSCode compatible), OSC 1337 RemoteHost for remote host detection
• Semantic Buffer Zones - OSC 133 FinalTerm markers partition scrollback into prompt, command, and output zones
• Command Output Capture - Extract text from specific command execution blocks via get_command_output() and get_command_outputs()
• Semantic Snapshot API - Structured terminal state extraction via get_semantic_snapshot() for AI/LLM consumption, with configurable scope (visible, recent, full) and JSON output
• Kitty Keyboard Protocol - Progressive keyboard enhancement with auto-reset on alternate screen exit
• Synchronized Updates (DEC 2026) - Flicker-free rendering
• Tmux Control Protocol - Control mode integration support
• Observer API - Push-based event delivery with sync callbacks and async queues; convenience wrappers for common patterns (bell, title, CWD, command completion, zone changes)
• General-purpose File Transfer - OSC 1337 File= with inline=0 for host-to-terminal downloads, RequestUpload for terminal-to-host uploads, with progress tracking and lifecycle events
• Instant Replay - Cell-level terminal snapshots with input-stream delta recording, size-based eviction, and timeline navigation via SnapshotManager and ReplaySession
• C-Compatible FFI - embedding API in include/terminal_core.h (terminal_create/feed/dirty_ranges/read_row render loop, key encoding, snapshots, observers; SharedState/SharedCell) for C/C++ and Swift apps — see the FFI Guide and make xcframework for iOS

Graphics Support

• Sixel Graphics - DEC VT340 compatible bitmap graphics with half-block rendering
• iTerm2 Inline Images - OSC 1337 protocol for PNG, JPEG, GIF images
• Kitty Graphics Protocol - APC G protocol with image reuse, animations, zlib compression (o=z), and advanced placement; the t=f/t=t file media is security-gated (set_allow_file_media, default allows only spec-named *tty-graphics-protocol* temp files, deleted only after decoding)
• Unicode Placeholders - Virtual placements insert U+10EEEE characters for inline image display
• Unified Graphics Store - Protocol-agnostic storage with scrollback support
• Animation Support - Frame-based animations with timing and composition control
• Resource Management - Configurable memory limits and graphics dropped tracking

PTY Support

• Interactive Shell Sessions - Spawn and control shell processes
• Bidirectional I/O - Send input and receive output
• Process Management - Start, stop, and monitor child processes
• Dynamic Resizing - Resize with SIGWINCH signal
• Environment Control - Custom environment variables and working directory
• Event Loop Integration - Non-blocking update detection
• Cross-Platform - Linux, macOS, and Windows via portable-pty

Terminal Streaming (WebSocket)

• Standalone Server - Pure Rust streaming server binary (no Python required)
• Real-time Streaming - Sub-100ms latency terminal streaming over WebSocket
• Multiple Clients - Support for concurrent viewers per session
• Authentication - Optional API key authentication (header or URL param)
• Configurable Themes - Multiple built-in color themes (iTerm2, Monokai, Dracula, Solarized)
• Auto-resize - Client-initiated terminal resizing with SIGWINCH support
• Browser Compatible - Works with any WebSocket client (xterm.js recommended)
• Modern Web Frontend - Next.js/React application with Tailwind CSS v4 and xterm.js

Terminal Multiplexer (par-mux)

• tmux Control Mode - Sessions, windows, and split panes served over a local socket, attachable by tmux control-mode clients
• Real-Time Push - Pane output streams to clients as bytes arrive; no polling
• Agent Awareness - Panes report agent state over the same socket (JSON hook reports), with a scrape fallback for agents without hooks and an agent roster query
• Session Resume - Agent session identity persists across daemon restarts; agent panes respawn through their resume invocations
• Crash-Safe State - Atomic saves with quarantine of unreadable state files; a clean SIGTERM never loses the last window

Screenshots and Export

• Multiple Formats - PNG, JPEG, BMP, SVG (vector); HTML via export_html()
• Embedded Font - JetBrains Mono bundled - no installation required
• Programming Ligatures - =>, !=, >=, and other code ligatures
• True Font Rendering - High-quality antialiasing for raster formats
• Color Emoji Support - Full emoji rendering with automatic font fallback
• Session Recording - Record/replay sessions (asciicast v2, JSON)
• Export Functions - Plain text, ANSI styled, HTML export

Macro Recording and Playback

• YAML Format - Human-readable macro storage format
• Friendly Key Names - Intuitive key combinations (ctrl+shift+s, enter, f1, etc.)
• Keyboard Events - Record and replay keyboard input with precise timing
• Delays - Control timing between events
• Screenshot Triggers - Trigger screenshots during playback
• Playback Controls - Play, pause, resume, stop, and speed control
• Macro Library - Store and manage multiple macros
• Recording Conversion - Convert terminal recording sessions to macros

Utility Functions

• Text Extraction - Smart word/URL detection, selection boundaries, bracket matching
• Content Search - Find text with case-sensitive/insensitive matching
• Buffer Statistics - Memory usage, cell counts, graphics count and memory tracking
• Color Utilities - 18+ color manipulation functions (iTerm2-compatible)
  • NTSC brightness, contrast adjustment, WCAG accessibility checks
  • Color space conversions (RGB, HSL, Hex, ANSI 256)
  • Saturation/hue adjustment, color mixing

Documentation

• Quick Start Guide - Get running in minutes
• API Reference - Complete Python API documentation
• VT Sequences - Comprehensive ANSI/VT sequence reference
• Advanced Features - Detailed feature guides
• Architecture - Internal architecture details
• Security - PTY security best practices
• Building - Build instructions and requirements
• Configuration Reference - Configuration options
• Cross-Platform Notes - Platform-specific information
• VT Technical Reference - Detailed VT compatibility and implementation
• Fonts - Font configuration and rendering
• Macros - Macro recording and playback system
• Streaming - WebSocket terminal streaming
• Multiplexer - par-mux terminal multiplexer daemon
• Rust Usage - Using the library in pure Rust projects
• Observers - Push-based event delivery (callbacks and asyncio queues)
• Instant Replay - Cell-level snapshots and timeline navigation
• FFI Guide - C-compatible embedding API for Swift/JNI/C/C++
• Graphics Testing - Testing graphics protocol implementations

Installation

From PyPI

uv add par-term-emu-core-rust
# or
pip install par-term-emu-core-rust

Wheels ship with the streaming server compiled in (StreamingServer works out of the box; check par_term_emu_core_rust._native.HAS_STREAMING to detect a build without it).

From Source

Requires Rust 1.98+ and Python 3.12+:

# Install maturin (build tool)
uv tool install maturin

# Build and install
maturin develop --release

Building a Wheel

# --features streaming matches the PyPI wheels; drop it for a lean local wheel
maturin build --release --features streaming
uv add --find-links target/wheels par-term-emu-core-rust
# or
pip install target/wheels/par_term_emu_core_rust-*.whl

Using as a Rust Library

The library can be used in pure Rust projects without Python. Choose your feature combination:

Note: Since v0.46.0 the pty_session module (real PTY backend) is a separate feature. Omit it only for headless use without PtySession. See docs/RUST_USAGE.md for details.

Download pre-built streaming server (recommended):

Pre-built binaries and web frontend packages are available from GitHub Releases:

# Download binary (Linux example)
wget https://github.com/paulrobello/par-term-emu-core-rust/releases/latest/download/par-term-streamer-linux-x86_64
chmod +x par-term-streamer-linux-x86_64

# Download web frontend (asset named par-term-web-frontend-v<version>.tar.gz from
# https://github.com/paulrobello/par-term-emu-core-rust/releases/latest)
mkdir -p ./web_term
tar -xzf par-term-web-frontend-v*.tar.gz -C ./web_term

# Run
./par-term-streamer-linux-x86_64 --web-root ./web_term

Available binaries: Linux (x86_64, ARM64), macOS (Intel, Apple Silicon), Windows (x86_64)

Or install from crates.io:

# Streaming server (no-default-features is required: the default python feature
# links libpython and fails at link time for a standalone binary)
cargo install par-term-emu-core-rust --no-default-features --features streaming-bin --bin par-term-streamer

# Terminal multiplexer daemon + client
cargo install par-term-emu-core-rust --no-default-features --features mux --bin par-mux

Or build from source:

cargo build --bin par-term-streamer --no-default-features --features streaming-bin --release
./target/release/par-term-streamer --help

See docs/RUST_USAGE.md for detailed Rust API documentation and examples.

Embedding in iOS Apps

The core ships a C API (src/ffi.rs, header include/terminal_core.h) for on-device embedding — the same emulator as par-term, packaged as a static xcframework for iOS device and simulator:

# Requires Xcode + rustup target add aarch64-apple-ios aarch64-apple-ios-sim
make xcframework
# → target/xcframework/TerminalCore.xcframework

TerminalCore.xcframework (device + simulator slices) is attached to GitHub releases starting with 0.56.0 — until then, build it locally with make xcframework. Each slice carries a Modules/module.modulemap, so after adding the xcframework to an Xcode project a Swift file just does import TerminalCore (the C header is re-exported; no bridging header needed).

The C surface is a full embedding API, not just snapshots:

• Lifecycle/input: terminal_create / terminal_free / terminal_feed (VT bytes) / terminal_resize
• Damage: terminal_dirty_ranges returns coalesced inclusive dirty-row ranges (the emulator knows exactly what changed) and terminal_mark_clean consumes them
• Pinned readback: terminal_read_row / terminal_read_scrollback_row copy cells into caller-owned buffers — no allocation, no full-grid copy per frame; terminal_get_cursor / terminal_get_modes carry per-frame state
• Key encoding: terminal_encode_key turns key events into PTY bytes (xterm legacy + kitty level-1 disambiguate, honoring application cursor keys and the negotiated kitty flags) so the frontend never reimplements key translation

Optional Components

Terminfo Installation

For optimal terminal compatibility, install the par-term terminfo definition:

# Install for current user
./terminfo/install.sh

# Or install system-wide
sudo ./terminfo/install.sh --system

# Then use
export TERM=par-term
export COLORTERM=truecolor

See terminfo/README.md for details.

Shell Integration

Enhances terminal with semantic prompt markers, command status tracking, and smart selection:

cd shell_integration
./install.sh  # Auto-detects bash/zsh/fish

See shell_integration/README.md for details.

Quick Start

Basic Terminal Emulation

from par_term_emu_core_rust import Terminal

# Create terminal
term = Terminal(80, 24)

# Process ANSI sequences
term.process_str("Hello, \x1b[31mWorld\x1b[0m!\n")
term.process_str("\x1b[1;32mBold green text\x1b[0m\n")

# Get content and cursor position
print(term.content())
col, row = term.cursor_position()
print(f"Cursor at: ({col}, {row})")

PTY (Interactive Shell)

from par_term_emu_core_rust import PtyTerminal

# Create PTY terminal and spawn shell
with PtyTerminal(80, 24) as term:
    term.spawn_shell()

    # Send commands
    term.write_str("echo 'Hello from shell!'\n")
    # Block until the output actually lands — no sleep guessing
    term.wait_for_text("Hello from shell!", timeout=3.0)

    # Get output
    print(term.content())

    # Resize terminal
    term.resize(100, 30)

    # Exit shell
    term.write_str("exit\n")
# Automatic cleanup

Environment Variables and Working Directory

Pass environment variables and working directory directly to spawn_shell() without modifying the parent process environment. This is safe for multi-threaded applications (e.g., Tokio):

from par_term_emu_core_rust import PtyTerminal

# Spawn with custom environment variables
with PtyTerminal(80, 24) as term:
    term.spawn_shell(env={"MY_VAR": "hello", "DEBUG": "1"})
    term.write_str("echo $MY_VAR\n")  # Outputs: hello

# Spawn with custom working directory
with PtyTerminal(80, 24) as term:
    term.spawn_shell(cwd="/tmp")
    term.write_str("pwd\n")  # Outputs: /tmp

# Combine both
with PtyTerminal(80, 24) as term:
    term.spawn_shell(env={"PROJECT": "myapp"}, cwd="/home/user/projects")

The spawn() method also accepts env and cwd parameters:

term.spawn("/bin/bash", ["-c", "echo $MY_VAR"], env={"MY_VAR": "test"}, cwd="/tmp")

Screenshots

term = Terminal(80, 24)
term.process_str("\x1b[1;31mHello, World!\x1b[0m\n")

# Save screenshot
term.screenshot_to_file("output.png")
term.screenshot_to_file("output.svg", format="svg")  # Vector graphics!
open("output.html", "w").write(term.export_html(include_styles=True))  # Styled HTML

# Custom configuration
term.screenshot_to_file(
    "output.png",
    font_size=16.0,
    padding=20,
    include_scrollback=True,
    minimum_contrast=0.5,  # iTerm2-compatible contrast adjustment
)

Color Utilities

from par_term_emu_core_rust import (
    perceived_brightness_rgb,
    adjust_contrast_rgb,
    contrast_ratio,
    meets_wcag_aa,
    rgb_to_hex,
    hex_to_rgb,
    mix_colors,
)

# iTerm2-compatible contrast adjustment
adjusted = adjust_contrast_rgb((64, 64, 64), (0, 0, 0), 0.5)

# WCAG accessibility checks
ratio = contrast_ratio((0, 0, 0), (255, 255, 255))
print(f"Contrast ratio: {ratio:.1f}:1")
print(f"Meets WCAG AA: {meets_wcag_aa((0, 0, 0), (255, 255, 255))}")

# Color conversions
hex_color = rgb_to_hex((255, 128, 64))  # "#FF8040"
rgb = hex_to_rgb("#FF8040")  # (255, 128, 64)
mixed = mix_colors((255, 0, 0), (0, 0, 255), 0.5)  # Purple

Macro Recording and Playback

from par_term_emu_core_rust import Macro, PtyTerminal
import time

# Create a macro manually
macro = Macro("git_status")
macro.set_description("Check git status and show branch")
macro.add_key("g")
macro.add_key("i")
macro.add_key("t")
macro.add_key("space")
macro.add_key("s")
macro.add_key("t")
macro.add_key("a")
macro.add_key("t")
macro.add_key("u")
macro.add_key("s")
macro.add_key("enter")
macro.add_delay(500)  # Wait 500ms
macro.add_screenshot("git_status.png")  # Trigger screenshot

# Save to YAML
macro.save_yaml("git_status.yaml")

# Load and play back
term = PtyTerminal(80, 24)
term.spawn_shell()

# Load macro from file
loaded_macro = Macro.load_yaml("git_status.yaml")
term.load_macro("git_check", loaded_macro)

# Play the macro
term.play_macro("git_check", speed=1.0)  # Normal speed

# Tick to execute macro events
while term.is_macro_playing():
    if term.tick_macro():  # Returns True if event was processed
        time.sleep(0.01)  # Small delay for visual effect

    # Check for screenshot triggers
    triggers = term.get_macro_screenshot_triggers()
    for label in triggers:
        term.screenshot_to_file(label)

# Convert a recording to a macro
term.start_recording("test session")
term.write_str("ls -la\n")
time.sleep(0.5)
session = term.stop_recording()

# Convert and save
macro = term.recording_to_macro(session, "ls_command")
macro.save_yaml("ls_command.yaml")

Examples

See the examples/ directory for comprehensive examples:

Basic Examples

• basic_usage_improved.py - Enhanced basic usage
• colors_demo.py - Color support
• cursor_movement.py - Cursor control
• text_attributes.py - Text styling
• unicode_emoji.py - Unicode/emoji support
• scrollback_demo.py - Scrollback buffer usage

Advanced Features

• alt_screen.py - Alternate screen buffer
• mouse_tracking.py - Mouse events
• bracketed_paste.py - Bracketed paste
• synchronized_updates.py - Flicker-free rendering
• shell_integration.py - OSC 133 integration
• test_osc52_clipboard.py - SSH clipboard
• test_kitty_keyboard.py - Kitty keyboard protocol
• hyperlink_demo.py - Clickable URLs
• notifications.py - Desktop notifications
• rectangle_operations.py - VT420 rectangle ops

Graphics and Export

• display_image_sixel.py - Sixel graphics
• test_sixel_simple.py - Simple sixel examples
• test_sixel_display.py - Advanced sixel display
• screenshot_demo.py - Screenshot features
• feature_showcase.py - Comprehensive TUI showcase

PTY Examples

• pty_basic.py - Basic PTY usage
• pty_shell.py - Interactive shells
• pty_resize.py - Dynamic resizing
• pty_event_loop.py - Event loop integration
• pty_mouse_events.py - Mouse in PTY
• pty_custom_env.py - Custom environment variables
• pty_multiple.py - Multiple PTY sessions
• pty_with_par_term.py - Integration with par-term

Terminal Streaming

• streaming_demo.py - Python WebSocket streaming server
• streaming_client.html - Browser-based terminal client

Macros and Automation

• demo.yaml - Example macro definition

Standalone Rust Server:

# Build and run (default: ws://127.0.0.1:8099)
make streamer-run

# Run with authentication
make streamer-run-auth

# Or use cargo directly
cargo build --bin par-term-streamer --no-default-features --features streaming-bin --release
./target/release/par-term-streamer --port 8099 --theme dracula

# With authentication
./target/release/par-term-streamer --api-key my-secret --theme monokai

# With system resource stats (CPU, memory, disk, network)
./target/release/par-term-streamer --enable-system-stats --system-stats-interval 5

# Install globally
make streamer-install
par-term-streamer --help

Available Themes: iterm2-dark, monokai, dracula, solarized-dark

Web Terminal Frontend

Using Pre-built Package (Recommended):

Download the pre-built static web frontend from GitHub Releases:

# Download and extract (asset named par-term-web-frontend-v<version>.tar.gz from
# https://github.com/paulrobello/par-term-emu-core-rust/releases/latest)
mkdir -p ./web_term
tar -xzf par-term-web-frontend-v*.tar.gz -C ./web_term

# Run streamer with web frontend
par-term-streamer --web-root ./web_term
# Open browser to http://localhost:8099

See web-terminal-frontend/README.md for detailed usage instructions.

Building from Source:

A modern Next.js-based web terminal frontend source is in web-terminal-frontend/:

cd web-terminal-frontend

# Install dependencies
npm install

# Development server (runs on port 8030)
npm run dev

# Build for production (outputs to out/)
npm run build

# Copy to web_term for serving
cp -r out/* ../web_term/

Features:

• Modern UI with Tailwind CSS v4
• xterm.js terminal emulator
• WebSocket connection to streaming server
• Theme selection and synchronization
• Responsive design
• Terminal resize support
• Customizable UI theme - Edit theme.css after build (no rebuild required)

See web-terminal-frontend/README.md for detailed setup and configuration.

TUI Demo Application

A full-featured TUI (Text User Interface) application is available in the sister project par-term-emu-tui-rust.

Installation: uv add par-term-emu-tui-rust or pip install par-term-emu-tui-rust

GitHub: https://github.com/paulrobello/par-term-emu-tui-rust

Technology

• Rust (1.98+) - Core library implementation
• Python (3.12+) - Python bindings
• PyO3 - Zero-cost Python/Rust bindings
• VTE - ANSI sequence parsing
• portable-pty - Cross-platform PTY support

Running Tests

# Run Rust tests
cargo test

# Run Python tests
uv sync  # Install dependencies including pytest
pytest tests/

Performance

• Zero-copy operations where possible
• Efficient grid representation
• Fast ANSI parsing with VTE crate
• Minimal Python/Rust boundary crossings

See docs/ARCHITECTURE.md for implementation details.

Security

When using PTY functionality, follow security best practices to prevent command injection and other vulnerabilities.

See docs/SECURITY.md for comprehensive security guidelines.

Contributing

Contributions are welcome! Please submit issues or pull requests on GitHub.

Development Setup

git clone https://github.com/paulrobello/par-term-emu-core-rust.git
cd par-term-emu-core-rust
make setup-venv  # Create virtual environment
make pre-commit-install  # Install pre-commit hooks (recommended)
make dev  # Build library
make checkall  # Run all quality checks

Code Quality

All contributions must pass:

• Rust formatting (cargo fmt)
• Rust linting (cargo clippy)
• Python formatting (make fmt-python)
• Python linting (make lint-python)
• Type checking (pyright)
• Tests (make test-python)

TIP: Use make pre-commit-install to automate all checks on every commit!

See CONTRIBUTING.md for the contribution workflow, and CLAUDE.md for detailed development instructions.

License

This project is licensed under the MIT License - see the LICENSE file for details.

Author

Paul Robello - probello@gmail.com

Links

• PyPI: https://pypi.org/project/par-term-emu-core-rust/
• Crates.io: https://crates.io/crates/par-term-emu-core-rust
• GitHub: https://github.com/paulrobello/par-term-emu-core-rust
• TUI Application: https://github.com/paulrobello/par-term-emu-tui-rust
• Documentation: See docs/ directory
• Examples: See examples/ directory