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.

Quick Install

Checksum-verified standalone binaries from the GitHub releases. Installs both the par-term-streamer streaming server and the par-mux multiplexer into ~/.cargo/bin (or $HOME\.cargo\bin).

macOS / Linux:

curl -fsSL https://raw.githubusercontent.com/paulrobello/par-term-emu-core-rust/main/install.sh | bash

Windows (PowerShell):

irm https://raw.githubusercontent.com/paulrobello/par-term-emu-core-rust/main/install.ps1 | iex

Options: --streamer / --streamer-mux / --mux (PowerShell: -Streamer / -StreamerMux / -Mux) install a subset, --version vX.Y.Z / -Version pins a release, and --bin-dir DIR / -BinDir picks a different destination. The default (no selectors) installs the plain streamer and par-mux; --mux combines with either streamer variant, --streamer and --streamer-mux are mutually exclusive.

What's New

Note: This section covers unreleased work on main and the last three releases. The complete release history is in CHANGELOG.md.

Version 0.72.0 adds per-pane human-presence stats, agent self-reporting, and restore policies for par-mux — pane-info and list-agents now carry viewer_count/last_viewed_at/last_input_at/cpu_ms so a supervisor can tell a human is driving; agents can park a pane's roster state themselves with report-state; per-agent last_activity_at/last_report_at/stalled and a replayable events ring give supervisors durable lifecycle events; new-session --restore start-command plus set-workspace-restore-policy (start-command/agent-resume/none) let a supervised pane re-run its original launch flags across restarts and give a workspace a hard no-restore opt-out; and a nested claude -p can no longer hijack its ancestor pane's agent claim (hook v4 + daemon guards + claim recovery). Breaking: the streamer now refuses legacy {SHA}/$1$/$apr1$ htpasswd hashes at startup by default — regenerate with htpasswd -nB, or pass --allow-legacy-hash. Also: a view re-land deletes the previous view's kitty graphics from the host; PtySession exports and screenshots render from snapshots instead of holding the terminal lock; a multi-pane-tab roster click survives a lagging %layout-change; and TerminalClipboard ships as a Python-side feature-scoped facade. See CHANGELOG.md for complete release notes.

Version 0.71.1 fixes the mirror streamer dying on a client text frame: the tungstenite transport serving par-term-streamer --mux-socket treated any TEXT frame as a protocol error and tore down the session, so a probing client's control text frame (pardeck sends one on every connect) killed an otherwise healthy mirror; the path now logs and skips text frames, matching the axum /ws route. See CHANGELOG.md for complete release notes.

Version 0.71.0 adds env-gated OpenTelemetry OTLP metrics for the streamer: with the new opt-in otel cargo feature compiled and --otel-enabled / PAR_TERM_STREAMER_OTEL_ENABLED set, par-term-streamer exports health series — connected clients, active sessions, event-send and protobuf-encode latency histograms, connections and reconnects, mux control-socket errors — to a collector (par-obs Grafana's future panel row); default builds carry no OpenTelemetry code and a feature build makes zero OTLP calls until enabled. Fixes ride along: the streamer's OTLP exporter reports export failures instead of failing silently and flushes on graceful shutdown; a side-panel agent-row click on a pane in another window lands focused on the clicked pane; a reconnecting attach no longer draws inside the dead session's stale scroll region; a workspace-active dial's Connected handshake reports the resolved pane id; and rebuilding Par-mux.app signs the bundle with the Developer ID identity so macOS TCC grants survive rebuilds. The dependency train bumps parking_lot to 0.13 (lock_api 0.5), unblocking par-term's workspace bump. See CHANGELOG.md for complete release notes.

Version 0.70.0 gives the mux named layouts: save-layout <name>, list-layouts, load-layout [-f] <name>, and kill-layout <name> capture the live pane tree into the daemon's layouts store and swap a stored tree back in place (-f required when live panes would be killed), and the attach TUI menu gains a layouts dialog (save with overwrite confirm, load with pick and confirm); a --state-dir daemon keeps its layouts beside its state file. The release also hardens the daemon's lifecycle: a second start on the same state file refuses after a handoff window (advisory flock — no more torn state files from racing daemons) and every exit logs its reason; --stop typed inside a pane refuses until --yes/--force so it can no longer kill the daemon hosting the caller's own shell; panes keep a spawn-cwd floor when neither OSC 7 nor the live cwd answers (agent TUIs no longer relaunch into $HOME after a crash-loop restore); a bare start hands off to the Par-mux.app launcher only when no daemon already serves (the follow-up attach no longer vanishes into the app's daemon.log); a --restart relaunch writes the shared daemon.log with hook debug lines; and the macOS launcher reads microphone status instead of requesting it (the TCC abort that killed pane-launched starts). Attach fixes ride along: a text drag ends at its release even under a full-pointer modal or over the side panel, resize-pane moves the pressed divider rather than the nearest ancestor's, the save/rename prompts accept shifted CSI-u characters, load-layout names a corrupt layout file instead of surfacing serde's encoding text, floored tab cells keep readable text when the strip overflows, and the Windows cross-target gate compiles again. See CHANGELOG.md for complete release notes.

Version 0.69.0 makes the mux mirror a first-class pane citizen and the gate fit the host: a late joiner replays a pane's graphics even when they were placed before the streamer attached (refresh-client -G carries the placements in the seed, and the mirror tags every frame with its pane), every graphics frame on the wire — inline_image and graphics_added — carries its source pane for the coming multi-pane clients, the attach TUI's wheel scrolls menus, dialogs, and pickers with the arrows' scroll-into-view behavior while pane scrollback keeps the wheel, and each workspace gains an exit action (remove/hold/shell) set live via set-exit-action — shell respawns the user's shell when a pane child exits (crash-loop guarded, inherited by agent-append resumed panes). The gate itself now splits by load tolerance: 219 tests are labeled load-sensitive and leave the default gate (run exactly that set with make test-rust-sensitive; checkall-ci keeps full coverage), so a loaded host can still gate load-insensitive changes. The dependency train moved to current stable across Cargo, uv, bun, and CI action pins. See CHANGELOG.md for complete release notes.

Version 0.68.0 makes files and images flow both ways across the mux, and the TUI points at what it means: a phone (or any streaming client) can push a file into a pane with four new control verbs (upload-begin/-chunk/-commit/-abort) — staging is bounded (64 KiB chunks, 100 MiB per upload, 8 concurrent, idle/total timeouts) and commit bracket-pastes the materialized file's path into the pane rather than injecting bytes into its input. The connect handshake's inline-image replay is bounded for phone-cellular budgets (newest frames first, stopping at 8 MiB aggregate / 24 frames, skipped tail logged), replayed frames carry their exact cell positions, and a late joiner's Connected now includes the frames already on screen. In the attach TUI, drag-cursor-shape is renamed change-cursor-shape and defaults ON (an explicit false in an existing config still wins; the old key is ignored), the pointer takes the pointing hand over clickable tabs, and the tab context menu opens under the clicked tab instead of mid-screen, clamped on-screen for far-right tabs. The async attach cleanup completes: the seed's and re-seed's status snapshots ride the pump's send_then continuation (no snapshot round trip parks the view), a push handled mid-seed stays out of the transition baseline (identical rebroadcasts toast again), and a gone-window landing resolves from the cached roster first. See CHANGELOG.md for complete release notes.

Version 0.65.0 makes the streamer and par-mux self-updating and one-line installable: both binaries gain --check-update/--self-update plus an opt-in auto mode that checks at startup and on an hourly/daily/weekly cadence (default daily), driven by one checksum-verified release engine (crates/par-term-emu-core/src/self_update.rs), and curl -fsSL .../install.sh | bash (PowerShell irm | iex twin) installs them into ~/.cargo/bin with streamer/mux/streamer-mux selectors. The release matrix now publishes a mux-enabled par-term-streamer-mux-<os>-<arch> artifact beside the plain streamer — each build self-updates only from its own artifact — and macOS release binaries are Developer ID signed and notarized, so the application firewall's allow rule survives update swaps. Mux-backed streaming viewers get pane_size_status (effective grid plus separate column/row constraint owners) and viewer_presence pushes, and a phone viewer's Fit resize no longer sticks after it disconnects: mux mirrors close on last-viewer disconnect, withdrawing the streamer's size claim so the remaining viewers re-fit the pane. See CHANGELOG.md for complete release notes.

Version 0.64.0 makes par-mux's sidebar show workspace state at a glance: every workspace row carries a herdr-style git badge ( main ↑2, ahead/behind counts, hidden for non-repos, detached HEAD, or [client] git-status = false) resolved daemon-side from the pane's OSC 7-tracked cwd on a 2-second bound with a TTL cache keyed to the new [client] git-poll-secs setting (0 disables polling), and the marker column shows each workspace's most urgent agent status glyph — question is a first-class agent state end to end (scrape-tier dialog rules, sounds, notifications, prompt verbs), outranking blocked. A new [daemon] split-start-dir setting (home-dir | previous-pane-dir | workspace-dir) picks the folder a split-window pane starts in when no -c is given, and a new [daemon.agent-append] table carries per-agent resume words that agent-start appends when it launches one of the fourteen supported agents ({name} expands to the pane cwd's basename and every word is shell-quoted, so a configured value can never execute shell syntax). The streaming agent-roster entries gain workspace, project, and pane_label fields populated end to end (pane-title query, probe attribution), so ParDeck's phone roster can render them, and a restored daemon re-seeds its agents' last-known state so list-agents survives a restart. Seven fixes ride along: ED2/ED3 full-screen erases clear soft-wrap metadata so erased rows no longer stay joined in content() and par-mux capture-pane; kind-filtered event observers can subscribe to pointer_shape_changed again (the TerminalEventKind::ALL table had dropped it); the pane-stream seed's race check now samples its baseline before the export; bulk --install-agent-hooks covers all twelve hook arms (qwen, qodercli, devin, kimi, and mastracode were missing); the workspace status glyph sits next to the workspace name instead of displacing the marker column; a streaming session close no longer panics when the drain thread runs off the Tokio runtime; and reload-config re-reads the applied copy's stamped config path. See CHANGELOG.md for complete release notes.

Version 0.63.0 makes par-mux self-updating and extensible: par-mux update [--channel stable|preview] downloads the platform archive from GitHub releases, verifies the new binary's --version before replacing anything, keeps par-mux.previous beside it, and restarts the daemon through the stop-and-restore handoff; a checksum-verified curl|sh installer and a Homebrew tap template join it. The release also ships a trust-gated plugin system (manifests, event hooks), saved machines and an SSH thin client, persistence resilience (snapshot history, logind shutdown inhibitor), a macOS app-bundle wrapper for TCC permissions with launchd autostart, and a large attach batch — an interactive session picker, kitty graphics rendered in panes, popup command windows, theme presets with auto light/dark switching, IME/CJK input, drag-to-highlight copy, and jump-to-notification. Daemon side: git worktree workspaces, the done agent state, agent-start/agent-prompt/agent-explain/wait-output/show-notification control commands, raw pane streams for local clients, shell completions, and herdr's agent-integration ports. Breaking for configs that set notify-states explicitly: [client] notify-states now defaults to ["blocked", "done"], so add "done" to keep hearing about background finishes. See CHANGELOG.md for complete release notes.

Every other release is documented in CHANGELOG.md.

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 (ptec_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
• Attach Client - par-mux attach renders sessions in your terminal (render mode, the default) or byte-pumps one pane (passthrough), with workspaces, a sidebar, and a config file; see docs/MUX.md
• Crash-Safe State - Atomic saves with quarantine of unreadable state files; a clean SIGTERM never loses the last window

Standalone Binary Updates

Both par-term-streamer and par-mux support --check-update (report only) and --self-update (install and restart). Updates use this repository's GitHub releases, require SHA-256 checksum sidecars, and retain a .previous binary beside the installation. Automatic installation is off by default. Enable streamer --auto-update or mux [daemon] auto-update = true, with an hourly, daily (default), or weekly interval. See streamer configuration and mux configuration for restart behavior and the app-bundle guard.

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
• Troubleshooting - Common build, test, streaming, and par-mux failures in one place
• Configuration Reference - Configuration options and the environment variable reference
• 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
• Manual Pass Checklist - Human pass over the par-mux attach client in real terminal emulators (the attach ship gate)
• 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
• Benchmarking - Criterion throughput benches and interleaved A/B comparison
• Testing Kitty Animations - Testing Kitty graphics animation support
• Regional Flag Limitation - Why regional-indicator flag emoji may not render as one glyph in some frontends
• Maturin Best Practices - Wheel build and packaging compliance review
• par-mux Design Pointer - Where the par-mux design plan lives
• par-mux Design Decisions - One-line summaries of the D-numbered decisions cited in code
• Documentation Style Guide - Standards for writing project documentation

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 1.99+ and Python 3.12+:

# Install maturin (build tool)
uv tool install maturin

# Build and install
maturin develop --release

Building a Wheel

# streaming is included: pyproject.toml [tool.maturin] features apply to every maturin build
maturin build --release
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)

Pre-built par-mux daemon binaries (standalone: no Python, no par-term installation) are attached to the same GitHub Releases as par-mux-v<version>-<target>.tar.gz (Unix) / .zip (Windows) archives with a SHA256SUMS file. Per-platform install steps: docs/MUX.md.

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 with the attach client (the standalone par-mux crate):
cargo install par-mux --features mux-bin,attach

Or build them from a source checkout (drop ,attach for the daemon alone):

cargo install --path crates/par-mux --features mux-bin,attach --locked

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 from 0.56.0 on; build it locally with make xcframework for unreleased commits. 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 (contracts and examples in the FFI Guide):

• Version check: ptec_terminal_abi_version — compare against the header's TERM_CORE_ABI_VERSION at startup
• Lifecycle/input: ptec_terminal_create / ptec_terminal_free / ptec_terminal_feed (VT bytes) / ptec_terminal_resize
• Damage: ptec_terminal_dirty_ranges returns coalesced inclusive dirty-row ranges and ptec_terminal_mark_clean consumes them; independent renderers use ptec_terminal_damage_generation + ptec_terminal_dirty_ranges_since, so one consumer never hides damage from another
• Scroll-aware damage (ABI v5): ptec_terminal_scroll_delta_since + ptec_terminal_content_dirty_ranges_since report a region's net scroll plus only the content-changed rows, so a renderer blits on scroll and redraws just the new rows
• Pinned readback: ptec_terminal_read_row / ptec_terminal_read_scrollback_row / ptec_terminal_scrollback_count copy cells into caller-owned buffers — no allocation, no full-grid copy per frame — with palette-resolved colors and default-color bits (ABI v4); ptec_terminal_read_cell_grapheme returns a cell's full grapheme cluster; ptec_terminal_scrollback_total_scrolled pairs with the count to sync a mirrored scrollback window; ptec_terminal_get_cursor / ptec_terminal_get_modes carry per-frame state
• Key encoding: ptec_terminal_encode_key turns key events into PTY bytes (xterm legacy, kitty level-1 disambiguate, and modifyOtherKeys, honoring application cursor keys and the negotiated kitty flags); ptec_terminal_encode_key_ex adds per-side macOS Option-key modes through TermKeyOptions
• Snapshots and observers: ptec_terminal_get_state / ptec_terminal_free_state, ptec_terminal_add_observer / ptec_terminal_remove_observer; the on_event_v2 slot delivers structured TermEvents (a TERM_EVENT_* kind plus a JSON payload)

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

Diagnostics and Test Scripts

• bce_scroll_test.py - Background color erase (BCE) during scrolling
• char_test.py - Character-specific rendering test
• gradient_test.py - Minimal gradient test for terminal wrap behavior
• rich_mimic_test.py - Rich-style output rendering test
• scroll_timing_test.py - Scroll timing test
• streaming_debug.py - Streaming server debug tool
• test_tui_clipboard.py - TUI clipboard and selection features
• test_underline_styles.py - Underline styles (SGR 4:x)
• render_utils.py - Rendering helpers imported by the other examples (not run directly)

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/:

# Install dependencies (bun)
make web-install

# Development server on http://localhost:3000
make web-dev

# Static build copied to web_term/ for par-term-streamer --web-root
make web-build-static

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 (1.99+) - 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

# All tests: Rust, Rust streaming, and Python (rebuilds the extension first)
make test

# Rust tests only (plain `cargo test` fails to link under the default `python` feature)
make test-rust

# Python tests only (runs `make dev` first)
make test-python

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!

Load-Sensitive Tests

Timing-dependent Rust tests (the PTY and attach integration suites, and render tests pinned to timing) are labeled #[ignore = "load-sensitive ..."]. A plain cargo test and make checkall skip them, and make test-rust prints how many it deferred. Run them as follows:

• make test-rust-sensitive runs exactly the labeled set.
• make checkall-ci includes them (its nextest legs run ignored tests too), so it is the gate to pass before pushing a change that touches a labeled test.
• To run one suite by hand, pass --include-ignored, for example cargo test -p par-mux --features mux-bin,attach --test mux_attach -- --include-ignored --test-threads=1.

These tests measure wall-clock behavior, so run them on a quiet machine. Under heavy host load a failure is usually a timing flake rather than a regression, so re-run on an idle host before debugging.

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