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
Version 0.41.0 adds TriggerAction::SplitPane — a new trigger action that instructs frontends to open a split pane with configurable direction (horizontal/vertical), focus behaviour, target pane, and an optional command (SendText or InitialCommand). Poll results via poll_action_results() which returns dicts with type="split_pane". See CHANGELOG.md for complete release notes.
What's New in 0.40.0
Version 0.40.0 added full VT100 ACS (Alternate Character Set) line-drawing support. Applications like tmux that fall back from UTF-8 to ACS now render correct box-drawing glyphs (┌, ┐, └, ┘, ─, │, ┼, etc.) instead of raw ASCII letters.
What's New in 0.34.0
OSC 1337 RemoteHost Support
Parse OSC 1337 ; RemoteHost=user@hostname ST sequences for remote host detection. This is iTerm2's dedicated mechanism for reporting remote host information, commonly emitted by shell integration scripts on remote hosts. The ShellIntegration state now includes hostname and username attributes, and a cwd_changed event is emitted when the remote host changes.
# After SSH to a remote host with iTerm2 shell integration:
# The shell sends: printf '\e]1337;RemoteHost=%s@%s\a' "$USER" "$HOSTNAME"
=
# "remote-server.example.com"
# "alice"
🔤 Unicode Normalization (NFC/NFD/NFKC/NFKD)
Configurable Unicode normalization ensures consistent text storage for search, comparison, and cursor movement. Unicode characters can have multiple binary representations that look identical (e.g., é can be precomposed U+00E9 or decomposed U+0065 + U+0301). Normalization eliminates this ambiguity.
=
# Default is NFC (Canonical Composition) - most common form
assert ==
# Switch to NFD (Canonical Decomposition) for macOS HFS+ compatibility
# NFKC replaces compatibility characters (e.g., fi ligature → fi)
# Disable normalization entirely
Normalization Forms:
NormalizationForm.NFC- Canonical Composition (default): composese+ combining accent →éNormalizationForm.NFD- Canonical Decomposition: decomposesé→e+ combining accentNormalizationForm.NFKC- Compatibility Composition: NFC + replaces compatibility chars (fi→fi)NormalizationForm.NFKD- Compatibility Decomposition: NFD + replaces compatibility charsNormalizationForm.Disabled- No normalization, store text as received
OSC 1337 SetUserVar Support
Shell integration scripts can now send user variables via OSC 1337 SetUserVar=<name>=<base64_value> sequences. Variables are base64-decoded, stored on the terminal, and accessible via a dedicated API. A UserVarChanged event is emitted when values change, enabling features like remote host detection, automatic profile switching, and hostname display.
# After shell sends: printf '\e]1337;SetUserVar=%s=%s\a' "hostname" "$(printf 'server1' | base64)"
= # "server1"
= # {"hostname": "server1", ...}
# Event-driven: poll for changes
Image Metadata Serialization for Session Persistence
Graphics state can now be serialized and restored for session persistence. All active placements, scrollback graphics, and animation state are captured in a versioned JSON snapshot with base64-encoded pixel data. External file references are also supported for compact on-disk storage.
# Save graphics state
=
# Restore graphics state in a new session
=
Image Placement Metadata
All graphics protocols now expose unified ImagePlacement metadata on Graphic.placement, abstracting protocol-specific placement parameters so frontends can implement inline/cover/contain rendering. The Kitty protocol exposes columns/rows sizing, z-index for layering, and sub-cell offsets. The iTerm2 protocol exposes width/height with unit support (cells, pixels, percent, auto) and preserveAspectRatio. New ImagePlacement and ImageDimension classes are importable from the package.
Original Image Dimensions for Aspect Ratio Preservation
All graphics protocols (Sixel, iTerm2, Kitty) now expose original_width and original_height on Graphic objects. These fields preserve the original decoded pixel dimensions even when width/height change during animation, enabling frontends to calculate correct aspect ratios when scaling images to fit terminal cells.
Kitty Graphics Compression Support
The Kitty graphics protocol now supports zlib-compressed image payloads (o=z parameter). Compressed data is automatically decompressed before pixel decoding, reducing data sent over the PTY. A new was_compressed flag on the Graphic class allows frontends to track compression usage for diagnostics.
Dependencies
- Migrated to PyO3 0.28 from 0.23, updating all Python binding patterns to the latest API
flate2is now a non-optional dependency (required for Kittyo=zdecompression)- Added
unicode-normalizationv0.1.25 for Unicode text normalization support
What's New in 0.33.0
Multi-Session Streaming Server
The streaming server now supports multiple concurrent terminal sessions. Each WebSocket client can connect to a named session, and new sessions are created on demand:
ws://host:port/ws?session=my-session # Connect to (or create) a named session
ws://host:port/ws?preset=python # Create a session using a shell preset
ws://host:port/ws # Connect to the default session
Key features:
- Session isolation: Each session has its own terminal, PTY, and broadcast channels
- Shell presets: Define named shell commands (
--preset python=python3 --preset node=node) - Idle timeout: Sessions with no clients are automatically reaped (default: 15 minutes)
- Client identity: Each client receives a unique
client_idin the Connected handshake - Read-only awareness: The
readonlyfield in Connected tells clients their permission level
Default limits:
- Max concurrent sessions: 10
- Idle session timeout: 900 seconds (15 minutes)
- Max clients per server: 100 (unchanged)
New Streaming Events: Mode, Graphics, and Hyperlink
Three new event types allow streaming clients to react to terminal state changes:
- ModeChanged: Fires when terminal modes toggle (e.g., cursor visibility, mouse tracking, bracketed paste). Subscribe with
"mode". - GraphicsAdded: Fires when images are rendered via Sixel, iTerm2, or Kitty protocols. Includes row position and format. Subscribe with
"graphics". - HyperlinkAdded: Fires when OSC 8 hyperlinks are added. Includes URL, row, column, and optional link ID. Subscribe with
"hyperlink".
Breaking: StreamingConfig has new required fields (max_sessions, session_idle_timeout, presets). ServerMessage::Connected now includes client_id and readonly fields.
What's New in 0.32.0
Coprocess Restart Policies & Stderr Capture
Coprocesses now support automatic restart when they exit, and stderr is captured separately:
# Start a coprocess that auto-restarts on failure with a 1-second delay
=
=
# Read stderr separately from stdout
=
=
Restart Policies: "never" (default), "always", "on_failure" (non-zero exit only)
Trigger Notify & MarkLine as Frontend Events
Notify and MarkLine trigger actions now emit ActionResult events (via poll_action_results()) instead of directly modifying internal state. This gives frontends full control over how notifications and line marks are displayed. MarkLine also supports an optional color parameter:
=
Breaking: If you relied on Notify triggers adding to the notification queue or MarkLine triggers adding bookmarks directly, you must now handle these via poll_action_results().
What's New in 0.31.1
Trigger Column Mapping Fix
TriggerMatch.col and TriggerMatch.end_col now correctly report grid column positions for text containing wide characters (CJK, emoji) and multi-byte UTF-8 characters. Previously, regex byte offsets were used directly, producing incorrect column values for non-ASCII text. Trigger highlights now correctly overlay the matched text even when wide or combining characters appear in the same row.
What's New in 0.31.0
Triggers & Automation
Register regex patterns to automatically match terminal output and execute actions — highlight matches, send notifications, set bookmarks, update session variables, or emit events for frontend handling:
=
# Highlight errors in red
=
# Set a session variable from matched output
=
# Process terminal output and scan for matches
# Poll results
= # TriggerMatch objects with captures
= # Active highlight overlays
Trigger Actions: highlight, notify, mark_line, set_variable, run_command, play_sound, send_text, stop
Features:
RegexSet-based multi-pattern matching for efficient scanning- Capture group substitution (
$1,$2) in action parameters - Highlight overlays with optional time-based expiry
- Automatic scanning in PTY mode; manual
process_trigger_scans()for non-PTY
Coprocess Management
Run external processes alongside terminal sessions with automatic output piping:
# Start a coprocess that receives terminal output
=
=
# Read coprocess output
=
# Check status and stop
# True if running
New Python Classes: Trigger, TriggerAction, TriggerMatch, CoprocessConfig
What's New in 0.30.0
⌨️ modifyOtherKeys Protocol Support
XTerm extension for enhanced keyboard input reporting, enabling applications to receive modifier keys with regular characters:
=
# Enable modifyOtherKeys mode via escape sequence
# Mode 2: report all keys with modifiers
# Output: 2
# Or set directly
# Mode 1: special keys only
# Query mode (response in drain_responses())
= # Returns b"\x1b[>4;1m"
Modes:
0- Disabled (default)1- Report modifiers for special keys only2- Report modifiers for all keys
New Methods:
modify_other_keys_mode()- Get current modeset_modify_other_keys_mode(mode)- Set mode directly (values > 2 clamped to 2)
Sequences:
CSI > 4 ; mode m- Set modeCSI ? 4 m- Query mode (response:CSI > 4 ; mode m)
Note: Mode resets to 0 on terminal reset and when exiting alternate screen.
🎨 Faint Text Alpha Control
Configurable alpha multiplier for SGR 2 (dim/faint) text, allowing fine-grained control over how dim text is rendered:
=
# Get current faint text alpha (default: 0.5 = 50% dimming)
# Output: 0.5
# Set faint text to be more transparent (more dimmed)
# 30% opacity
# Set faint text to be less transparent (less dimmed)
# 70% opacity
# Values are clamped to 0.0-1.0 range
# Clamped to 1.0
# Clamped to 0.0
New Methods:
faint_text_alpha()- Get current alpha multiplier (0.0-1.0)set_faint_text_alpha(alpha)- Set alpha multiplier (clamped to valid range)
Usage: This setting is used by the screenshot renderer and can be queried by frontends for consistent rendering of dim text (SGR 2).
What's New in 0.28.0
🏷️ Badge Format Support (OSC 1337 SetBadgeFormat)
iTerm2-style badge support for terminal overlays with variable interpolation:
=
# Set badge format with variables
# Set session variables
# Evaluate badge - returns "alice@server1"
=
# Get all session variables
=
New Methods:
badge_format()- Get current badge format templateset_badge_format(format)- Set badge format with\(variable)placeholdersclear_badge_format()- Clear badge formatevaluate_badge()- Evaluate badge with session variablesget_badge_session_variable(name)- Get a session variable valueset_badge_session_variable(name, value)- Set a custom session variableget_badge_session_variables()- Get all session variables as a dictionary
Built-in Variables:
hostname, username, path, job, last_command, profile_name, tty, columns, rows, bell_count, selection, tmux_pane_title, session_name, title
Security: Badge formats are validated to reject shell injection patterns (backticks, $(), pipes, etc.)
🔧 Tmux Control Mode Fixes
- Fixed CRLF line ending handling (strips
\rfrom\r\nline endings) - Fixed
%outputnotifications to preserve trailing spaces - Fixed OSC 133 exit code parsing from
OSC 133 ; D ; <exit_code> ST
What's New in 0.27.0
🔄 Tmux Control Mode Auto-Detection
Automatic detection and switching to tmux control mode to handle race conditions:
=
# Enable auto-detection before starting tmux
# Parser will automatically switch to control mode when %begin is seen
# Or just call set_tmux_control_mode(True) which enables auto-detect automatically
# Process tmux output - auto-detects %begin and switches modes
# Check modes
New Methods:
set_tmux_auto_detect(enabled)- Enable/disable auto-detection of tmux control modeis_tmux_auto_detect()- Check if auto-detection is enabled
Behavior:
- When
%beginnotification is detected, parser automatically switches to control mode - Data before
%beginis returned asTerminalOutputnotification for normal display - Calling
set_tmux_control_mode(True)now also enables auto-detect
What's New in 0.26.0
🎬 Session Recording Enhancements
Full Python API for session recording with event iteration and environment capture:
=
# Start recording
=
# Access session metadata
# Iterate over recorded events
New Exports:
RecordingEventandRecordingSessionnow directly importable from the module
New RecordingSession Properties:
session.events- List of RecordingEvent objectssession.env- Dict of captured environment variables
New PtyTerminal Methods:
record_output(),record_input(),record_resize(),record_marker(),get_recording_session()
What's New in 0.25.0
🌐 Configurable Unicode Width
Full control over character width calculations for proper terminal alignment in CJK and mixed-script environments:
# Configure terminal for CJK environment (Greek/Cyrillic = 2 cells)
=
# Or configure individually
# Standalone width functions
# 2 - CJK character
# 2 - Greek with CJK config
# 9 - mixed text
# True - Greek is ambiguous
New Types:
UnicodeVersion: Unicode9-Unicode16, AutoAmbiguousWidth: Narrow (1 cell), Wide (2 cells)WidthConfig: Combines both with.cjk()and.western()presets
New Functions:
char_width(c, config?)/str_width(s, config?)- configurable widthchar_width_cjk(c)/str_width_cjk(s)- CJK convenience functionsis_east_asian_ambiguous(c)- check if character is ambiguous
What's New in 0.23.0
📨 Configurable ENQ Answerback
- Added an optional answerback string that the terminal returns when receiving ENQ (0x05)
- Disabled by default for security; set a custom value via Rust API or Python bindings
- Responses are buffered in the existing response buffer and drained with
drain_responses() - Python bindings now expose
answerback_string()andset_answerback_string()
What's New in 0.22.1
🐛 Search Unicode Bug Fix
Fixed search() and search_scrollback() returning byte offsets instead of character offsets for text containing multi-byte Unicode characters (CJK, emoji, etc.):
SearchMatch.colnow correctly returns the character column positionSearchMatch.lengthnow correctly returns the character count- Example: Searching for "World" in "こんにちは World" now returns
col=6(correct) instead ofcol=16(byte offset)
What's New in 0.22.0
🏳️ Regional Indicator Flag Emoji Support
Proper grapheme cluster handling for flag emoji like 🇺🇸, 🇬🇧, 🇯🇵:
- Flag emoji are now correctly combined into single wide (2-cell) graphemes
- Two regional indicator codepoints are combined with the first as the base character and the second in the combining vector
- Cursor correctly advances by 2 cells after writing a flag
- Added
unicode-segmentationcrate dependency for grapheme cluster support - Comprehensive test suite for flag emoji
What's New in 0.21.0
🚀 parking_lot Migration
The entire library has been migrated from std::sync::Mutex to parking_lot::Mutex.
- Improved Reliability: Eliminated "Mutex Poisoning". A panic in one thread no longer renders the terminal state permanently inaccessible to other threads.
- Better Performance: Faster lock/unlock operations and significantly smaller memory footprint for locks.
- Ergonomic API: Lock acquisition no longer requires
.unwrap(), making the code cleaner and more robust.
What's New in 0.20.1
🔧 Safe Environment Variable API
Added new methods to pass environment variables and working directory directly to spawned processes without modifying the global environment of the parent process.
- Rust:
spawn_shell_with_env(env, cwd),spawn_with_env(command, args, env, cwd) - Python:
spawn_shell(env=None, cwd=None)- now supports optional environment dictionary and working directory path. - Thread Safety: Eliminates the need for
unsafe { std::env::set_var() }in multi-threaded applications like those using Tokio.
What's New in 0.20.0
🎨 External UI Theme
The web frontend UI chrome can now be customized after static build without rebuilding:
/* Edit web_term/theme.css */
}
- Edit colors and refresh the page - no rebuild required
- Terminal emulator colors (ANSI palette) still controlled by server
--themeoption - See docs/STREAMING.md for details
🐛 Bug Fixes
- Web Terminal On-Screen Keyboard: Fixed native device keyboard appearing when tapping on-screen keyboard buttons on mobile devices
- The on-screen keyboard now properly prevents xterm's internal textarea from gaining focus
- Tapping virtual keys no longer triggers the device's native keyboard
What's New in 0.19.5
🐛 Bug Fixes
- Streaming Server Shell Restart Input: Fixed WebSocket client connections not receiving input after shell restart
- PTY writer was captured once at connection time, becoming stale after shell restart
- Client keyboard input now properly reaches the shell after any restart
What's New in 0.19.4
🔧 Python SDK Sync
- Python SDK aligned with Rust SDK: All streaming features now available in Python bindings
StreamingConfig.enable_http/web_root- HTTP server configuration (getter/setter)StreamingServer.max_clients()- Query maximum allowed clientsStreamingServer.create_theme_info()- Create theme dictionaries for protocolencode_server_message("pong")- Pong message encoding supportencode_server_message("connected", theme=...)- Theme support in connected messages
# Configure HTTP serving
=
# Create theme for connected message
=
# Encode messages
=
=
What's New in 0.19.2
🐛 Bug Fixes
- Streaming Server Hang on Shell Exit: Fixed server hanging indefinitely when the shell exits
- Added shutdown signal mechanism to gracefully terminate the broadcaster loop
- Prevents blocking indefinitely when shell exits in some conditions
What's New in 0.19.1
🐛 Bug Fixes
- Streaming Server Ping/Pong: Fixed application-level ping/pong handling
- Server was sending WebSocket-level pong frames instead of protobuf
Pongmessages - Frontend heartbeat mechanism now properly receives pong responses
- Fixes stale connection detection that was failing due to missing pong responses
- Server was sending WebSocket-level pong frames instead of protobuf
What's New in 0.19.0
🎉 New Features
-
Automatic Shell Restart: Streaming server now automatically restarts the shell when it exits
- Default behavior: shell is restarted automatically when it exits
- New
--no-restart-shellCLI option to disable automatic restart - New
PAR_TERM_NO_RESTART_SHELLenvironment variable support - When restart is disabled, server exits gracefully when the shell exits
-
Header/Footer Toggle in On-Screen Keyboard: Layout toggle button in keyboard header
- Show/hide header and footer directly from the on-screen keyboard
- Blue indicator shows when header/footer is visible
- Convenient for maximizing terminal space on mobile
-
Font Size Controls in On-Screen Keyboard: Plus/minus buttons in keyboard header
- Adjust font size (8-32px) without opening the header panel
🔧 Changes
- StreamingServer API:
set_pty_writernow uses interior mutability for shell restart support - UI Improvements: Font size controls moved to keyboard header; floating buttons repositioned side by side
What's New in 0.18.2
🎉 New Features
-
Font Size Control: User-adjustable terminal font size in web frontend
- Plus/minus buttons in header (8px to 32px range)
- Persisted to localStorage across sessions
-
Heartbeat/Ping Mechanism: Stale WebSocket connection detection
- Sends ping every 25s, expects pong within 10s
- Automatically closes and reconnects stale connections
🔒 Security Hardening
- Web Terminal Security Fixes: Comprehensive security audit remediation
- Reverse-tabnabbing prevention: Terminal links now open with
noopener,noreferrer - Zip bomb protection: Added decompression size limits (256KB compressed, 2MB decompressed)
- Localhost probe fix: WebSocket preconnect hints gated to development mode only
- Snapshot size guard: 1MB limit on screen snapshots to prevent UI freezes
- Reverse-tabnabbing prevention: Terminal links now open with
🐛 Bug Fixes
- WebSocket URL Changes: Properly disconnects and reconnects when URL changes
- Invalid URL Handling: Displays friendly error instead of crashing
- Next.js Config: Merged duplicate config files into single file
- Toggle Button Overlap: Moved button left to avoid scrollbar overlap
What's New in 0.18.1
🐛 Bug Fixes
- Web Terminal On-Screen Keyboard: Fixed device virtual keyboard appearing when tapping on-screen keyboard buttons on mobile devices
- Added
tabIndex={-1}to all buttons to prevent focus acquisition that triggered device keyboard
- Added
What's New in 0.18.0
🎉 New Features
-
Environment Variable Support: All CLI options now support environment variables with
PAR_TERM_prefix- Examples:
PAR_TERM_HOST,PAR_TERM_PORT,PAR_TERM_THEME,PAR_TERM_HTTP_USER - Configuration via environment for containerized deployments
- Examples:
-
HTTP Basic Authentication: New password protection for the web frontend
--http-user- Username for HTTP Basic Auth--http-password- Clear text password--http-password-hash- htpasswd format hash (bcrypt, apr1, SHA1, MD5 crypt)--http-password-file- Read password from file (auto-detects hash vs clear text)
🧪 Test Coverage
- Comprehensive Streaming Test Suite: 94 new tests for streaming functionality
- Protocol message constructors, theme info, HTTP Basic Auth configuration
- Binary protocol encoding/decoding with compression
- Event types, streaming errors, JSON serialization
- Unicode content and ANSI escape sequence preservation
🔧 Improvements
- Python Bindings: Binary protocol functions now properly exported (
encode_server_message,decode_server_message,encode_client_message,decode_client_message)
Usage Examples
# Environment variables
# CLI with htpasswd hash
What's New in 0.17.0
🎉 New Features
-
Web Terminal Macro System: New macro tab in the on-screen keyboard for creating and playing terminal command macros
- Create named macros with multi-line scripts (one command per line)
- Quick select buttons to run macros with a single tap
- Playback with 200ms delay before each Enter key for reliable command execution
- Edit and delete existing macros via hover menu
- Stop button to abort macro playback mid-execution
- Macros persist to localStorage across sessions
- Visual feedback during playback (pulsing animation, stop button)
- Option to disable sending Enter after each line (for text insertion macros)
- Template commands for advanced scripting:
[[delay:N]],[[enter]],[[tab]],[[esc]],[[space]],[[ctrl+X]],[[shift+X]],[[ctrl+shift+X]],[[shift+tab]],[[shift+enter]]
-
On-Screen Keyboard Enhancements:
- Permanent symbols grid on the right side with all keyboard symbols (32 keys)
- Added Space, Enter, http://, and https:// buttons to modifier row
- Added tooltips to Ctrl shortcut buttons
- Expanded symbol keys with full punctuation set
🔧 Improvements
- On-Screen Keyboard Layout: Reorganized for better usability with more compact vertical layout and persistent symbols grid
📦 Dependency Updates
- Web Frontend: Updated @types/node (25.0.1 → 25.0.2)
What's New in 0.16.3
🐛 Bug Fixes
- Web Terminal tmux/TUI Fix: Fixed control characters (
^[[?1;2c^[[>0;276;0c) appearing when running tmux or other TUI applications in the web terminal. The issue was caused by xterm.js generating Device Attributes responses when the backend terminal emulator already handles these queries.
🚀 Performance Optimizations
- jemalloc Allocator: New optional
jemallocfeature for 5-15% server throughput improvement (non-Windows only) - TCP_NODELAY: Disabled Nagle's algorithm for lower keystroke latency (up to 40ms improvement)
- Output Batching: Time-based batching at 60fps reduces WebSocket overhead by 50-80% during burst output
- Compression Threshold: Lowered to 256 bytes to compress more typical terminal output
- WebSocket Preconnect: Reduces initial connection latency by 100-200ms
- Font Preloading: Eliminates layout shift and font flash
📦 Dependency Updates
- Web Frontend: Updated Next.js and type definitions
- Pre-commit Hooks: Updated ruff linter
What's New in 0.16.2
🔧 Compatibility Fix
- TERM Environment Variable: Changed default
TERMfromxterm-kittytoxterm-256colorfor better compatibility with systems lacking kitty terminfo
What's New in 0.16.0
🔒 TLS/SSL Support
- Secure WebSocket Connections for production deployments:
- New CLI options:
--tls-cert,--tls-key,--tls-pem - Supports separate cert/key files or combined PEM
- Enables HTTPS and WSS (secure WebSocket)
- New CLI options:
# Using separate cert and key files
# Using combined PEM file
🚀 Performance: Binary Protocol
- BREAKING: Protocol Buffers for WebSocket Streaming:
- Replaced JSON with binary Protocol Buffers encoding
- ~80% smaller messages for typical terminal output
- Optional zlib compression for large payloads (screen snapshots)
- Wire format: 1-byte header + protobuf payload
🐍 Python Bindings
- TLS Configuration:
StreamingConfigmethods for TLS setup - Binary Protocol Functions:
encode_server_message(),decode_server_message(),encode_client_message(),decode_client_message()
See CHANGELOG.md for complete version history.
What's New in 0.15.0
🎉 New Features
- Streaming Server CLI Enhancements:
--download-frontendoption to download prebuilt web frontend from GitHub releases--frontend-versionoption to specify version to download (default: "latest")--use-tty-sizeoption to use current terminal size from TTY- No longer requires Node.js/npm to use web frontend - can download prebuilt version
Quick Start
# Build the streaming server
# Download prebuilt web frontend (no Node.js required!)
# Run server with frontend
# Open browser to http://127.0.0.1:8099
What's New in 0.14.0
🎉 New Features
-
Web Terminal Onscreen Keyboard: Mobile-friendly virtual keyboard for touch devices
- Special keys missing from iOS/Android keyboards: Esc, Tab, arrow keys, Page Up/Down, Home, End, Insert, Delete
- Function keys F1-F12 (toggleable), symbol keys (|, , `, ~, {, }, etc.)
- Modifier keys (Ctrl, Alt, Shift) that combine with other keys
- Quick Ctrl shortcuts: ^C, ^D, ^Z, ^L, ^A, ^E, ^K, ^U, ^W, ^R
- Glass morphism design, haptic feedback, auto-shows on mobile
-
OSC 9;4 Progress Bar Support (ConEmu/Windows Terminal style):
- Terminal applications can report progress that can be displayed in tab bars, taskbars, or window titles
What's New in 0.13.0
🎉 New Features
-
Streaming Server Enhancements:
--sizeCLI option for specifying terminal size inCOLSxROWSformat (e.g.,--size 120x40or-s 120x40)--command/-cCLI option to execute a command after shell startup (with 1 second delay for prompt settling)initial_colsandinitial_rowsconfiguration options inStreamingConfigfor both Rust and Python APIs
-
Python Bindings Enhancements:
- New
MouseEncodingenum for mouse event encoding control (Default, Utf8, Sgr, Urxvt) - Direct screen buffer control:
use_alt_screen(),use_primary_screen() - Mouse encoding control:
mouse_encoding(),set_mouse_encoding() - Mode setters:
set_focus_tracking(),set_bracketed_paste(),set_title() - Bold brightening control:
bold_brightening(),set_bold_brightening() - Faint text alpha control:
faint_text_alpha(),set_faint_text_alpha() - Color getters for all theme colors (link, bold, cursor guide, badge, match, selection)
- New
What's New in 0.12.0
🐛 Bug Fixes
- Terminal Reflow Improvements: Multiple fixes to scrollback and grid reflow behavior during resize
What's New in 0.11.0
🎉 New Features
- Full Terminal Reflow on Width Resize: Both scrollback AND visible screen content now reflow when terminal width changes
- Previously, width changes cleared scrollback and clipped visible content
- Now implements intelligent reflow similar to xterm and iTerm2:
- Scrollback: Preserves all history with proper line wrapping/unwrapping
- Visible Screen: Content wraps instead of being clipped when narrowing
- Width increase: Unwraps soft-wrapped lines into longer lines
- Width decrease: Re-wraps lines that no longer fit
- Preserves all cell attributes (colors, bold, italic, etc.)
- Handles wide characters (CJK, emoji) correctly at line boundaries
- Significant UX improvement for terminal resize operations
What's New in 0.10.0
🎉 New Features
-
Emoji Sequence Preservation: Complete support for complex emoji sequences and grapheme clusters
- ⚠️ vs ⚠ - Variation selectors (emoji vs text style)
- 👋🏽 - Skin tone modifiers (Fitzpatrick scale)
- 👨👩👧👦 - ZWJ sequences (family emoji)
- 🇺🇸 🇬🇧 - Regional indicator flags
- é - Combining diacritics and marks
- New
graphememodule for Unicode cluster detection - Enhanced Python bindings export full grapheme clusters
-
Web Terminal Frontend: Modern Next.js-based web interface
- Built with Next.js, TypeScript, and Tailwind CSS v4
- Theme support with configurable color palettes
- Nerd Font support for file/folder icons
- New Makefile targets for web frontend development
-
Terminal Sequence Support:
- CSI 3J - Clear scrollback buffer command
- Improved cursor positioning for snapshot exports
🐛 Bug Fixes
- Graphics now properly preserved when scrolling into scrollback buffer
- Sixel content saved to scrollback during large scrolling operations
- Kitty Graphics Protocol animation parsing fixes (base64 encoding, frame actions)
⚠️ Breaking Changes (Rust API only)
Cellstruct no longer implementsCopy(nowCloneonly)- Required for variable-length grapheme cluster storage
- All cell copy operations now require explicit
.clone()calls - Python bindings are unaffected - no changes needed in Python code
- Performance impact is minimal due to efficient cloning
What's New in 0.9.1
- Theme Rendering Fix: Fixed theme color palette application in Python bindings
What's New in 0.9.0
-
Graphics Protocol Support: Comprehensive multi-protocol graphics implementation
- iTerm2 Inline Images (OSC 1337): PNG, JPEG, GIF support with base64 encoding
- Kitty Graphics Protocol (APC G): Advanced image placement with reuse and animations
- Sixel Graphics: Enhanced with unique IDs and configurable cell dimensions
- Unified
GraphicsStorewith scrollback support and memory limits - Animation support with frame composition and timing control
- Graphics dropped event tracking for resource management
-
Pre-built Streaming Server Binaries: Download ready-to-run binaries from GitHub Releases
- Linux (x86_64, ARM64), macOS (Intel, Apple Silicon), Windows (x86_64)
- No compilation needed - just download and run
- Includes separate web frontend package (tar.gz/zip) for serving the terminal interface
- Published to crates.io for Rust developers:
cargo install par-term-emu-core-rust --features streaming
See CHANGELOG.md for complete version history.
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 Notifications - Desktop-style alerts and notifications
- 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()andget_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=withinline=0for host-to-terminal downloads,RequestUploadfor 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
SnapshotManagerandReplaySession - C-Compatible FFI -
#[repr(C)]types (SharedState,SharedCell) and C API (terminal_get_state,terminal_add_observer) for embedding in C/C++ applications
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 - 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
Screenshots and Export
- Multiple Formats - PNG, JPEG, BMP, SVG (vector), 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
- 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
- Rust Usage - Using the library in pure Rust projects
- Graphics Testing - Testing graphics protocol implementations
Installation
From PyPI
# or
From Source
Requires Rust 1.75+ and Python 3.12+:
# Install maturin (build tool)
# Build and install
Building a Wheel
# or
Using as a Rust Library
The library can be used in pure Rust projects without Python. Choose your feature combination:
| Use Case | Cargo.toml | What's Included |
|---|---|---|
| Rust Only | par-term-emu-core-rust = { version = "0.10", default-features = false } |
Terminal, PTY, Macros |
| Rust + Streaming | par-term-emu-core-rust = { version = "0.10", default-features = false, features = ["streaming"] } |
+ WebSocket/HTTP server |
| Python Only | par-term-emu-core-rust = "0.10" |
+ Python bindings |
| Everything | par-term-emu-core-rust = { version = "0.10", features = ["full"] } |
All features |
Download pre-built streaming server (recommended):
Pre-built binaries and web frontend packages are available from GitHub Releases:
# Download binary (Linux example)
# Download web frontend
# Run
Available binaries: Linux (x86_64, ARM64), macOS (Intel, Apple Silicon), Windows (x86_64)
Or install from crates.io:
Or build from source:
See docs/RUST_USAGE.md for detailed Rust API documentation and examples.
Optional Components
Terminfo Installation
For optimal terminal compatibility, install the par-term terminfo definition:
# Install for current user
# Or install system-wide
# Then use
See terminfo/README.md for details.
Shell Integration
Enhances terminal with semantic prompt markers, command status tracking, and smart selection:
See shell_integration/README.md for details.
Quick Start
Basic Terminal Emulation
# Create terminal
=
# Process ANSI sequences
# Get content and cursor position
, =
PTY (Interactive Shell)
# Create PTY terminal and spawn shell
# Send commands
# Get output
# Resize terminal
# Exit shell
# 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):
# Spawn with custom environment variables
# Outputs: hello
# Spawn with custom working directory
# Outputs: /tmp
# Combine both
The spawn() method also accepts env and cwd parameters:
Screenshots
=
# Save screenshot
# Vector graphics!
# Styled HTML
# Custom configuration
Color Utilities
# iTerm2-compatible contrast adjustment
=
# WCAG accessibility checks
=
# Color conversions
= # "#FF8040"
= # (255, 128, 64)
= # Purple
Macro Recording and Playback
# Create a macro manually
=
# Wait 500ms
# Trigger screenshot
# Save to YAML
# Load and play back
=
# Load macro from file
=
# Play the macro
# Normal speed
# Tick to execute macro events
# Returns True if event was processed
# Small delay for visual effect
# Check for screenshot triggers
=
# Convert a recording to a macro
=
# Convert and save
=
Examples
See the examples/ directory for comprehensive examples:
Basic Examples
basic_usage_improved.py- Enhanced basic usagecolors_demo.py- Color supportcursor_movement.py- Cursor controltext_attributes.py- Text stylingunicode_emoji.py- Unicode/emoji supportscrollback_demo.py- Scrollback buffer usage
Advanced Features
alt_screen.py- Alternate screen buffermouse_tracking.py- Mouse eventsbracketed_paste.py- Bracketed pastesynchronized_updates.py- Flicker-free renderingshell_integration.py- OSC 133 integrationtest_osc52_clipboard.py- SSH clipboardtest_kitty_keyboard.py- Kitty keyboard protocolhyperlink_demo.py- Clickable URLsnotifications.py- Desktop notificationsrectangle_operations.py- VT420 rectangle ops
Graphics and Export
display_image_sixel.py- Sixel graphicstest_sixel_simple.py- Simple sixel examplestest_sixel_display.py- Advanced sixel displayscreenshot_demo.py- Screenshot featuresfeature_showcase.py- Comprehensive TUI showcase
PTY Examples
pty_basic.py- Basic PTY usagepty_shell.py- Interactive shellspty_resize.py- Dynamic resizingpty_event_loop.py- Event loop integrationpty_mouse_events.py- Mouse in PTYpty_custom_env.py- Custom environment variablespty_multiple.py- Multiple PTY sessionspty_with_par_term.py- Integration with par-term
Terminal Streaming
streaming_demo.py- Python WebSocket streaming serverstreaming_client.html- Browser-based terminal client
Macros and Automation
demo.yaml- Example macro definition
Standalone Rust Server:
# Build and run (default: ws://127.0.0.1:8080)
# Run with authentication
# Or use cargo directly
# With authentication
# With system resource stats (CPU, memory, disk, network)
# Install globally
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
# Run streamer with web frontend
# Open browser to http://localhost:8080
See web_term/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
# Development server (runs on port 8030)
# Build for production (outputs to out/)
# Copy to web_term for serving
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.cssafter 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 (1.75+) - 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
# Run Python 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
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 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
