Projects / rt

git clone https://molodetz.nl/retoor/rt.git

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RT Terminal

RT (Rapid Terminal) is a terminal emulator implemented in C11 using GTK4 and VTE. The application provides hardware-accelerated rendering, complete ANSI escape sequence processing, and POSIX-compliant pseudoterminal management.

Technical Specifications

| Component | Implementation | |-----------|----------------| | Language | C11 (ISO/IEC 9899:2011) | | UI Toolkit | GTK4 (4.10+) | | Terminal Backend | VTE 2.91-gtk4 (0.76+) | | Font Rendering | FreeType2 with Pango/Cairo | | PTY Interface | UNIX 98 pseudoterminals | | Build System | Meson + Ninja | | Binary Size | ~115KB (stripped) |

Architecture 

rt/
├── src/
│   ├── main.c                 # Entry point, environment setup
│   ├── rt-application.c/h     # GtkApplication lifecycle
│   ├── rt-window.c/h          # Window management, actions
│   ├── rt-terminal.c/h        # VTE wrapper, shell spawning
│   ├── rt-tabs.c/h            # Tab container management
│   ├── rt-config.c/h          # INI configuration parser
│   ├── rt-theme.c/h           # Color palette management
│   ├── rt-font.c/h            # Font description, DPI scaling
│   ├── rt-pty.c/h             # PTY allocation (unused, VTE handles)
│   ├── rt-ansi.c/h            # ANSI sequence validator
│   ├── rt-clipboard.c/h       # Clipboard, OSC 52 handler
│   ├── rt-shortcuts.c/h       # Keyboard accelerators
│   └── rt-utils.c/h           # Path resolution, color parsing
├── data/
│   ├── rt.desktop             # XDG desktop entry
│   └── rt.svg                 # Application icon
└── config/
    └── rt.conf.example        # Configuration template

Rendering Pipeline

RT configures FreeType2 interpreter version 40 for improved glyph rendering: 

FREETYPE_PROPERTIES=truetype:interpreter-version=40

Font rendering parameters:

  • Antialiasing: Subpixel (CAIRO_ANTIALIAS_SUBPIXEL)
  • Hint Style: Full (CAIRO_HINT_STYLE_FULL)
  • Hint Metrics: Enabled (CAIRO_HINT_METRICS_ON)
  • Subpixel Order: RGB (CAIRO_SUBPIXEL_ORDER_RGB)

These settings are applied per-widget via pango_cairo_context_set_font_options() .

Differentiation from GNOME Terminal

| Aspect | RT | GNOME Terminal | |--------|----|----| | Toolkit | GTK4 native | GTK4 (migrated) | | Configuration | INI file | dconf/GSettings | | Theme System | Built-in palettes | Profile-based | | Font Config | Direct FreeType control | System defaults | | Startup | Single GObject chain | Full GNOME integration | | Dependencies | Minimal (5 libraries) | GNOME platform |

Color Support

ANSI 16-Color Palette

Standard SGR codes 30-37 (foreground) and 40-47 (background) with bright variants 90-97/100-107.

256-Color Mode

Extended palette via ESC[38;5;{n}m and ESC[48;5;{n}m :

  • 0-15: Standard ANSI colors
  • 16-231: 6x6x6 color cube (r * 36 + g * 6 + b + 16)
  • 232-255: Grayscale ramp (24 shades)

24-bit Truecolor

Direct RGB specification via ESC[38;2;{r};{g};{b}m and ESC[48;2;{r};{g};{b}m .

Environment variables set by RT: 

TERM=xterm-256color
COLORTERM=truecolor

Built-in Themes

| Theme | Background | Foreground | |-------|------------|------------| | Dracula | #282a36 | #f8f8f2 | | Nord | #2e3440 | #d8dee9 | | Solarized Dark | #002b36 | #839496 | | Solarized Light | #fdf6e3 | #657b83 | | Gruvbox | #282828 | #ebdbb2 |

All themes implement the full 16-color ANSI palette with theme-appropriate mappings.

Dependencies

Runtime Libraries

| Library | Minimum Version | Purpose | |---------|-----------------|---------| | GTK4 | 4.10 | UI toolkit | | VTE | 0.76 | Terminal widget | | FreeType2 | 2.10 | Font rasterization | | Pango | 1.50 | Text layout | | Cairo | 1.16 | 2D rendering | | GLib | 2.74 | Core utilities |

Build Dependencies

| Tool | Purpose | |------|---------| | GCC/Clang | C11 compiler | | Meson | Build configuration | | Ninja | Build execution | | pkg-config | Dependency resolution |

Installation Commands

Debian/Ubuntu: 

apt install build-essential meson ninja-build pkg-config \
    libgtk-4-dev libvte-2.91-gtk4-dev libfreetype-dev \
    libpango1.0-dev libcairo2-dev

Fedora: 

dnf install gcc meson ninja-build pkg-config \
    gtk4-devel vte291-gtk4-devel freetype-devel \
    pango-devel cairo-devel

Arch Linux: 

pacman -S base-devel meson ninja gtk4 vte4 freetype2 pango cairo

Build Instructions

Release build: 

meson setup build --buildtype=release --prefix=/usr
meson compile -C build

Debug build: 

meson setup build --buildtype=debug -Denable_debug_logging=true
meson compile -C build

Using Make wrapper: 

make release    # Optimized build
make debug      # Debug symbols
make install    # Install to PREFIX
make run        # Build and execute

Installation

System-wide: 

meson install -C build

Or via Make: 

make PREFIX=/usr install

Configuration

Location: ~/.config/rt/rt.conf 

[font]
family=JetBrains Mono
size=11
antialiasing=true
hinting=true
subpixel=true

[theme]
name=Dracula

[terminal]
scrollback_lines=10000
scroll_on_output=false
scroll_on_keystroke=true
bold_is_bright=true
cursor_blink=true
cursor_shape=block

[bell]
audible=false
visual=true

[shell]
command=/bin/bash

Cursor Shapes

  • block - Filled rectangle
  • ibeam - Vertical line
  • underline - Horizontal line

Keyboard Shortcuts

| Action | Accelerator | |--------|-------------| | Copy | <Ctrl><Shift>c | | Paste | <Ctrl><Shift>v | | New Tab | <Ctrl><Shift>t | | Close Tab | <Ctrl><Shift>w | | Next Tab | <Ctrl>Page_Down | | Previous Tab | <Ctrl>Page_Up | | New Window | <Ctrl><Shift>n | | Zoom In | <Ctrl>plus | | Zoom Out | <Ctrl>minus | | Zoom Reset | <Ctrl>0 | | Fullscreen | F11 | | Quit | <Ctrl>q |

Shortcuts are configurable via the [shortcuts] section in rt.conf .

Clipboard Integration

Standard Clipboard

GTK4 clipboard API with support for:

  • Primary selection (middle-click paste)
  • Clipboard selection (Ctrl+Shift+C/V)

OSC 52

Remote clipboard access via escape sequence: 

ESC ] 52 ; c ; <base64-data> BEL

Selection targets:

  • c - Clipboard
  • p - Primary
  • s - Secondary

Signal Handling

The terminal forwards signals to child processes:

  • SIGWINCH - Window resize notification
  • SIGHUP - Hangup on terminal close
  • SIGTERM - Graceful termination request

Environment

Variables set for child processes: 

TERM=xterm-256color
COLORTERM=truecolor
SHELL=<user shell>

File Locations

| Path | Purpose | |------|---------| | ~/.config/rt/rt.conf | User configuration | | /usr/share/rt/rt.conf | Default configuration | | /usr/share/applications/rt.desktop | Desktop entry | | /usr/share/icons/hicolor/scalable/apps/rt.svg | Application icon |

Exit Codes

| Code | Meaning | |------|---------| | 0 | Normal termination | | 1 | GTK initialization failure | | 127 | Shell execution failure |

License

MIT License. See LICENSE file.

Source

13 component modules, approximately 3,500 lines of C code.

Files

  • Makefile 8.3 KB raw
  • README.md 7.0 KB raw
  • config
  • data
  • meson_options.txt 194 B raw
  • src