# Lios
Lios is a polished Rust GTK4/VTE terminal emulator by KnottDynamics and Trevor Knott. It keeps the terminal core reliable by using VTE, then focuses on what should feel better day to day: beautiful built-in themes, glass/background controls, fast same-directory windows, simple config, and an opt-in GPU renderer switch without making unstable GPU paths the default.
## Why Lios
- Uses VTE for real terminal behavior instead of a toy parser.
- Keeps Cairo as the reliable default renderer, with explicit opt-in GPU modes for GTK auto, OpenGL, or Vulkan.
- Treats theming as a core feature, not a plugin: built-in palettes, opacity, background images, accent tint, and live preferences are baked in.
- Opens new windows in the active terminal directory, which keeps shell workflows smooth.
- Stays small: SSH and other extra workflows belong in optional `lios-*` helpers, not the core terminal.
- Avoids telemetry, background downloads, and secret storage.
## Features
- GTK4 window with a VTE terminal widget.
- Spawns `$SHELL`, with common Unix shell fallbacks.
- Optional `-- COMMAND ...` and `--command "..."` launch modes.
- Dark readable defaults: white-on-black palette, opaque dark backing layer, `Monospace 12`, block cursor, 1,000 lines of scrollback.
- Built-in themes: `xfce`, `xterm`, `green-on-black`, `white-on-black`, `dark-pastels`, `solarized-dark`, `solarized-light`, `black-on-white`.
- Slider-based master/full-window opacity plus nested image, terminal shade, and accent opacity controls.
- Background image support with `~` path expansion, fixed color tint, or per-launch random accent tint.
- Explicit visible mouse pointer over the terminal instead of VTE's dark text cursor shape.
- GPU acceleration toggle: reliable `cairo` by default, with opt-in `auto`, OpenGL (`gl`), or Vulkan (`vulkan`) through `GSK_RENDERER` before GTK starts.
- Desktop launcher install with `lios --install` or `lios ---install`.
- App icon installed from `assets/logo.png`.
- Optional window decoration/topbar removal.
- Slim topbar with a collapsible in-window preferences drawer for common live theme/background changes.
- `Ctrl+Shift+N` and `New Window` open a borderless terminal in the active terminal directory.
- Right-click appearance submenus for background images, terminal glass, accent presets, random tint, and themes.
- Right-click diagnostics for active windows, RSS, scrollback, theme, background, and config path.
- Terminal-driven config commands for theming from a shell or script.
- Clipboard/context actions for copy, copy as HTML, paste, select all.
- Keyboard shortcuts for `Ctrl+Shift+C`, `Ctrl+Shift+V`, `Ctrl+Shift+A`, `Ctrl+Shift+N`, `Ctrl+Shift+Q`, `Ctrl+Shift+,`, `Ctrl++`, `Ctrl+-`, and `Ctrl+0`.
## System Dependencies
Install Rust plus GTK4/VTE libraries and headers.
Debian/Ubuntu names:
```sh
sudo apt install pkg-config libgtk-4-dev libvte-2.91-gtk4-dev
```
Arch names:
```sh
sudo pacman -S rust pkgconf gtk4 vte4
```
## Run
Install from crates.io:
```sh
cargo install lios
lios
```
Run from source:
```sh
cargo run
cargo run -- --working-directory "$HOME"
cargo run -- -- htop
cargo run -- --command "ls -la"
cargo run -- --theme solarized-dark
cargo run -- --gpu
cargo run -- --gpu-mode vulkan
cargo run -- --renderer gl
cargo run -- --opacity 0.88
cargo run -- --background-image ~/Pictures/wallpaper.jpg --background-opacity 0.50 --random-overlay
cargo run -- --hide-titlebar
cargo run -- config init
cargo run -- config set gpu on
cargo run -- config set gpu_mode gl
cargo run -- config set theme solarized-dark
cargo run -- config set renderer gl
cargo run -- config set background.image ~/Pictures/wallpaper.jpg
cargo run -- config set topbar false
```
## Optional Plugins
Core Lios stays small. Optional helpers use separate `lios-*` packages.
`lios-ssh` launches OpenSSH inside Lios without storing hosts, passwords, keys, or SSH config:
```sh
cargo install lios-ssh
lios-ssh user@example.com
lios-ssh -p 2222 user@example.com
lios-ssh --theme solarized-dark -- -J jump.example.com user@example.com
```
The helper wraps `lios -- ssh ...` using argv. OpenSSH still handles `~/.ssh/config`, SSH agent, known hosts, keys, jump hosts, and verification.
## Configuration
Lios reads `~/.config/lios/config.toml` by default when it exists. Use `--config path/to/config.toml` to load another file.
```toml
[window]
title = "Lios"
width = 960
height = 640
decorated = true # set false to remove the topbar/window decorations
renderer = "cairo" # cairo disables GPU; auto, gl, or vulkan enable GPU
opacity = 1.00 # master/full-window opacity
[terminal]
font = "Monospace 12"
scrollback_lines = 1000 # max 100000
[theme]
name = "xfce"
# Optional custom overrides:
# foreground = "#ffffff"
# background = "#000000"
# cursor = "#ffffff"
# palette = ["#000000", "#aa0000", "#00aa00", "#aa5500", "#0000aa", "#aa00aa", "#00aaaa", "#aaaaaa", "#555555", "#ff5555", "#55ff55", "#ffff55", "#5555ff", "#ff55ff", "#55ffff", "#ffffff"]
[background]
image = "/home/example/Pictures/wallpaper.jpg"
image_opacity = 1.00
terminal_opacity = 0.50
# Use lower values for more glass/desktop transparency.
# overlay_color = "#7c3aed"
overlay_opacity = 0.00
random_overlay = true
```
CLI flags override the config file for one run. Use `--gpu` for GTK GPU auto-selection, `--gpu-mode gl` or `--gpu-mode vulkan` to force a GPU backend, and `--no-gpu` to force the reliable Cairo renderer. The text config stores this as `window.renderer` so older configs remain valid.
Use `window.opacity` or `--opacity` as the main full-window opacity. This affects the whole terminal UI and is the primary control for app transparency.
Background images are rendered against the theme background and composited below a transparent VTE terminal. `image_opacity` controls how strongly the image blends into the theme-colored base. `terminal_opacity` is the nested terminal shade layer over that image; lower values show more image while preserving readable text. Without an image, use the master opacity for reliable transparent-terminal behavior, then use `terminal_opacity` only as the inner shade. If an older config has an image with `terminal_opacity = 1.00`, Lios uses the image shade at runtime so the image is not hidden by a fully opaque terminal background.
The default topbar includes a `Customize` button when `decorated = true`. It opens a collapsible in-window drawer rather than a separate dialog. `Ctrl+Shift+,` toggles the same drawer, which is useful when the topbar is hidden. `Ctrl+Shift+N` opens another borderless terminal window in the active terminal directory using the current live settings. `Ctrl+Shift+Q` closes the current window. The drawer can change GPU acceleration mode, theme, font, topbar visibility, background image path, master opacity, terminal shade opacity, image opacity, accent opacity, overlay color, and random overlay. Opacity controls are sliders. The background row includes a `Choose Image` button with an image-file picker; chosen images apply immediately and lower terminal shade opacity if needed so the image is visible. Theme/background/font changes apply live; renderer changes are saved and apply on the next launch. Changes are written back to `~/.config/lios/config.toml` when a config path is available.
Right-click inside the terminal for quick actions. `New Window` opens a borderless terminal in the active terminal directory. `Close Window` manages terminal windows. `Diagnostics` prints resource state into the terminal. `Reset to Dark Default` returns the current window to the plain dark default look. The `Opacity` submenu starts with master/full-window opacity controls, then nests terminal shade controls under `Terminal Shade`. The `Background` submenu changes/clears images, adjusts image brightness, or resets the whole background. `Accent` switches fixed accent presets (`Violet`, `Cyan`, `Emerald`, `Amber`, `Rose`), toggles random accent tint, and adjusts accent strength. The `Theme` submenu switches built-in terminal themes. These actions apply live and persist to the active config path when one is available.
## Desktop Launcher
Install or build the binary first, then run `lios --install` to add Lios to the desktop app menu without launching it from another terminal. `lios ---install` is also accepted.
```sh
cargo install --path .
lios --install
```
The command writes `dev.lios.Terminal.desktop` under `$XDG_DATA_HOME/applications` or `~/.local/share/applications` with `Terminal=false` and `Exec` pointing at the exact binary that ran the command. It also installs the app icon from `assets/logo.png` as `dev.lios.Terminal` under the user icon theme and requests a desktop/icon cache refresh when the standard desktop tools are available. Normal GUI startup also makes the packaged icon available to GTK so direct `cargo run` launches can resolve the same icon name. Running `cargo run -- --install` creates a launcher for `target/debug/lios`; use the installed `lios --install` command for a stable app-menu entry. Use `lios --uninstall` or `lios ---uninstall` to remove that launcher and icon.
## Resource Policy
- Terminal scrollback is bounded. `scrollback_lines` must be between `0` and `100000`; the default is `1000`.
- Runtime diagnostics show active windows, process RSS, scrollback limit, renderer, theme, background image, opacity, overlay state, and config path.
- GTK callbacks that can outlive their parent window use weak window references to avoid reference cycles during repeated open/close cycles.
- Segmented preference controls store weak button references internally, avoiding self-cycles between buttons and their click closures.
- No Tokio tasks or channels are used; child processes are owned by VTE and tied to the terminal widget/window lifecycle.
Rust `1.88.0` can ICE while compiling generated GTK binding crates with heavy debug or optimization settings. `Cargo.toml` keeps the workaround scoped to the affected GTK crates. If `cargo install` still crashes while compiling GTK dependencies with a rustc stack trace, retry with a larger compiler stack:
```sh
RUST_MIN_STACK=16777216 cargo install --path .
```
Terminal config commands:
```sh
lios config path
lios config sample
lios config init
lios config init --force
lios config show
lios config set gpu on
lios config set gpu_mode vulkan
lios config set renderer gl
lios config set theme solarized-dark
lios config set opacity 0.88
lios config set background_opacity 0.80
lios config set overlay_color '#7c3aed'
lios config set overlay_opacity 0.18
lios config set random_overlay true
lios config set topbar false
lios --install
lios ---install
lios --uninstall
```
Useful keys include `gpu`, `gpu_mode`, `renderer`, `theme`, `font`, `opacity`, `background.image`, `background_opacity`, `background_image_opacity`, `overlay_color`, `overlay_opacity`, `random_overlay`, and `topbar`.
## Package
The Cargo package is named `lios` and includes crate metadata for packaging.
```sh
cargo publish --dry-run
cargo publish
```