Viet+

Vietnamese Input Method for Linux
_{Zero underline • No pre-edit buffer • Backspace-Replay sync • Built in Rust}

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What is Viet+?

Viet+ is a Vietnamese input method for Linux that takes a fundamentally different approach from every other IME: Direct Input.

Most Vietnamese IMEs use a pre-edit buffer — you type into a temporary buffer with an ugly underline, and the text only becomes real Vietnamese when you commit it. This causes duplicate text, underline distraction, broken copy/paste, and desync between the engine state and what's on screen.

Viet+ eliminates all of this. Keystrokes are instantly converted to Unicode — what you type is what you see. No buffer. No underline. No duplication.

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Features

Feature	How It Works
Direct Input	No pre-edit buffer. Keystrokes instantly become text via uinput injection
VNI & Telex	Both input methods fully supported, switchable at runtime via Ctrl+Shift
Bamboo Engine	Transformation model — composition, marks, tones, flexible backtracking
Smart Clusters	uo→ươ with backtrack, ua→ưa horn placement
Macro Expansion	ko → không, dc → được, add your own
Casing Preservation	Tieengs → Tiếng, TIEENGS → TIẾNG
App Memory	Per-app Vietnamese/English state, saved to overrides.toml
Hot Reload	Config changes apply without restart
Window-Switch Reset	Engine clears automatically on Alt+Tab
CPU Priority	Pinned to P-cores (0-3) + nice(-10) for low-latency input
Uinput Injection	/dev/uinput for reliable injection on X11 and Wayland
Password Auto-Detection	4 layers: AT-SPI2 → sudo process → window-title → window-class
Tray Icon	Shows current mode: Red VN / Blue TLX / Gray EN
GNOME/Wayland	Native GNOME Shell D-Bus integration

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Input Methods

Both VNI and Telex are fully supported. Switch via Ctrl+LeftShift or the tray menu.

VNI

Key	Result	Example
1	á (sắc)	a1 → á
2	à (huyền)	a2 → à
3	ả (hỏi)	a3 → ả
4	ã (ngã)	a4 → ã
5	ạ (nặng)	a5 → ạ
6	â/ê/ô	a6→â, e6→ê, o6→ô
7	ơ/ư	o7→ơ, u7→ư
8	ă	a8→ă
9	đ	d9→đ

Telex

Key	Result	Example
s	á (sắc)	as→á
f	à (huyền)	af→à
r	ả (hỏi)	ar→ả
x	ã (ngã)	ax→ã
j	ạ (nặng)	aj→ạ
aa	â	aa→â
ee	ê	ee→ê
oo	ô	oo→ô
ow	ơ	ow→ơ
aw	ă	aw→ă
uw	ư	uw→ư
dd	đ	dd→đ
w	ươ	chuongw→chương

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Key Bindings

Combo	Action
Ctrl+Space	Toggle Vietnamese ON/OFF
Ctrl+LeftShift	Toggle VNI ↔ Telex

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Password Detection

4-layer automatic detection. When a password field is detected, Vietnamese is automatically disabled:

Layer	Method	Detects
1	AT-SPI2 D-Bus (a11y role check)	Password fields in accessible apps
2	Process tree (pstree)	sudo / passwd in terminal
3	Window title keywords	password, sudo in title
4	Window class matching	pinentry, polkit, kwallet dialogs

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Installation

One-Command Install (recommended)

Works on both Linux Mint and Ubuntu (including 24.04+ Wayland):

git clone https://github.com/vndangkhoa/vietc.git /tmp/vietc \
  && cd /tmp/vietc && sudo ./install.sh

The script will:

1. Install build + runtime dependencies
2. Compile all binaries
3. Install to /usr/bin/
4. Set up uinput udev rules
5. Add your user to the input group

After install: Log out and log back in, then launch vietc-tray from your application menu.

Manual Build & Run

# Install dependencies
sudo apt install git curl build-essential pkg-config \
  libx11-dev libxtst-dev libevdev-dev libdbus-1-dev wl-clipboard

# Enable accessibility (Ubuntu Wayland — for password detection)
gsettings set org.gnome.desktop.a11y.applications screen-reader-enabled true

# Build
git clone https://github.com/vndangkhoa/vietc.git
cd vietc
cargo build --release

# Run (Mint — no sudo needed for uinput)
./target/release/vietc

# Run (Ubuntu — needs sudo for keyboard grab)
sudo ./target/release/vietc

Uninstall

sudo ./uninstall.sh

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Configuration

Config file: ~/.config/vietc/config.toml or ./vietc.toml

input_method = "vni"            # "vni" or "telex"
toggle_key = "space"            # Ctrl+Space to toggle VN/EN
toggle_method_key = "shift"     # Ctrl+Shift to toggle VNI/Telex
start_enabled = true            # Vietnamese by default
grab = true                     # grab keyboard (evdev)

[password_detection]
enabled = true
check_atspi2 = true
check_window_title = true
title_keywords = ["password", "passphrase", "secret", "mật khẩu", "sudo"]
password_apps = ["pinentry", "pinentry-gtk-2", "pinentry-qt",
  "lxqt-sudo", "kdesudo", "gksudo",
  "polkit-gnome-authentication-agent-1",
  "kwallet", "gnome-keyring", "ssh-askpass"]

[app_state]
enabled = true
english_apps = ["code", "vim", "kitty", "foot"]
vietnamese_apps = ["telegram", "discord", "firefox"]
bypass_apps = ["kitty", "alacritty", "steam"]

[macros]
ko = "không"
dc = "được"
vs = "với"

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Architecture

vietc/
├── engine/                  # Vietnamese composition engine (bamboo-core port)
├── protocol/                # Keyboard capture & injection
│   ├── uinput_monitor.rs    # /dev/uinput injection (primary)
│   ├── x11_inject.rs        # XTest injection (fallback)
│   ├── x11_capture.rs       # XRecord key capture
│   └── wayland_im.rs        # Wayland IM protocol (stub)
├── daemon/                  # Main daemon process
│   ├── main.rs              # Event loops, grab, signal handling
│   ├── config.rs            # TOML config loader + hot reload
│   ├── app_state.rs         # Per-app VN/EN memory + password detection
│   ├── password_detector.rs # AT-SPI2 D-Bus password field detection
│   └── display.rs           # X11/Wayland/compositor detection
├── ui/                      # System tray icon (ksni)
│   └── tray.rs              # Tray with VN/TLX/EN mode display
├── cli/                     # Interactive test harness
└── uinputd/                 # Privileged uinput socket daemon

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License

MIT License — see LICENSE for details.

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_{Made with love for the Vietnamese Linux community}