Cursor IME Indicator

A lightweight VS Code extension that displays the current input language directly above your cursor. Never accidentally type in the wrong language again.

Features

• Inline language indicator — Shows a small label above your cursor so you always know which input language is active.
• Cross-platform — Works on both macOS and Windows with native-level detection.
• Instant detection — Uses native event-driven watchers for real-time input source changes with minimal overhead.
• IME mode aware — Detects 한/영 toggle and CJK IME mode switches, not just keyboard layout changes.
• 25+ languages supported — Korean, English, Chinese, Japanese, and many more out of the box.
• Fully customizable — Adjust font size, opacity, color, and bold style to match your theme.

Supported Platforms

Platform	Primary Detection	Fallback
macOS	Swift native watcher (event-driven, zero polling)	defaults read periodic polling
Windows	C# native helper (IMM API, 200ms polling)	PowerShell periodic polling

Supported Languages

Language	Indicator	Language	Indicator
Korean	한	English	abc
Chinese	中	Japanese	あ
Russian	Ру	Arabic	عر
Thai	ไท	Hindi	हि
Greek	Ελ	Hebrew	עב
German	DE	French	FR
Spanish	ES	Italian	IT
Portuguese	PT	Turkish	TR
Polish	PL	Dutch	NL
Swedish	SV	Norwegian	NO
Danish	DA	Finnish	FI
Czech	CZ	Hungarian	HU
Vietnamese	VI	+ more...

CJK and non-Latin scripts display a representative character from their native writing system. Latin-alphabet languages display the ISO country code. Unknown input sources fall back to a 2-letter abbreviation automatically.

Requirements

• VS Code 1.85.0 or later
• macOS: Xcode Command Line Tools (for first-run native helper compilation; falls back to polling if unavailable)
• Windows: .NET Framework 4.x (pre-installed on Windows 10/11; falls back to PowerShell if unavailable)

Linux support is planned for a future release.

Installation

From VS Code Marketplace

1. Open VS Code
2. Go to Extensions (Cmd+Shift+X / Ctrl+Shift+X)
3. Search for Cursor IME Indicator
4. Click Install

From VSIX

code --install-extension cursor-ime-indicator-0.0.7.vsix

Extension Settings

Setting	Default	Description
cursorImeIndicator.enabled	true	Enable/disable the indicator
cursorImeIndicator.fontSize	0.8	Font size relative to editor font (0.3 ~ 3.0)
cursorImeIndicator.opacity	0.7	Indicator opacity (0.1 ~ 1.0)
cursorImeIndicator.bold	true	Display indicator in bold font
cursorImeIndicator.color	""	Custom text color (empty = cursor color)
cursorImeIndicator.pollingInterval	300	Polling interval in ms (fallback mode only)

Example: Minimal

{
  "cursorImeIndicator.fontSize": 0.5,
  "cursorImeIndicator.opacity": 0.8,
  "cursorImeIndicator.bold": true,
  "cursorImeIndicator.color": "#888888"
}

Commands

Command	Description
Cursor IME Indicator: Toggle	Toggle the indicator on/off

Access via Command Palette (Cmd+Shift+P / Ctrl+Shift+P).

How It Works

macOS

1. Primary: A native Swift helper listens for AppleSelectedInputSourcesChangedNotification via DistributedNotificationCenter. This is fully event-driven — no polling, no CPU overhead.
2. Fallback: If the native helper cannot be compiled (no Xcode CLI tools), the extension falls back to periodic polling via defaults read.

The native helper is automatically compiled on first activation and cached for subsequent sessions.

Windows

1. Primary: A native C# helper uses Win32 APIs (GetKeyboardLayout + IMM ImmGetDefaultIMEWnd) to detect both keyboard layout changes and IME mode switches (e.g., 한/영 toggle). Polls at 200ms intervals and outputs only on change.
2. Fallback: If the C# helper cannot be compiled (no csc.exe), the extension falls back to a PowerShell-based detector with the same IMM API, or a simple periodic polling via InputLanguage API.

The native helper is automatically compiled using csc.exe (.NET Framework) on first activation and cached for subsequent sessions.

Known Issues

• On the first line of a file, the indicator may be partially clipped at the top edge.
• The indicator position may vary slightly depending on editor font and line height settings.

Release Notes

0.0.7

• Windows support with native C# IME detection
• IME mode awareness (한/영 toggle, CJK conversion mode detection)
• 3-tier fallback on Windows (native → PowerShell persistent → PowerShell simple polling)
• Platform-specific detector architecture for easier future platform additions

0.0.1

• Initial release
• macOS input source detection (native watcher + polling fallback)
• 25+ language support with native script indicators
• Customizable appearance (font size, opacity, bold, color)

Contributing

Contributions are welcome! Please feel free to submit issues and pull requests.

License

MIT