Overlay Mode: The Invisible Voice Bar

What Is Overlay Mode?

Overlay Mode is VoxBar's floating interface system. When activated, the main application window hides and is replaced by a small, transparent voice bar that sits on top of every other window on your desktop. You speak, and your words appear in the overlay bar — visible but non-intrusive.

The idea is simple: you should be able to dictate into any application — Word, VS Code, Outlook, a browser — without switching windows. Overlay Mode makes the transcription visible without leaving your current workflow.

Transparency & Appearance

The overlay bar's transparency is fully adjustable. At low opacity, it's nearly invisible — just a faint ribbon of text floating over your screen. At high opacity, it's a readable, focused textbox. You control the slider in real-time; there's no need to restart.

Font size is also adjustable, so you can make the text large enough for a presentation or small enough to tuck into a corner of your screen during code reviews.

Block Mode vs. Line Mode

Overlay Mode supports two display modes:

• Line mode — a single-line entry widget, similar to a search bar. Text scrolls horizontally as you talk. Best for quick dictation where you want minimal screen real estate.
• Block mode — a multi-line textbox that wraps text vertically. Best for longer dictation sessions where you want to see the full context of what you've said.

You can switch between modes on the fly. The text content is preserved when you switch.

Mid-Text Insertion

This is one of Overlay Mode's most powerful features. Instead of always appending new speech to the end of your text, you can click anywhere in the overlay bar to position your cursor. When you start speaking again, the new speech is inserted at that position.

This lets you go back and add a forgotten sentence, insert a correction in the middle of a paragraph, or build out an outline non-linearly. The cursor position is synchronised between the overlay bar and the main textbox — when you switch back to Standard View, everything is in the right place.

Voice Commands

Overlay Mode supports voice-driven editing:

The Technical Challenge: Cursor Sync

The overlay bar is a separate Tk widget from the main textbox. Keeping their state synchronised — cursor position, text content, selection highlights — is one of the more intricate parts of the VoxBar codebase.

The implementation uses exportselection=False on the internal widgets to prevent unintended selection behaviour across focus changes. When you click to reposition the cursor in the overlay bar, the position is captured via index("insert") and mirrored to the main textbox. When new speech arrives, it's inserted at the stored position in both widgets simultaneously.

Preserving cursor position during active speech — while new text is being inserted around the cursor — requires careful coordination between the transcription callback and the UI update loop. VoxBar stores the text-before-cursor string and uses its length to recalculate the insertion point after each update.

Always On Top

Overlay Mode sets the topmost window attribute, ensuring the overlay bar stays above all other windows. Combined with transparency, this creates the "invisible layer" effect — you can see your application underneath, with transcribed text floating on top.

The overlay bar is draggable, so you can position it wherever it's least intrusive for your current task. Position is remembered across sessions.

Available in Every Tier

Overlay Mode is not a premium feature — it's included in every VoxBar product, including VoxBar Free. Whether you're using the $0 Whisper engine or the $49 Voxtral flagship, Overlay Mode works identically.

This was a deliberate design decision. We believe the overlay experience is fundamental to how VoxBar should work, not an upsell.

Use Cases

• Email dictation — Overlay Mode floating over Outlook or Gmail. Speak your reply, copy-paste when done.
• Code narration — Float over VS Code while describing what your code does. Great for documentation.
• Meeting notes — System audio + Overlay Mode = live meeting captions that float over your Zoom window.
• Medical dictation — Float over your EHR system. Speak notes without switching windows.
• Live streaming — Use as on-screen captions for OBS or Streamlabs.