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Textmode Overlay is a free, open-source browser extension built with textmode.js. It turns compatible <canvas> and <video> elements into live ASCII/textmode overlays that you can style, adjust, and export.
- Live conversion: Render a customizable ASCII grid over a compatible canvas or video.
- Media picker: Select visible media in the page, including supported same-origin and nested frames.
- Visual controls: Adjust brightness, contours, colors, glyph ramps, fonts, opacity, and post-processing effects.
- Custom fonts: Upload local
.ttfor.otffonts for your own character style. - Exports: Save a frame as TXT, SVG, PNG, or JPG.
| Browser | Build | Output | Store |
|---|---|---|---|
| Chrome | npm run build:chrome |
.output/chrome-mv3 |
Chrome Web Store |
| Opera | npm run build:opera |
.output/chrome-mv3-opera |
Opera Add-ons |
| Edge | npm run build:edge |
.output/edge-mv3 |
Edge Add-ons |
| Firefox | npm run build:firefox |
.output/firefox-mv3 |
Firefox Add-ons |
| Safari | npm run build:safari |
.output/safari-mv2 |
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Requirements:
Install dependencies:
npm installRun the full verification pipeline:
npm run checkBuild the unpacked Chrome extension:
npm run build:chromeLoad the extension in Chrome:
- Open
chrome://extensions. - Enable Developer mode.
- Click Load unpacked.
- Select
.output/chrome-mv3.
Upload a local TrueType (.ttf) or OpenType (.otf) font from the in-page panel. Fonts stay in the current browser profile; they are not synced or uploaded. Files over 10 MB are rejected, and the extension supports up to 10 fonts and 50 MB of font data in total.
Textmode Overlay accesses a page only after you invoke it from the toolbar or context menu. Rendering, settings, fonts, and exports stay in your browser. The extension has no backend, account synchronization, analytics, advertising, or remote telemetry, and it does not transmit page content or exports.
The extension uses activeTab, contextMenus, scripting, storage, and unlimitedStorage. It does not request permanent host permissions.
See the Imprint and Privacy Policy for the complete disclosures covering the extension and extension.textmode.art landing page.
- Open a page with a visible canvas or video element.
- Click the Textmode Overlay toolbar icon, or right-click the page and choose Open Textmode Overlay.
- In the panel, choose select media, then click a highlighted canvas or video.
- Adjust the effect or export a frame from the panel.
Note
Some media cannot be sampled. Cross-origin, tainted, DRM-protected, or otherwise restricted media may fail when the browser blocks WebGL or canvas pixel access.
Development workflow, testing, architecture, and contribution guidelines live in CONTRIBUTING.md.
Textmode Overlay is licensed under the MIT License.