# Open-source credits

> Open-source software and data used by ToolAdda OMR, with their licenses: QR code generation, QR code reading, PDF rendering and font metrics.

Source: https://omrsheet.tooladda.online/credits/

The sheet layout engine, vector PDF writer, image processing and scoring are written specifically for this site. The following third-party components are included, and their license files are distributed with the site.

| Component | Used for | License |
| --- | --- | --- |
| [QR Code Generator](https://github.com/kazuhikoarase/qrcode-generator) by Kazuhiko Arase | Creating the QR code printed on each sheet | MIT |
| [jsQR](https://github.com/cozmo/jsQR) | Reading QR codes in browsers without a built-in barcode reader | Apache License 2.0 |
| [PDF.js](https://mozilla.github.io/pdf.js/) by Mozilla | Opening scanned PDF files in the checker | Apache License 2.0 |
| [@pdf-lib/standard-fonts](https://github.com/Hopding/standard-fonts) | Helvetica character widths for exact text layout in PDFs (based on Adobe's Core 14 font metrics) | MIT |

## Trademarks

"QR Code" is a registered trademark of DENSO WAVE INCORPORATED. NEET, JEE, SSC, UPSC and other exam names are used only to describe the style of practice sheet layouts. ToolAdda OMR is not affiliated with or endorsed by the bodies that conduct these exams.

If you maintain one of these projects and would like a correction, please [contact us](https://omrsheet.tooladda.online/contact/).