> For the complete documentation index, see [llms.txt](https://osl.mistium.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://osl.mistium.com/standard-library/media/qr.md).

# qr

Use `qr` for QR codes, simple barcode-like outputs, and saving generated codes as image files.

```osl
import "std:qr"
```

## API reference

### `qr`

| Method                                                                     | Returns   | Notes                                                                    |
| -------------------------------------------------------------------------- | --------- | ------------------------------------------------------------------------ |
| `qr.generate(data: any, size: any, outputFile: any)`                       | `boolean` | Writes a QR code to a PNG file.                                          |
| `qr.generateColored(data: any, size: any, colorArg: any, outputFile: any)` | `boolean` | Uses the same payload/size normalization with a custom foreground color. |
| `qr.generateToDataURL(data: any, size: any)`                               | `string`  | Uses the same normalized raster as a base64 PNG data URL.                |
| `qr.calculateModuleCount(data: string)`                                    | `number`  |                                                                          |
| `qr.generateQRMatrix(data: string, size: number)`                          | `[]array` |                                                                          |
| `qr.calculateModules(data: string)`                                        | `array`   |                                                                          |
| `qr.addFinderPatterns(matrix: []array)`                                    | `void`    | Adds finder patterns.                                                    |
| `qr.addAlignmentPatterns(matrix: []array)`                                 | `void`    | Adds alignment patterns.                                                 |
| `qr.addTimingPatterns(matrix: []array)`                                    | `void`    | Adds timing patterns.                                                    |
| `qr.addVersionInfo(matrix: []array)`                                       | `void`    | Adds version info.                                                       |
| `qr.getAlignmentPositions(size: number)`                                   | `array`   | Returns alignment positions.                                             |
| `qr.shouldAvoidAlignment(x: number, y: number, size: number)`              | `boolean` | Reports whether a position overlaps a finder-pattern margin.             |
| `qr.generate128(data: any)`                                                | `boolean` | Validates data and writes a Code 128-style barcode PNG.                  |
| `qr.generateEAN13(data: any)`                                              | `boolean` | Validates 12 digits and writes an EAN-13 barcode PNG.                    |
| `qr.generateUPCA(data: any)`                                               | `boolean` | Validates 11 digits and writes a UPC-A barcode PNG.                      |
| `qr.generateCode39(data: any)`                                             | `boolean` | Validates Code 39 characters and writes a barcode PNG.                   |
| `qr.generateBarcode(data: any, length: any)`                               | `string`  | Generates a numeric barcode string of the requested length.              |
| `qr.generateSimpleBarcode(data: string)`                                   | `string`  |                                                                          |
| `qr.generateCode39Barcode(data: any)`                                      | `string`  | Uppercases and validates Code 39 text before adding start/stop markers.  |
| `qr.calculateChecksum(data: string)`                                       | `string`  |                                                                          |
| `qr.verifyBarcode(data: any)`                                              | `boolean` | Verifies barcode.                                                        |
| `qr.writeBarcode(barcode: string, data: any)`                              | `boolean` | Writes barcode.                                                          |
| `qr.scanBarcode(imagePath: any)`                                           | `string`  |                                                                          |
| `qr.getInfo(filePath: any)`                                                | `object`  | Returns info.                                                            |
| `qr.decode(imagePath: any)`                                                | `string`  | Returns the current explicit not-implemented diagnostic.                 |

## Notes

* Prefer `import "std:qr"`; the older `import "osl/qr"` spelling remains supported.

## Behavior and limits

QR payloads are limited to 2,953 bytes and generated images to 4,096 pixels per side. Barcode helpers reject invalid numeric input. PNG creation, encoding, and file-close errors are reported.