RRZE QR

Create, configure, and download QR codes from the QR-Codes menu in WordPress. The workspace uses WordPress components and WordPress's bundled React. QR images are generated locally in the browser; no external QR service receives the URL.

Requirements

• WordPress 6.4 or newer
• PHP 8.2 or newer
• JavaScript enabled in the administration area

QR-Codes workspace

Authors, editors, administrators, and custom roles with permission to edit posts or pages can use the workspace. Enter an HTTP or HTTPS destination URL and adjust:

• Foreground and background: black, white, and FAU blue presets, plus a custom color picker for each
• Transparent background: a separate toggle that remembers the last solid color
• Export size: 300, 600, or 1200 pixels, or a custom square side length from 128 to 4096 pixels (whole numbers)

Test URL opens the normalized destination in a new tab. It is disabled for empty, invalid, or unsupported URLs. It does not check the destination in advance.

The preview updates automatically. Download PNG exports the current code. A transparent preview has a background selector; this affects the preview only, and the downloaded image remains transparent.

Changes apply to the current download. Administrators can explicitly Save as defaults to set the colors and export size for future codes. The destination URL is never saved as a site default. Reset to defaults restores the saved appearance without changing the URL.

Existing color settings are retained when upgrading. Bookmarks to the former Tools and Settings pages redirect to the new workspace.

QR codes from post and page lists

Use Create QR code (QR-Code erstellen) on a published post or page to open its title and current permalink in the workspace. Choose colors and size, preview the result, and download the PNG there. A return link leads back to the source list.

Authors can use the workspace and create QR codes for their own published posts. Editors can also use the row action on other authors' published posts and pages. Access follows WordPress editing permissions and is checked again when opening the workspace. Only administrators can save site defaults.

Downloads use descriptive filenames such as qr-code-contact-42.png while the destination URL matches the selected item. QR scripts and styles load only in the workspace; post and page lists contain a regular link and no QR notices.

Validation and scanning

Validation checks the URL format and QR capacity. It does not visit the URL, check its HTTP status, or guarantee that its destination is reachable. International domain names and paths are normalized to an ASCII URL. URLs longer than 2,953 encoded characters are rejected.

Identical foreground and background colors cannot be downloaded or saved. Other custom colors are allowed, with a warning for low contrast. Choose a dark foreground on a light background for reliable scanning. Transparent codes need a contrasting surface; test codes with the intended scanner and background before publishing or printing. Contrast hints do not guarantee that a code will scan.

PNG exports use error correction level L and include a four-module quiet zone. The exported image keeps the requested square dimensions, with unused pixels added to the margin so QR modules remain sharp. Modules occupy at least two pixels; if the code cannot fit, the image grows to its minimum readable size. The preview shows the final dimensions. Custom sizes can also be saved as site defaults.

Development

npm ci
npm run build
npm test
npm run lint:js
npm run lint:php

The lockfile pins dependencies. Builds regenerate the committed files in assets/ and do not change the plugin version. Use npm run release:patch, npm run release:minor, or npm run release:major explicitly when preparing a release. The release command keeps the plugin header, package manifest, and lockfile versions in sync.

Main constructs Settings and QRCode and registers their WordPress hooks. Settings owns site defaults, validation on save, and migration; QRCode owns the admin workspace, permissions, contextual links, and assets. Utilities provides pure static color and size validation. The PHP lint command checks every PHP file under includes/ and tests/, plus the plugin entry point.

The React workspace has its own entry point in src/js/admin.js. WordPress supplies wp-components, wp-element, wp-i18n, and the components stylesheet. JSX uses the classic transform to support WordPress 6.4. QRious is copied from the locked npm dependency when building.

Automated checks cover QR decoding and capacity, quiet zones, color combinations, contextual workspace access, permissions, default persistence, legacy settings, and asset registration. PHP checks use isolated WordPress stubs and do not change the database. Browser interaction and visual checks are performed manually.

Interface strings use the rrze-qr text domain. PHP and JavaScript German translations are included in languages/. The JavaScript translation map in languages/source-map.json maps source references to the built entry point.

License

Licensed under the GNU General Public License v3.0 or later. See LICENSE and third-party notices.

Developed by the RRZE Webteam, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU).