POS Drag-Drop Designer Module

I’m extending my PHP / MySQL POS and need a self-contained HTML5 drag-and-drop canvas that lets staff create and store printable assets. The tool must:

• Handle multiple document types: invoices, barcode labels, ID cards, and certificates, each on A4 or any user-defined paper size.
• Offer a visual canvas—users drag items into place, set fonts, colours, sizes, and then save the layout to MySQL for future reuse.
• Expose the saved layouts to a generator screen: once products and required quantities are chosen, it should batch-render the correct number of barcodes or an invoice instance, then push everything straight to the browser’s print dialogue.

Code needs to slot cleanly into my current code-base (plain PHP, procedural style) and keep front-end dependencies light—vanilla JS or a small, open-source library is fine.

Deliverables
1. Responsive HTML5 canvas with drag-drop controls.
2. PHP endpoints to save, load, and version designs in MySQL.
3. Dynamic generator that merges product data, auto-creates barcodes (Code128 preferred) and prepares print-ready output.
4. Quick setup guide so I can wire it into the existing POS.

If you have built something similar, I’d love to see a demo or screenshots along with your bid.