DanhThong Print Design Upload adds a simple product customizer to WooCommerce products.

Features:
* Enable/disable design upload per product.
* Customer uploads an image on the product page.
* The uploaded image is added as a movable/resizable layer on a canvas (Fabric.js).
* The product image can be used as the canvas background.
* NEW (v1.0.1): Clip mask support to restrict the editable design area.
* Visual overlay frame to clearly indicate the allowed design region.
* The final merged design is exported as PNG and stored with the cart item.
* Design files can be displayed in the admin order screen (per order item).
* Lightweight lightbox support for viewing uploaded images.

This plugin is designed for stores that sell personalized products (e.g., t-shirts, mugs, phone cases, posters).

Clip Mask (New in v1.0.1)

Starting from version 1.0.1, you can optionally upload a clipping mask image per product to limit where customers can place and preview their designs.

Recommended format: PNG
Transparent area = allowed design region
Opaque area = hidden / restricted region
The canvas preview and exported PNG respect the defined clipping boundaries

This helps ensure designs stay within printable areas and improves print accuracy.

Third-party libraries

This plugin bundles Fabric.js for the canvas editor functionality.
Fabric.js is licensed under the MIT License. The Fabric.js license file is included in the plugin package.

Usage

Go to WooCommerce Product Design Upload Settings (wp-admin/admin.php?page=wcpdu-settings) and enable the option to allow customers to upload designs.
Go to Products Edit product.
Enable the design upload option for that product.
(Optional) Upload a Clipping Mask Image to restrict the editable area.
On the product page, click the “Customize” button.
Upload an image, move/scale it within the allowed area, then click “Apply”.
Add to cart. The merged PNG is saved and attached to the cart item and order item meta.