🧩 Isulion QRCode Generator

The name is a small lie, in a good way: 🧩 IsulionQRCode is a QR code generator that calls no API and needs no key. Type some text or a URL, and it hands you a real, scannable QR code as an IMAGE tensor, ready to stamp onto your generated pictures with the pack's Overlay node. It's one of the few things in the Isulion pack that isn't a prompt generator at all - it's a utility that just works.

If you've ever needed a scannable code on an AI image - a watermark with your handle, a link on a product shot, a code on a flyer - this is the local, dependency-free way to do it.

How it works

Under the hood it uses a bundled, pure-Python QR encoder (Nayuki's qrcodegen.py, shipped inside the pack - no pip installs). It encodes your text into a QR matrix at your chosen error-correction level, then draws it as an image with your colors and scale. The optional logo path resizes your logo image and composites it dead-center with alpha compositing. Everything is numpy and torch, both already in ComfyUI.

The inputs that matter

• text - what the code contains. Defaults to the author's Civitai page, so change it. Multiline is on, but keep it short-ish: QR capacity is real.
• error_correction - L, M, Q, or H (default H, the highest). More redundancy = bigger code but survives damage. If you're adding a logo, stay at H - the source code literally warns that low error correction plus a logo can break scannability.
• scale (default 10) and border (default 4) - module size and quiet-zone width. Defaults are fine; border 4 is the spec minimum.
• foreground_color / background_color - hex strings, defaults black on white.
• transparent_background - makes the background transparent (RGBA output) instead of your background color.
• logo (optional IMAGE), logo_scale_percent (default 23), clear_behind_logo (default true) - drop any image in and it gets centered on the code.

Output

A single IMAGE (RGB, or RGBA if transparent background is on) - the finished QR code.

Installing it

One pack, all Isulion nodes:

1. ComfyUI Manager → Custom Nodes Manager → search Isulion → Install → Restart.
2. Or clone it manually:

cd "your_ComfyUI_install_dir/custom_nodes"
git clone https://github.com/Isulion/ComfyUI_Isulion

No requirements.txt, no models, no keys. The QR encoder is bundled in the pack.

Common issues

Three gotchas. First, transparency: if you turn on transparent background, ComfyUI's in-canvas preview often won't show the alpha, and the node itself notes it. Save as PNG with a SaveImage node and verify there - and remember that previewing on a white canvas hides transparent codes entirely. Second, text length: QR codes have hard capacity limits, and the node returns a blank placeholder image if your text is too long to encode at the chosen error-correction level. Short URLs are fine; a paragraph is not - lower the error correction if you must pack more in. Third, logo scannability: keep the logo under about a third of the code (the default 23% is sane) and leave error correction at H. A code that looks perfect but won't scan is worse than no code.