ImageDrawRectangleRoundedByContainer

Imagine the workflow: you generate a portrait, cut out the subject, and now you want a soft rounded card behind them at exactly the canvas size, so you can drop a caption or a watermark on top. Typing the pixel dimensions by hand works until you change resolution and the layout silently breaks. ImageDrawRectangleRoundedByContainer is the version of the rounded-rect that sidesteps that entirely - instead of width/height, you feed it a reference image and it sizes the canvas to match.

How it works

Mechanically it's the same drawing pipeline as ImageDrawRectangleRounded, just with the size inputs replaced by a container IMAGE input. The node reads the container's dimensions and draws a rounded rectangle onto a transparent RGBA canvas of that exact size using PIL's rounded_rectangle. Coordinates are normalized 0–1 fractions - start_x, start_y, end_x, end_y - so the box scales proportionally with whatever you feed in. You get radius (0–360) for corner roundness plus the four corner toggles (top_left_corner, top_right_corner, bottom_right_corner, bottom_left_corner) that let you round just the top, just the bottom, or any combination.

Anti-aliasing comes from SSAA (default 4): the rectangle is drawn at 4× the target size, then downsampled with your chosen method - lanczos is the quality default, nearest if you want crisp pixel edges. fill_red/green/blue + fill_alpha set the body, outline_red/green/blue, outline_alpha, and outline_size set the stroke.

Inputs that matter

• container - any IMAGE; its dimensions become the canvas. This is the whole point of the node.
• start_x / start_y / end_x / end_y - box position as 0–1 fractions of the container.
• radius and the four *_corner toggles - corner shaping.
• SSAA and method - anti-aliasing vs. speed.

It outputs a single IMAGE. Remember it's transparent outside the rectangle, so the intended path is container → this node → composite the rectangle (and whatever sits on it) over the original image.

Installing it

One install covers the whole Allor pack:

cd ComfyUI/custom_nodes
git clone https://github.com/Nourepide/ComfyUI-Allor

Then restart ComfyUI (or use ComfyUI Manager and search for Allor Plugin). First boot creates the plugin's config.json and installs rembg + onnx from requirements.txt - expect a slow first start. No model files are needed for this node.

Gotchas

• Allor's repo was rebased to strip images from history, so old clones can break on git pull or auto-update. If update fails, delete and re-clone; the README links to the official troubleshooting docs.
• Don't feed a multi-frame batch and expect one rectangle per frame - the node sizes off container[0], the first frame.
• Transparent output again: composite, don't save-and-admire.

For a plain (non-rounded) box sized to a reference image, use ImageDrawRectangleByContainer; for a rounded box on a fresh canvas, use ImageDrawRectangleRounded.