Panel Compositor (PanelComposer)

This is the payoff node of ComfyUI-PanelComposer. Panel Layout Provider decides the page geometry, you generate each panel separately, and Panel Compositor does the part everyone used to do by hand in Photoshop or Clip Studio: laying every panel image into its shape on the page, carving the gutters, and handing you one finished page_image. If the pack is a comic factory, this is the assembly line at the end.

The workflow shape is: Panel Layout Provider → per-panel dimensions → generate each panel with your own sampler chain → wire every panel image (in order!) into Panel Compositor along with the same layout_json → out comes the page. The compositor performs no generation of its own - all the geometry comes from layout_json, which is why the two nodes stay in lockstep.

How it works

Two details matter here. First, the images input is a list of independently-sized image tensors, not a single batched IMAGE. That's deliberate: ComfyUI's native IMAGE batching requires uniform height and width, and your panels will never be uniform. The node opts into list-mode input so each panel can be any size. Second, each image is fitted to its panel's bounding box, then masked to the actual polygon shape, and the gutter is carved by eroding that mask - so the gap between panels is real negative space, not just background showing through.

Extra images beyond the panel count get dropped by position; missing ones render as a numbered placeholder swatch in the same palette the Layout Provider preview uses, so a partial page still shows the full layout. That's a feature - you can eyeball panel 4 while panels 1-3 regenerate.

The inputs that matter

• layout_json - the layout string straight out of Panel Layout Provider.
• images - your generated panel images, in the same order as the layout's panels. Order is everything.
• fit_mode - how each image fills its panel, and the setting you'll actually fiddle with. The author's own tooltip is the best summary: cover fills the panel and crops overflow; contain fits inside and pads the rest; stretch fills the box exactly and ignores aspect ratio; fit_to_shape warps the image to match non-rectangular panels.
• scale_algo - the resampling filter for any resizing. lanczos by default, which is right.
• gutter_px (default 6) and gutter_color (default #000000) - the width and color of the gaps between panels. gutter_color also fills whatever padding contain leaves behind, so on a light page you'll want to change it from black.
• canvas_mode - auto (the default) uses the layout's own canvas size from layout_json, so the two nodes can't silently disagree about the page. The other modes - fixed_preset, fixed_custom, and scale_to_input - set the canvas independently, with scale_to_input deriving it from your actual input images (largest or smallest).

On fit_to_shape, and where the gotcha lives

cover, contain, and stretch all fill the panel's rectangular bounding box and then crop away whatever doesn't belong to the panel's actual shape. On a plain rectangle that's invisible. On angled panels - wedges, diagonals, notches - the angled edge slices through a rectangle-fitted image, cutting part of it off. fit_to_shape instead warps the whole image so its corners and edges land on the panel's actual polygon vertices, so nothing gets sliced. It's the reason the pack supports non-rectangular layouts at all, and it's flagged experimental: the README only verifies it against the built-in presets. On a hand-drawn custom shape, check the result - the warping can get weird with concave panels.

How to install it

cd ComfyUI/custom_nodes
git clone https://github.com/INuBq8/ComfyUI-PanelComposer

Restart ComfyUI. ComfyUI Manager users: search "PanelComposer". No extra dependencies beyond Pillow (ComfyUI ships it), no model downloads, no API keys.

Common issues

The one that will bite you first is image order. The compositor matches images to panels by position, not by content - if you generated with right_to_left reading order and feed the images left-to-right, your finished page reads backwards. (A reversed-image gotcha the pack doesn't save you from: you may need to reorder inputs yourself for RTL.) Second, a black gutter_color with contain padding on a white comic page looks jarring - set both deliberately. And if layout_json ever fails to parse, the error message will tell you it's missing required fields or has a malformed polygon, which usually means the layout string got mangled in transit rather than anything wrong with your images.