Save Panel Layout

Save Panel Layout is how you build a library of reusable comic page structures. It takes a layout, renders it as an image, and - here's the trick - embeds the entire layout as text metadata inside that PNG. The image you see is just the preview; the real payload is invisible, and it's exactly what Load Panel Layout reads back later.

That's the part that makes this pack worth learning. A panel layout is an abstract tree of cuts (direction, angle, split positions), and in this pack it's serialized to a compact string like V0_0(H0_0(),H0_0(V15_0(),H0_0())) - a tiny little language of V/H cuts and angles. Save Panel Layout stamps that string into the PNG's cut_tree metadata chunk. The sample layouts folder in the repo is full of these: ordinary-looking PNGs you can drag into ComfyUI and treat as saved layouts. It's the same trick as a workflow image, applied one level down.

Inputs are few:

• layout - a PANEL_LAYOUT from the random/grid generators or Mutate.
• draw_as - flips the drawn image between left-to-right and right-to-left reading. Note the tooltip carefully: the stored data is identical either way. This is purely about how the preview looks, for people who think in manga RTL pages.
• filename_prefix - default "PanelLayout", supports ComfyUI's formatting tokens like %date:yyyy-MM-dd% or %CanvasPanel.width%, so you can organize a real file system out of your page library.

It writes to your ComfyUI output directory with the usual counter suffix (PanelLayout_00001_.png), and it's marked as an output node - that's ComfyUI's way of saying this is a terminal node that also shows its result in the UI.

Where this shines: you generate a page layout, tweak it, save it, and never have to reconstruct it from a screenshot or a seed again. Later you can reload the PNG, mutate it, and save the variant as a new file - a whole chapter of page skeletons accumulating as a folder of small images. The alternative - treating layouts as throwaway and re-rolling every time - is how you end up with every page looking like the same grid.

One real gotcha: since the layout lives in the metadata, don't re-encode the PNG through tools that strip metadata (screenshots, most image editors, social-media uploads). The preview image survives; the layout usually doesn't. If you ever load a PNG and Load Panel Layout errors out complaining there's no cut_tree metadata, that's exactly what happened.

Installing

Part of comfyui-panels by bmad4ever. Install via ComfyUI Manager (search "comfyui-panels") and restart, or clone it yourself:

cd ComfyUI/custom_nodes
git clone https://github.com/bmad4ever/comfyui_panels

The pack needs shapely, matplotlib, and opencv-python - no model files, no GPU. Shapely is pinned to an exact version, so a version conflict with another pack is the realistic failure mode if nodes don't load.