Ideogram 4 Prompt Builder Pro - Preview BG Update

This node has exactly one job, and the name says it: take an image from your workflow and stick it behind the canvas of the Ideogram 4 Prompt Builder Pro, so you can draw your boxes on top of it. No API, no weights, no settings - it's the two-socket helper that turns a prompt builder into a trace tool.

Why bother? Ideogram 4's whole deal is regional control: you draw bounding boxes, each becomes an element in the JSON caption, and the model renders that layout. But drawing boxes on a blank black canvas is guesswork. The workable workflow is to first generate (or load) a base image - a character reference, a rough composition, a hand-made layout sketch - then feed it through this node and literally place your text and object boxes over the shapes that are already there. It's the difference between composing blind and composing against a target.

How it works

The mechanism is gloriously simple. Wire the builder's guid output into this node's guid input and connect any image to image, run the graph, and the node writes the image to ComfyUI's temp folder as byae_ideogram_bg_{guid}.png, then sends a websocket message. The builder's editor polls for that file and updates its canvas background automatically. The background_opacity slider on the builder node (default 0.5) blends it over black - 0 hides it, 1 shows it at full strength.

It has no outputs at all. It's an output node; the "result" is the file sitting in temp and the editor updating live.

Wiring it up

Just two inputs, both required:

• image - the image to use as the canvas background. Any IMAGE tensor: a generated frame, a loaded reference, an upscale.
• guid - the string coming out of the builder's guid socket. This is what ties the background to your editor instance, so the poll knows which file to read.

Chain it right after the node that produces your reference, run once, and the canvas should refresh. It also works live: regenerate the upstream image and the background updates on the next run.

Installing it

Same pack as the builder, so you get both at once. ComfyUI Manager, search ComfyUI-ByAE-IdeogramTools, or:

cd ComfyUI/custom_nodes
git clone https://github.com/by-ae/ComfyUI-ByAE-IdeogramTools.git

Restart ComfyUI. No requirements.txt, no KJNodes, no model downloads from the pack - the only prerequisite is the Ideogram 4 checkpoint you're already using.

Common issues

The failure mode to know: guid is validated as a UUID, and an empty or malformed one makes the node silently skip writing the file - so if the canvas never updates, check that the builder's guid output is actually connected. The background lives in the ComfyUI temp directory, which gets cleared on a fresh server start, so an old workflow resumed after a restart may need one re-run to repopulate it. And remember this is a canvas reference, not a final preview - the boxes and the reference won't match pixel-perfectly, and the model, not the node, is what decides how literally it follows your tracing.