img_effect_CircleWarp

Filed straight under the pack's own Deprecated category, along with the other three img_effect_* distortion nodes (Liquify, Stretch, WaveWarp). All four are still present and functional in the pack - old workflows won't break - but the author isn't actively developing them further, so if you're picking a warp effect from scratch, treat this as legacy rather than the current recommendation. There's no successor node named in this pack's schema for the effect category specifically, so if you need this exact fisheye/pinch look, this is still the node - just go in knowing it's not getting new features.

What it does

A localized radial distortion around a point you choose - pull pixels toward the center (a pinch) or push them outward (a bulge/fisheye), depending on the sign of strength. It's the same family of effect as Photoshop's Spherize or a lens-distortion filter, applied as a standalone image operation rather than a camera simulation.

The inputs and outputs that matter

• image (required) - what you're warping.
• strength (FLOAT, -2 to 2, default 1) - direction and intensity. Positive values push outward from the center (bulge/fisheye); negative values pull inward (pinch). 0 is a no-op.
• radius (FLOAT, 0.01–1, default 0.5) - how far the effect reaches from the center, as a fraction of the image size. Small values keep the distortion tight and local; values near 1 pull the whole frame in.
• center_x / center_y (FLOAT, 0–1, default 0.5 each) - where the warp is centered, normalized to the image dimensions. 0.5/0.5 is dead center.

One output: IMAGE, the warped result.

How to install it

ComfyUI Manager: search ComfyUI-Apt_Preset, install, restart. Manual:

cd ComfyUI/custom_nodes
git clone https://github.com/cardenluo/ComfyUI-Apt_Preset
pip install -r requirements.txt

install.bat is Windows-only; on Linux (comfy.icu's executor included) run pip install -r requirements.txt directly. No model downloads - this is a pure pixel-remapping effect, and its dependencies are covered by the pack's general requirements.txt (which includes opencv-python-headless and scipy, the kind of libraries a radial warp like this typically leans on).

Common issues

Because the effect is centered and radius-bound rather than covering the whole frame automatically, the most common "nothing happened" report is actually radius set too small relative to where your subject sits, or center_x/center_y pointed at empty background instead of the subject you meant to warp. Nudge the center toward your subject and increase radius gradually rather than assuming the node is broken.

Strength near the extremes (close to ±2) can push pixels far enough that you get visible stretching artifacts or empty/repeated edge pixels near the warp boundary, especially at higher radius - if the result looks broken rather than distorted, back the strength off before troubleshooting anything else.

Being deprecated, this node also isn't the place to expect fixes if you do find an edge case - since there's no announced replacement for this specific effect in the current schema, your options if it doesn't do what you need are to tune the three parameters harder or build the warp with a different pack's effect nodes.

Standard pack-wide note: ComfyUI-Apt_Preset is a large suite, and a fresh install pulls in its full requirements.txt (onnxruntime, gguf, transparent-background, and more, for the other 100+ nodes) - there's a documented case of that failing to import. If the pack throws IMPORT FAILED, check the ComfyUI console for the real missing-package error above the generic message.