Quick Shape Mask 🕒🅡🅣🅝

A mask of a circle or square shouldn't need a 200ms Python journey, and in most packs it does anyway. Quick Shape Mask is the version built for the one constraint this pack cares about: it has to run every frame in a real-time loop. So instead of going through PIL's full drawing stack, it builds the mask with straight NumPy array operations - and it's genuinely fast, which is the whole point of its existence.

You get two shapes: circle and square. width and height define the shape's size in pixels, x and y place its center on a canvas of canvas_width × canvas_height, and batch_size duplicates the mask N times (so you can feed a batch without re-running the node). For the circle it computes a per-pixel distance check with np.ogrid - an axis-aligned ellipse, really, so width/height different from each other gives you an oval. For the square it's a simple slice fill. Either way you get a hard-edged MASK in the 0–1 range, one pixel wide borders and all.

The real-time angle makes it more useful than it first looks. Because you can drive x, y, width, and height from the pack's control nodes - a Float Control sweeping the radius, motion mapping the position - you can animate a mask live without any image processing. It's also the fastest way to build an ROI: this pack's ROINode takes a mask to define a region of interest, and Quick Shape Mask hands you a clean one to feed it.

The inputs that matter

• shape - circle or square.
• width / height - the shape's size in pixels (they're the ellipse axes for circles).
• x / y - center position on the canvas, in pixels from the top-left.
• canvas_width / canvas_height - output canvas size. These define the mask resolution.
• batch_size - copies of the same mask; default 1.

Output: one MASK (BHW format, so one channel).

Install & gotchas

In ryanontheinside/ComfyUI_RealtimeNodes - ComfyUI Manager (search "Control Nodes") or:

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

Two things to keep straight. The shape's x/y is its center, not its corner - a 64px circle at 0,0 will be partially off-canvas, and the node just clips it. And the defaults are quirky: the shape defaults to 64×64 but the canvas to 512×512, centered at 256,256 - so the default is a small circle mid-canvas, which is usually not what you want on first drop. Set the size and position and you're good. Also remember the edges are razor hard; if your inpaint or composite wants softness, a blur after this node is your friend. For the cost of a couple of numpy ops per frame, it's the cheap way to put a shape anywhere, anytime.