Rescale the layer to have given max and min values v5.1.0

Masks and depth-like layers arrive on all sorts of brightness scales, and half the time you need them on a different one. This node is a linear level-stretch: it maps a range of input values (x1–x2) onto a target range (y1–y2) and clips everything outside. Think of it as the "levels" tool from a photo editor, applied to a single-channel layer.

The use case that keeps coming back: a mask that only occupies values 40–200 needs to be full-range for a model that expects 0–255; or you want to squash a depth layer into a narrow band so it reads as a subtle lighting layer. It's a tiny, composable utility - the pack's own recolor and renormalize nodes assume well-distributed inputs, and this is the tool that makes them well-distributed.

How it works

Pure linear remap. The input layer is converted to float, and every pixel goes through:

y = ((x - x1) / (x2 - x1)) * (y2 - y1) + y1

then everything is clipped to [y1, y2]. The node defensively swaps x1/x2 and y1/y2 if you feed them inverted, so a descending range doesn't break - nice touch. If x2 - x1 is zero it adds a tiny epsilon to avoid dividing by zero. The result comes back as a MASK.

It pairs naturally with the pack's tri3d-get_histogram_limits, which computes x1/x2 automatically by walking the layer's histogram and trimming the tails past a threshold_fraction - so you can drive this node's input range from the data instead of eyeballing it.

The inputs that matter

• layer_as_mask (MASK) - the layer to stretch.
• y1 / y2 (INT, 0–255) - the target output range. Defaults are 100 and 200.
• x1 / x2 (INT, 0–255) - the input range you're mapping from (the current spread of your values). Defaults 100 and 200.

Output: rescaled layer as MASK.

Installing it

Same pack:

cd ComfyUI/custom_nodes
git clone https://github.com/TRI3D-LC/tri3d-comfyui-nodes
cd tri3d-comfyui-nodes
pip install -r requirements.txt

or ComfyUI Manager → "tri3d-comfyui-nodes", restart, under TRI3D.

Common issues

• Ignoring the actual input range - the defaults (100–200) are placeholders, not detected values. If your layer's values live elsewhere, the stretch will crush or clip them. Either read the histogram or use get_histogram_limits to feed real numbers.
• Clipping is silent - values below x1 and above x2 get clamped to y1/y2, so heavy stretches lose information. If edges look posterized, widen the input range.
• It stretches linearly only - no gamma, no curves. For a curve-shaped remap you'd want a different node; this one is deliberately dumb.

For a "make this layer live in this range" job, it's the smallest honest tool in the pack - no pretensions, no surprises, and it composes cleanly with the nodes around it.