HexStamp

HexStamp – Palette-Based Image Recoloring Tool

HexStamp is a fast, lightweight command-line utility for batch recoloring PNG images using a palette extracted from another PNG image.

It’s built for artists, pixel-art creators, and game developers who want a simple, deterministic way to apply a fixed color palette to many images at once—without editors, GUIs, or complex setup.

What HexStamp Does

HexStamp takes:

• One palette image (any PNG)

• One or more input images (PNG)

And for every pixel in every input image:

• Compares its RGBA color to all colors in the selected palette

• Finds the closest match using per-channel deviation (R, G, B, A)

• Replaces the pixel with that palette color

The recolored images are saved as new files, leaving the originals untouched.

Typical Use Cases

• Palette swapping pixel art

• Enforcing a strict color palette across multiple sprites

• Recoloring assets for different factions, themes, or biomes

• Preparing assets for retro or limited-color pipelines

• Batch-processing PNGs without opening an image editor

How to Use (Quick Overview)

1. Put one or more PNG images into the palettes folder
   (each image represents a possible color palette)

2. Put the PNG images you want to recolor into the inputs folder

3. Run HexStamp.exe

4. Choose a palette from the numbered list

5. Find the recolored images in the outputs folder

HexStamp will show live progress for each image and report completion when finished.

Features

• ✔ Batch processing (handles multiple images automatically)

• ✔ Full RGBA support (alpha is preserved and matched if present in palette)

• ✔ Deterministic results (same input + palette = same output)

• ✔ Very fast (color caching + optimized loops)

• ✔ No runtime dependencies

• ✔ Portable single executable (Windows)

Important Notes

• HexStamp works only with PNG files (I might expand this later)

• All pixels in the palette image are considered valid palette colors

• Output images overwrite files with the same name in outputs

• This is a command-line tool, not a GUI application

Included Libraries

HexStamp uses stb_image and stb_image_write by Sean Barrett
(these libraries are public domain / MIT-style licensed).

AI Assistance Disclosure

Parts of HexStamp’s design and implementation were developed with assistance from OpenAI’s ChatGPT.
All final decisions, testing, integration, and distribution were performed by the author
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