C2PM(Color to Pixel Map)

C2PM (Color-to-Pixel Map) is a new image representation format developed by Yukesh J. It stores image data using an inverted index structure rather than traditional pixel-linear ordering.

In C2PM, each unique RGB color is stored once, followed by a list of all pixel positions where that color appears. Formally, the format maps:

Color → {Pixel Indices}

This structure enables several properties:

Design Characteristics

Lossless representation of exact RGB images

Direct access to all pixels of a given color without scanning the entire image

Deterministic binary layout (header + entries + index arrays)

Simple linear decoding algorithm suitable for tooling or analysis

Potential Applications

Pixel-art workflows

Palette-based editing systems

Color-region mask generation

Image segmentation and inverse indexing research

Developer tooling that benefits from color-centric access patterns

Current Scope

C2PM is not a replacement for existing compressed formats (PNG, JPEG) and is not optimized for general photography or real-time rendering. It is intended as an alternative representation model focused on color organization rather than storage minimization.

Specification & Implementation

A reference implementation (encoder + decoder in C) and a description of the binary layout are available here:

https://github.com/yukeshj2006/C2PM-Color-to-Pixel-Map-Image-Format

Feedback on structural design, potential optimizations, or use-cases is welcome.