chromajs

Chroma.js, often written chroma.js or chroma-js, is a JavaScript library that provides color manipulation and color scale utilities for web development and data visualization. It offers color parsing, conversion between color spaces, and interpolation to generate smooth gradients.

Input formats include hex, RGB(A), HSL(A), and named colors; outputs can be requested in several representations. A distinguishing feature is perceptual color interpolation using spaces like Lab or LCh, which yields more natural transitions than naive RGB interpolation. It also provides ready-to-use color scales and palettes that cover sequential, diverging, and qualitative schemes, suitable for mapping numeric data to colors.

Usage is lightweight and cross-environment: it runs in browsers and in Node.js. The API centers on a color factory that can be extended into scale utilities; developers often integrate chroma.js with visualization libraries such as D3 or Canvas drawing routines.

Chroma.js is maintained as an open-source project with contributions from a community of developers. It is widely used in tutorials and data-visualization projects for its straightforward API and robust color operations.