sharp-vibrant/src/image/base.ts

Extract prominent colors from an image in a node environment using sharp.

import type {
  Filter, Image, ImageData, ImageSource, ComputedOptions,
} from '../typing';

abstract class ImageBase implements Image {
  abstract load(image: ImageSource, opts: ComputedOptions): Promise<ImageBase>;

  abstract readonly pixelCount: number;

  abstract readonly imageData: ImageData;

  abstract readonly width: number;

  abstract readonly height: number;

  abstract cleanup(): void;

  applyFilter(filter: Filter): Promise<ImageData> {
    const { imageData } = this;

    if (typeof filter === 'function') {
      const pixels = imageData.data;
      const n = pixels.length / 4;
      let offset;
      let r;
      let g;
      let b;
      let a;

      for (let i = 0; i < n; i += 1) {
        offset = i * 4;
        r = pixels[offset + 0];
        g = pixels[offset + 1];
        b = pixels[offset + 2];
        a = pixels[offset + 3];
        // Mark ignored color
        if (!filter(r, g, b, a)) pixels[offset + 3] = 0;
      }
    }

    return Promise.resolve(imageData);
  }
}

export default ImageBase;