voluptasquisquam/src/image/operator/__tests__/getSeparatedKernel.js

Image processing and manipulation in JavaScript

import getSeparatedKernel from '../getSeparatedKernel';

describe('getSeparatedKernel', () => {
    it('should return null if not separable', () => {
        expect(getSeparatedKernel([[3, 1, 2], [4, 5, 9], [6, 8, 10]])).toEqual(null);
    });

    it('should return an array of kernel components', () => {
        verify([[1, 2, 1]]);
        verify([[0, 2, 1]]);
        verify([
            [1, 0, -1],
            [2, 0, -2],
            [1, 0, -1]
        ]);
    });
});

function verify(kernel) {
    const [v, h] = getSeparatedKernel(kernel);
    expect(v.length).toEqual(kernel.length);
    expect(h.length).toEqual(kernel[0].length);
    for (let i = 0; i < v.length; i++) {
        for (let j = 0; j < h.length; j++) {
            expect(v[i] * h[j]).toBeCloseTo(kernel[i][j], Number.EPSILON);
        }
    }
}