voluptasquisquam/src/util/kernel.js

Image processing and manipulation in JavaScript

import isInteger from 'is-integer';

export function validateKernel(kernel) {
    let kHeight, kWidth;
    if (Array.isArray(kernel)) {
        if (Array.isArray(kernel[0])) { // 2D array
            if (((kernel.length & 1) === 0) || ((kernel[0].length & 1) === 0)) {
                throw new RangeError('validateKernel: Kernel rows and columns should be odd numbers');
            } else {
                kHeight = Math.floor(kernel.length / 2);
                kWidth = Math.floor(kernel[0].length / 2);
            }
        } else {
            let kernelWidth = Math.sqrt(kernel.length);
            if (isInteger(kernelWidth)) {
                kWidth = kHeight = Math.floor(Math.sqrt(kernel.length) / 2);
            } else {
                throw new RangeError('validateKernel: Kernel array should be a square');
            }
            // we convert the array to a matrix
            let newKernel = new Array(kernelWidth);
            for (let i = 0; i < kernelWidth; i++) {
                newKernel[i] = new Array(kernelWidth);
                for (let j = 0; j < kernelWidth; j++) {
                    newKernel[i][j] = kernel[i * kernelWidth + j];
                }
            }
            kernel = newKernel;

        }
    } else {
        throw new Error('validateKernel: Invalid Kernel: ' + kernel);
    }
    return {kernel, kWidth, kHeight};
}