voluptasquisquam/src/image/filter/hypotenuse.js

Image processing and manipulation in JavaScript

import {validateArrayOfChannels} from '../../util/channel';
import Image from '../Image';

/**
 * Calculate a new image that is the hypotenuse between the current image and the otherImage.
 * @memberof Image
 * @instance
 * @param {Image} otherImage
 * @param {object} [options={}]
 * @param {number} [options.bitDepth=this.bitDepth]
 * @param {number[]|string[]} [options.channels] : to which channel to apply the filter. By default all but alpha.
 * @return {Image}
 */
export default function hypotenuse(otherImage, options = {}) {
    let {bitDepth = this.bitDepth, channels} = options;
    this.checkProcessable('hypotenuse', {
        bitDepth: [8, 16, 32]
    });
    if (this.width !== otherImage.width || this.height !== otherImage.height) {
        throw new Error('hypotenuse: both images must have the same size');
    }
    if (this.alpha !== otherImage.alpha || this.bitDepth !== otherImage.bitDepth) {
        throw new Error('hypotenuse: both images must have the same alpha and bitDepth');
    }
    if (this.channels !== otherImage.channels) {
        throw new Error('hypotenuse: both images must have the same number of channels');
    }

    let newImage = Image.createFrom(this, {bitDepth: bitDepth});

    channels = validateArrayOfChannels(this, {channels: channels});

    let clamped = newImage.isClamped;

    for (let j = 0; j < channels.length; j++) {
        let c = channels[j];
        for (let i = c; i < this.data.length; i += this.channels) {
            let value = Math.hypot(this.data[i], otherImage.data[i]);
            if (clamped) { // we calculate the clamped result
                newImage.data[i] = Math.min(Math.max(Math.round(value), 0), newImage.maxValue);
            } else {
                newImage.data[i] = value;
            }
        }
    }

    return newImage;
}