konva/lib/filters/Noise.js

HTML5 2d canvas library for interactive graphics, design editors, whiteboards, and diagrams.

import { Factory } from "../Factory.js";
import { Node } from "../Node.js";
import { getNumberValidator } from "../Validators.js";
/**
 * Noise Filter. Randomly adds or substracts to the color channels
 * @function
 * @name Noise
 * @memberof Konva.Filters
 * @param {Object} imageData
 * @author ippo615
 * @example
 * node.cache();
 * node.filters([Konva.Filters.Noise]);
 * node.noise(0.8);
 */
export const Noise = function (imageData) {
    const amount = this.noise() * 255, data = imageData.data, nPixels = data.length, half = amount / 2;
    for (let i = 0; i < nPixels; i += 4) {
        data[i + 0] += half - 2 * half * Math.random();
        data[i + 1] += half - 2 * half * Math.random();
        data[i + 2] += half - 2 * half * Math.random();
    }
};
Factory.addGetterSetter(Node, 'noise', 0.2, getNumberValidator(), Factory.afterSetFilter);
/**
 * get/set noise amount.  Must be a value between 0 and 1. Use with {@link Konva.Filters.Noise} filter.
 * @name Konva.Node#noise
 * @method
 * @param {Number} noise
 * @returns {Number}
 */