konva/lib/filters/Brightness.js

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

import { _registerCSSFilterFallback } from "../Node.js";
// The shared brightness accessor is registered by Brighten.
import "./Brighten.js";
/**
 * Brightness Filter.
 * CSS-compatible brightness multiplier. An unset brightness leaves pixels unchanged.
 * @function
 * @memberof Konva.Filters
 * @param {Object} imageData
 * @example
 * node.cache();
 * node.filters([Konva.Filters.Brightness]);
 * node.brightness(1.5); // 50% brighter (CSS-compatible)
 */
export const Brightness = function (imageData) {
    brighten(imageData, this.attrs.brightness === undefined ? 1 : this.brightness());
};
// CSS brightness(v) is the same multiplier.
_registerCSSFilterFallback('brightness', brighten);
function brighten(imageData, brightness) {
    const data = imageData.data, len = data.length;
    for (let i = 0; i < len; i += 4) {
        // red
        data[i] = Math.min(255, data[i] * brightness);
        // green
        data[i + 1] = Math.min(255, data[i + 1] * brightness);
        // blue
        data[i + 2] = Math.min(255, data[i + 2] * brightness);
    }
}