yahoo/pngjs-image

// Copyright 2014-2015 Yahoo! Inc.
// Copyrights licensed under the Mit License. See the accompanying LICENSE file for terms.

/**
 * Luminosity filter
 *
 * @method luminosity filter
 * @param {PNGImage} source
 * @param {PNGImage} destination
 * @param {object} options
 * @private
 */
module.exports = function (source, destination, options) {

    var dim = source.getWidth() * source.getHeight(),
        idx,
        value;

    for (idx = 0; idx < dim; idx++) {
        value = source.getLuminosityAtIndex(idx);

        destination.setRed(idx, value);
        destination.setGreen(idx, value);
        destination.setBlue(idx, value);
        destination.setAlpha(idx, source.getAlpha(idx));
    }
};