Helper to fit a given size into another, preserving aspect ratio

size-helper.js

'use strict';

/**
 * @exports sizeFactory
 * @private
 *
 * @param {{width: number, height: number}} size
 * @returns {sizeHelper}
 */
function sizeFactory(size) {
    var ratio = size.width / size.height;

    /**
     * Helpers for fitting a game into a specific size.
     * This is used for the property 'size' on the object returned from a nolimit.info() call.
     * @exports sizeHelper
     */
    var sizeHelper = {

        width: size.width,

        height: size.height,

        ratio: ratio,

        /**
         * Given a width and height, return a new size that fits into that and preserves the orginal aspect ratio.
         *
         * @param width
         * @param height
         * @returns {sizeHelper} The new size object
         *
         */
        fit: function(width, height) {
            return width / height < ratio ? this.fitWidth(width) : this.fitHeight(height);
        },

        /**
         * Given a width only, return a new size that fits into that and preserves the orginal aspect ratio.
         *
         * @param width
         * @returns {sizeHelper} The new size object
         */
        fitWidth: function(width) {
            return sizeFactory({
                width: width,
                height: Math.round(width / ratio)
            });
        },

        /**
         * Given a height only, return a new size that fits into that and preserves the orginal aspect ratio.
         *
         * @param height
         * @returns {sizeHelper} The new size object
         */
        fitHeight: function(height) {
            return sizeFactory({
                width: Math.round(height * ratio),
                height: height
            });
        }
    };
    return sizeHelper;
}

module.exports = sizeFactory;