function parseHex(hex) {
                const length = hex.length;
                if (length === 0) {
                    // Invalid color
                    return null;
                }
                if (hex.charCodeAt(0) !== 35 /* CharCode.Hash */) {
                    // Does not begin with a #
                    return null;
                }
                if (length === 7) {
                    // #RRGGBB format
                    const r = 16 * _parseHexDigit(hex.charCodeAt(1)) + _parseHexDigit(hex.charCodeAt(2));
                    const g = 16 * _parseHexDigit(hex.charCodeAt(3)) + _parseHexDigit(hex.charCodeAt(4));
                    const b = 16 * _parseHexDigit(hex.charCodeAt(5)) + _parseHexDigit(hex.charCodeAt(6));
                    return new Color(new RGBA(r, g, b, 1));
                }
                if (length === 9) {
                    // #RRGGBBAA format
                    const r = 16 * _parseHexDigit(hex.charCodeAt(1)) + _parseHexDigit(hex.charCodeAt(2));
                    const g = 16 * _parseHexDigit(hex.charCodeAt(3)) + _parseHexDigit(hex.charCodeAt(4));
                    const b = 16 * _parseHexDigit(hex.charCodeAt(5)) + _parseHexDigit(hex.charCodeAt(6));
                    const a = 16 * _parseHexDigit(hex.charCodeAt(7)) + _parseHexDigit(hex.charCodeAt(8));
                    return new Color(new RGBA(r, g, b, a / 255));
                }
                if (length === 4) {
                    // #RGB format
                    const r = _parseHexDigit(hex.charCodeAt(1));
                    const g = _parseHexDigit(hex.charCodeAt(2));
                    const b = _parseHexDigit(hex.charCodeAt(3));
                    return new Color(new RGBA(16 * r + r, 16 * g + g, 16 * b + b));
                }
                if (length === 5) {
                    // #RGBA format
                    const r = _parseHexDigit(hex.charCodeAt(1));
                    const g = _parseHexDigit(hex.charCodeAt(2));
                    const b = _parseHexDigit(hex.charCodeAt(3));
                    const a = _parseHexDigit(hex.charCodeAt(4));
                    return new Color(new RGBA(16 * r + r, 16 * g + g, 16 * b + b, (16 * a + a) / 255));
                }
                // Invalid color
                return null;
            }
Converts an Hex color value to a Color.
returns r, g, and b are contained in the set [0, 255]
@param hex string (#RGB, #RGBA, #RRGGBB or #RRGGBBAA).