in src/libguac/protocol.c [201:228]
int guac_protocol_send_arc(guac_socket* socket, const guac_layer* layer,
int x, int y, int radius, double startAngle, double endAngle,
int negative) {
int ret_val;
guac_socket_instruction_begin(socket);
ret_val =
guac_socket_write_string(socket, "3.arc,")
|| __guac_socket_write_length_int(socket, layer->index)
|| guac_socket_write_string(socket, ",")
|| __guac_socket_write_length_int(socket, x)
|| guac_socket_write_string(socket, ",")
|| __guac_socket_write_length_int(socket, y)
|| guac_socket_write_string(socket, ",")
|| __guac_socket_write_length_int(socket, radius)
|| guac_socket_write_string(socket, ",")
|| __guac_socket_write_length_double(socket, startAngle)
|| guac_socket_write_string(socket, ",")
|| __guac_socket_write_length_double(socket, endAngle)
|| guac_socket_write_string(socket, ",")
|| guac_socket_write_string(socket, negative ? "1.1" : "1.0")
|| guac_socket_write_string(socket, ";");
guac_socket_instruction_end(socket);
return ret_val;
}