How to draw arc shape in Processing

draw_arc.pde

void drawArc(int center_x, int center_y, float start_a, float finish_a, float inner_radius, float outer_radius) {
  fill(color(0, 0, 0));

  float angle_delta = finish_a - start_a;
  int pass_length = 1;
  int pass_number = 0;
  float angular_step = 0;
  float cur_x = 0;
  float cur_y = 0;
  float current_angle = 0;
  float arc_length = 0;

  beginShape();

  angular_step = 2 * asin(pass_length/inner_radius/2);
  arc_length = angle_delta * inner_radius;
  pass_number = (int)(arc_length / pass_length);
  current_angle = start_a;
  for (int i=0; i<pass_number; i++) {
    cur_x = center_x + (cos(current_angle) * inner_radius);
    cur_y = center_y + (sin(current_angle) * inner_radius);
    vertex((int) cur_x, (int) cur_y);
    current_angle += angular_step;
  }

  angular_step = 2 * asin(pass_length/outer_radius/2);
  arc_length = angle_delta * outer_radius;
  pass_number = (int)(arc_length / pass_length);
  current_angle = finish_a;
  for (int i=0; i<pass_number; i++) {
    cur_x = center_x + (cos(current_angle) * outer_radius);
    cur_y = center_y + (sin(current_angle) * outer_radius);
    vertex((int) cur_x, (int) cur_y);
    current_angle -= angular_step;
  }

  endShape(CLOSE);
}