function convhull_test_case ( points, prefix )

%*****************************************************************************80
%
%% convhull_test_case() tests convhull() on a specific set of points.
%
%  Licensing:
%
%    This code is distributed under the MIT license.
%
%  Modified:
%
%    08 March 2022
%
%  Author:
%
%    John Burkardt
%
%  Input:
%
%    real points[n,2]: a set of points whose convex hull is to be computed.
%
%    string prefix: an identifier for the case.
%
  k = convhull ( points(:,1), points(:,2) );
%
%  Plot the convex hull.
%
  clf ( );
  hold ( 'on' );
  plot ( points(:,1), points(:,2), 'b.', 'MarkerSize', 20 );
  plot ( points(k,1), points(k,2), 'r-', 'LineWidth', 2 );
  hold ( 'off' );
  grid ( 'on' );
  axis ( 'tight' );
  axis ( 'equal' );
  xlabel ( '<--- X --->' );
  ylabel ( '<--- Y --->' );
  title ( sprintf ( 'convhull(%s)', prefix ) );
  filename = sprintf ( '%s.png', prefix );
  fprintf ( 1, '  Graphics saved as "%s"\n', filename );
  print ( '-dpng', filename );

  return
end

