save_png

function save_png(fig, filename_png)
    % save_png - figure 창을 PNG 파일로 저장
    % fig - figure 창의 핸들
    % filename_png - PNG 파일의 파일명

    screen_dpi = get(0, "ScreenPixelsPerInch");
    screen_pixels = get(0, "ScreenSize");  % [x y w h] in pixels

    screen_x = screen_pixels(1);
    screen_y = screen_pixels(2);
    screen_w = screen_pixels(3);
    screen_h = screen_pixels(4);

    screen_w_in = screen_w / screen_dpi;
    screen_h_in = screen_h / screen_dpi;

    pos_pixel = get(fig, "Position");

    window_x_pix = pos_pixel(1);
    window_y_pix = pos_pixel(2);
    window_w_pix = pos_pixel(3);
    window_h_pix = pos_pixel(4);

    window_dpi = 100.0;

    w_in = window_w_pix / window_dpi;
    h_in = window_h_pix / window_dpi;

    l_in = (screen_w_in - w_in) / 2.0;
    b_in = (screen_h_in - h_in) / 2.0;

    pos_in = [l_in b_in w_in h_in];  # [x y w h] in inches

    figure(fig, "units", "inches", "position", pos_in);

    print(fig, filename_png, "-dpng", "-r100");

    figure(fig, "units", "pixels", "position", pos_pixel);

end