cycloid.m

%% Matlabe example 
%%Animated cycloid curve

teta1 = 0:1:120/3-2;
a=0:0.01:2*pi;
ca=0:0.01:2*pi;

%first frame
R=10;
al = (pi/3+pi/20);
x0 = al*R;
ang = al*180/pi;

figure('Color', 'white')
grp = plot(R*(a-sin(a)), R*(1-cos(a)), 'LineWidth', 2, 'Color', 'b')
hold
grid
circle = plot(R*sin(a)+x0, R*cos(a)+10, 'LineWidth', 2, 'Color', 'r')
xM = R*(al-sin(al));
yM = R*(1-cos(al));
l3 = plot([xM x0],[yM R], 'LineWidth', 2, 'Color', 'r')
dot = plot(xM,yM, '*')
ht = title(sprintf('Angle: %i', ang));

axis equal

% Get figure size
pos = get(gcf, 'Position');
width = pos(3);
height = pos(4);

% Preallocate data (for storing frame data)
mov = zeros(height, width, 1, length(teta1), 'uint8');

for i = 1:length(teta1)
  al = (pi/3+pi/20)+pi/20*i;
  a=al-pi:0.01:al+pi;
  xM = R*(al-sin(al));
  yM = R*(1-cos(al));
  x0 = al*R;
  cX = R*sin(ca)+x0;
  cY = R*cos(ca)+10;
  ang = al*180/pi;
  
  set(grp, 'XData', R*(a-sin(a)), 'YData',  R*(1-cos(a)))
  set(circle, 'XData', cX, 'YData', cY)
  set(l3, 'XData', [xM x0], 'YData', [yM R])
  set(dot, 'XData', xM, 'YData', yM)
  
  set(ht, 'String', sprintf('Angle: %0.f', ang))
  
  % Get frame as an image
  f = getframe(gcf);
  % Create a colormap for the first frame. For the rest of the frames,
  % use the same colormap
  if i == 1
    [mov(:,:,1,i), map] = rgb2ind(f.cdata, 256, 'nodither');
  else
    mov(:,:,1,i) = rgb2ind(f.cdata, map, 'nodither');
  end
end

% Create animated GIF
imwrite(mov, map, 'animation.gif', 'DelayTime', 0, 'LoopCount', inf)