Line Animations

This example shows how to create an animation of two growing lines. The animatedline function helps you to optimize line animations. It allows you to add new points to a line without redefining existing points.

Create Lines and Add Points

Create two animated lines of different colors. Then, add points to the lines in a loop. Set the axis limits before the loop so that to avoid recalculating the limits each time through the loop. Use a drawnow or drawnow limitrate command to display the updates on the screen after adding the new points.

a1 = animatedline('Color',[0 .7 .7]);
a2 = animatedline('Color',[0 .5 .5]);

axis([0 20 -1 1])
x = linspace(0,20,10000);
for k = 1:length(x)
    % first line
    xk = x(k);
    ysin = sin(xk);
    addpoints(a1,xk,ysin);

    % second line
    ycos = cos(xk);
    addpoints(a2,xk,ycos);

    % update screen
    drawnow limitrate
end

The animation shows two lines that grow as they accumulate data.

Query Points of Line

Query the points of the first animated line.

[x,y] = getpoints(a1);

x and y are vectors that contain the values defining the points of the sine wave.