# MATLAB Language Drawing Fast drawing

## Example

There are three main ways to do sequential plot or animations: `plot(x,y)`, `set(h , 'XData' , y, 'YData' , y)` and `animatedline`. If you want your animation to be smooth, you need efficient drawing, and the three methods are not equivalent.

``````% Plot a sin with increasing phase shift in 500 steps
x = linspace(0 , 2*pi , 100);

figure
tic
for thetha = linspace(0 , 10*pi , 500)
y = sin(x + thetha);
plot(x,y)
drawnow
end
toc
``````

I get `5.278172 seconds`. The plot function basically deletes and recreates the line object each time. A more efficient way to update a plot is to use the `XData` and `YData` properties of the `Line` object.

``````tic
h = [];   % Handle of line object
for thetha = linspace(0 , 10*pi , 500)
y = sin(x + thetha);

if isempty(h)
% If Line still does not exist, create it
h = plot(x,y);
else
% If Line exists, update it
set(h , 'YData' , y)
end
drawnow
end
toc
``````

Now I get `2.741996 seconds`, much better!

`animatedline` is a relatively new function, introduced in 2014b. Let's see how it fares:

``````tic
h = animatedline;
for thetha = linspace(0 , 10*pi , 500)
y = sin(x + thetha);
clearpoints(h)
`3.360569 seconds`, not as good as updating an existing plot, but still better than `plot(x,y)`.
Of course, if you have to plot a single line, like in this example, the three methods are almost equivalent and give smooth animations. But if you have more complex plots, updating existing `Line` objects will make a difference. PDF - Download MATLAB Language for free