Draw using an existing figure object/canvas in MATLAB - matlab

Question

I am trying to animate a clock hand's movement using MATLAB. I created 'draw_clock()' program/script in a file named 'draw_clock.m' that goes something like this.
function draw_clock()
set_figure();
draw_clock_hands();
end
function set_figure()
figure;
hold on;
axis off;
title('Clock');
end
Then I have a script file named 'animate_clock.m' that has something like this:
hours = 0:12;
minutes = 0:59;
for i = 1:numel(hours)
for j = 1:numel(minutes)
draw_clock();
pause(0.05);
refresh;
end
end
When I run 'animate_clock.m', new window/clock figure for every frame is opened instead of redrawing on the same canvas/figure. I understand why this is happening because 'set_figure()' is being called every time 'draw_clock()' is called. I'm new to MATLAB, so if there's a way to stop creating new figure with the code skeleton above. I guess if I can detect if there's a figure object already opened, then I can skip calling 'set_figure()' inside 'draw_clock()' next time it is being called?
Thank you in advance for your answers!

Answer 1

So after searching and reading the doc a bit, I think there are a couple of different ways to detect if a matlab figure already exists. One that I found useful (and relatively simple) is to:
- assign the 'Name' property to the figure window
- find if an object with the assigned name exists using 'findobj(...)' method
- if figure already exists, use 'hold on' to reuse the old figure
- else, create a new figure with the name 'figure('Name', 'foo figure')'
For my case, 'set_figure()' method will become something like this:
function set_figure()
fig_name = 'My Clock';
if isempty(findobj('Name', fig_name))
figure('Name', fig_name);
end
hold on;
axis off;
end
Hope someone can come and improve it to become more robust. :)