Code's improvement (plots animation)

Question

Julián Francisco 2011-6-3

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/8756-code-s-improvement-plots-animation

Hi. My intention is creating an animated plot which will represent the trajectory of a body in the space. I have written this code for it. My problem is more simple that it appears. I want to see the movie (the animated plot stored) in the active figure window but I can not. When I maximize the window, I realize it is empty i.e. the movie is not contained.

t = 0:pi/50:10*pi;
x = sin(t);
y = cos(t);
z = t;
xmin = min(x);
ymin = min(y);
zmin = min(z);
xmax = max(x);
ymax = max(y);
zmax = max(z);
fh = figure;
ah = axes('Parent',fh);
N = 101;
for i = uint8(1):uint8(N+1)
delta = (10*pi)/N;
b = delta*(double(i-1));
t = 0:0.01:b;
plot3(ah,sin(t),cos(t),t);
set(ah, 'XLim', [xmin xmax],'YLim', [ymin ymax],'Zlim',[zmin zmax]);
axis square;
pause(0.008);
M(i) = getframe(gcf);
end
cla;
movie(fh,M,1);

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Answer 1

Jonas Reber 2011-6-3

1
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https://ww2.mathworks.cn/matlabcentral/answers/8756-code-s-improvement-plots-animation#answer_12082

the problem is that getframe as used by you gets the current figure as it is. If you maximize the window and "record" the movie maximized, you will get a maximized movie.

you could change getframe(gcf) to getframe(gca) to only retrieve the axis. but this still takes the axes as it is when recording.

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Jonas Reber 2011-6-4

you have to think of the function "getframe" as a "printscreen" function which takes an image of your screen (a selected rectangle - notice that you can even define a rectangle with getframe) as you see it at that very moment (that's why it doesn't work when the screensaver is on).

if you now let getframe get a picture of your figure it is basically the same as if you would manually do such a printscreen of your figure window. what happens if you do a printscreen is that you get an image of the size of your screen resolution. getframe basically gets you an image of the size of your handle (axes, figure, ...).

If you then play back this image in a different (bigger) window its resolution hasn't change and therefore appears smaller. the movie command does - to my knowledge - not scale the images and therefore you end up with a smaller movie in a maximized figure.

what you could do is to export your movie to an avi (movie2avi) and play back the movie in your favourite movie player...

Julián Francisco 2011-6-8