Refresh annotate on figure in loop

2020 10 7
1 个回答
更新时间：2020 10 9
6 次查看（30 天）

0 个投票

Hello.
I have read several other solutions that use various methods to replace an annotation with each figure refresh, but none of them seem to work for me. The annotations just keep stacking to the side of the first.
I've tried the solutions found here (to no avail):
https://www.mathworks.com/matlabcentral/answers/334288-how-do-i-delete-all-annotations-on-a-figure-but-not-do-clf
https://www.mathworks.com/matlabcentral/answers/423459-how-to-refresh-annotation-after-each-frame
https://www.mathworks.com/matlabcentral/answers/398319-anottations-are-overlapping-in-each-loop-interaction
figure;
a1 = [];
a2 = [];
for k = 1:K
%compute indices for the current frame
n = (1:N)+(N*(k-1));
%signal 1
x = s1(n);
E_m1(k) = (x'*x)/N; %Normalized frame energy
subplot(211);
plot(n,s1(n),'b',n,e(n),'g:');
%annotation stuff
str1 = sprintf('NFE %d', E_m1);
dim1 = [0.662 0.622 .3 .3];
delete(a1);
a1 = annotation('textbox',dim1,'string',str1,'FitBoxToText','on');
%pause between frames, waiting for keypress
pause(1)
end
Thanks for your time.

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回答（1 个）

Rik
Rik 2020-10-8

0 个投票

Create the annotation object once, and update the String property inside your loop.
I would suggest drawnow to trigger the update of the graphics and to process any queued callbacks (e.g. those triggered by keypresses).

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Tharon
Tharon 2020-10-8
编辑：Tharon 2020-10-8
I don't think this is what I'm trying to do. I need two annotations (a1, a2) because I am concurrently annotating two subplots with different annotations. The second subplot is in the same loop. Both annotations receive the updated values to the right of the original annotation instead of in replacement of. The code above is just an example of what one of the subplots annotation attempt looks like.
The solution found here: https://www.mathworks.com/matlabcentral/answers/398319-anottations-are-overlapping-in-each-loop-interaction
Is exactly what I want to do, but it does not work for me. Could it be because my x-axis values change with each loop iteration?
Rik
Rik 2020-10-8
I don't see the problem of having two annotations, you just have to keep track of two handles:
figure;
a1 = [];
a2 = [];
for k = 1:K
%compute indices for the current frame
n = (1:N)+(N*(k-1));
%signal 1
x = s1(n);
E_m1(k) = (x'*x)/N; %Normalized frame energy
%signal 2
x = s2(n);
E_m2(k) = (x'*x)/N; %Normalized frame energy
ax1=subplot(2,1,1);
plot(n,s1(n),'b',n,e(n),'g:','Parent',ax1);
% ^^^^^^^^^^^^
% use explicit handles here as well
%annotation stuff
str1 = sprintf('NFE %d', E_m1);
str2 = sprintf('NFE %d', E_m2);
dim1 = [0.662 0.622 .3 .3];
dim2 = ___;
if k==1
a1 = annotation('textbox',dim1,'string',str1,'FitBoxToText','on');
a2 = annotation('textbox',dim2,'string',str2,'FitBoxToText','on');
else
set(a1,'Position',dim1,'String',str1);
set(a2,'Position',dim2,'String',str2);
drawnow;%trigger graphics update
end
%pause between frames, waiting for keypress
pause(1)
end
Tharon
Tharon 2020-10-8
Thank you, I will try this soon.
Tharon
Tharon 2020-10-9
Thanks for all of your help so far Rik, but I am still having trouble. I implemented the changes you suggested. Now it seems that instead of stacking the new annotations to the right, it stacks them under the previous:

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Tharon
Tharon
2020-10-7

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2020-10-9

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