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Displaying frames captured by getframe(h) at original size

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Donald Liu
Donald Liu on 7 Oct 2021
Commented: Donald Liu on 7 Oct 2021
I captured multiple frames from a figure, and would like to play them back one frame at a time. Please see the below example code:
h = figure;
for i=1:10
plot(rand(20, 1));
grid
title('Original figure');
xlabel('This is the original x label.');
MV(i) = getframe(h);
pause(0.01);
end
% The image displayed in this portion is *smaller* than the original plot,
% as it tries to fit the entire figure within the original axes
for i=1:10
image(MV(i).cdata);
% movie(h, MV(i));
pause;
end
The problem is, when displayed using "image(MV(i).cdata)", the entire content of the figure has to fit within the plotting axes, including title and labels, so there's a shrinkage. I could use "movie(h, MV(i))", which does not cause this rescaling, but "movie" has the bad habbit of clearing the figure each time, so the display is flashing annoyingly. Do you have better solutions? Thanks in advance!

Accepted Answer

Chunru
Chunru on 7 Oct 2021
You can use "imshow" which by default show images in 100% magnification. "doc imshow" for more details.
  3 Comments
Donald Liu
Donald Liu on 7 Oct 2021
truesize did not seem to do what I intended, imshow is still displayed with ax2, and the whole figure is resized automatically:
h = figure;
ax1 = axes('Position', [0.49479 0.20139 0.41276 0.55556]);
ax2 = axes('Position', [0.13 0.52778 0.30359 0.39722]);
for i=1:10
axes(ax1);
plot(rand(20, 1));
grid
title(sprintf('Original figure %d', i));
xlabel('This is the original x label.');
axes(ax2);
plot(rand(100, 1));
MV(i) = getframe(h);
pause(0.01);
end
% Set up a new axes for use by imshow, rather than using the current axes
% axes('Position', [0 0 1 1]);
for i=1:10
imshow(MV(i).cdata, 'Border', 'tight');
truesize();
% image(MV(i).cdata);
pause(0.1);
end
For now I'll go with setting up a new axes('Position', [0 0 1 1]), as in my previous reply. Thanks!

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