MATLAB: Figure size changes randomly

figurelinuxMATLAB

I've recently started using Matlab R2014B for Linux (on Ubuntu 14.04). Previously I used R2014B on Windows 7. Some code does not work after the switch and I've tracked the problem down to an issue with the size of figures changing randomly:

close all; clear all;
hFig = figure('Color','White');
set(hFig, 'Position', [400 100 560 700])
f = getframe(gcf);
% Get figure size
pos = get(gcf, 'Position')

The problem is that the created figure has a size that is not equal to the specified size. For example it could be

pos =
   395    95   570   702

But it changes every time I run the code.

Any ideas on this?

EDIT I noticed that the figure is not exactly at the same position I run the code, which explains the wrong position info but what is the cause behind this and how to remedy it?

Best Answer

Did you try to insert a drawnow before getframe? Sometimes pause(0.02) allows the Java objects to be updated also.

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MATLAB: I seem to be having an error using movie2avi (even using the example shown in Matlab Help) What could be the issue

Matt - the zooming in of the figure that occurs when you execute movie(mov) may be due to the fact that the figure that the movie is being played on has not been resized to the frame size. You could try

 [h,w,p] = size(mov(1).cdata);  % use 1st frame to get dimensions
 hf = figure; 
 % resize figure based on frame's w x h, and place at (150, 150)
 set(hf, 'position', [150 150 w h]);
 axis off
 movie(hf,mov,1,30,[0 0 0 0]);

to see if the above prevents the zooming.

As for only observing the first frame, I tried your code on a 32-bit R2014a version of MATLAB (Windows Vista), and I observed the same results. Even when I used the VideoWriter class to write the frames to file, all frames were identical to the first one (and had what appeared to be other artifacts from my desktop mixed in with the image).

A similar question was raised at stackoverflow: problems with movie file creation, and one solution was to change the figure renderer property to zbuffer (the default renderer is OpenGl for my PC). I added the middle line of code

 set(gcf,'position',[1 35 scrsz(3)/1.2 scrsz(4)/1.2],'color','white') 
 set(gcf,'renderer','zbuffer');         % <---- New line of code
 set(gca,'nextplot','replacechildren');

and created the avi. Both the movie(mov) and the avi worked - all frames were shown (none appeared to be identical). I tried this with your above code, and the VideoWriter alternative.

MATLAB: Moving a Figure’s position inside a script

Are you sure?

Try to add a drawnow command to allow Matlab to update the display.

Best Answer

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MATLAB: I seem to be having an error using movie2avi (even using the example shown in Matlab Help) What could be the issue

MATLAB: Moving a Figure’s position inside a script

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