Why does text move when exporting figure using normalized units?

When I export a figure to a graphics file (e.g., .png or .jpeg), text placed in an axis gets moved from how it appears in the Matlab figure and how it is defined to appear in the code when using normalized units.

Without normalized units, it exports the graphic as expected:

fh = figure;
ph = plot(1,1);
th = text(0.5, 0.5, 'Test');%,'units','normalized');
print test.png -dpng
exportgraphics(fh,'test1.jpg')

However, when exporting the figure with text units normalized, I would expect the text to move to the center of the axis (position 0.5, 0.5), and so it appears on the figure in Matlab, but the saved graphic moves the text to the top right corner of the axis.

fh = figure;
ph = plot(1,1);
th = text(0.5, 0.5, 'Test','units','normalized');
print test.png -dpng
exportgraphics(fh,'test1.jpg')

When saving the graphic from the figure File menu in the GUI, this does not happen; the text appears where it should.

Version: R2022b

Platform: macOS Monterey 12.6.3

Answer 1

[Dinesh]

Hi Dirk.

Different exporting functions (For example "print", "exportgraphics", "saveas") in MATLAB might handle graphics objects differently when exporting figures. This could lead to differences in the appearance of the exported figure compared to the one displayed on the screen.

I don't have access to the specific platform to reproduce the issue. However, I suggest you try the following workaround:

The "saveas" function provides an alternative way to save your figure as an image file. You can try using this function to see if the text positioning is preserved correctly when using normalized units.

fh = figure;
ph = plot(1, 1);
th = text(0.5, 0.5, 'Test', 'units', 'normalized');
saveas(fh, 'test.png');

You can also try adjusting the text position after setting the normalized units by calling the "set" function on the "th" handle.

fh = figure;
ph = plot(1, 1);
th = text(0.5, 0.5, 'Test');
set(th, 'units', 'normalized', 'position', [0.5, 0.5]);
print('test.png', '-dpng');
exportgraphics(fh, 'test1.jpg');

[Dirk]

I'm afraid neither approach worked.

fh = figure;
ph = plot(1,1);
th = text(0.5, 0.5, 'Test');%,'units','normalized');
set(th,'units','normalized','position',[0.5 0.5]);
print test1.png -dpng
exportgraphics(fh,'test2.png')
saveas(fh,'test3.png')

[Dirk]

Saving out the same figure from the GUI still produces expected results:

Answer 2

[Jesse Chao]

Hello @Dirk,

I am experiencing the same issue. I am wondering if you were able to resolve it eventually?

Thank you very much.

Jesse

[Dirk]

Hi @Jesse Chao,

No, unfortunately the problem persists. I have upgraded to macOS Ventura 13.4 (still Matlab R2022b).

Dirk

[Jesse Chao]

Hello @Dirk,

After I tried approaching this problem in multiple settings and ways, I was able to resolve it by using the exportgraphics function with the following settings:

exportgraphics(obj,'filename','ContentType','vector')

% I was planning to generate all my figures into a joined PDF file. Instead, I used this code:
% exportgraphics(obj,'filename.pdf','Append',true,'ContentType','vector')

I specified the figure type as vector instead of an image, and it didn't shift my text location.

Please give it a try and let me know if you were also able to resolve it.

Jesse

[Dirk]

Hi @Jesse Chao,

Thanks for the feedback and testing. Unfortunately, that approach does not work in my configuration.

exportgraphics(fh,'test4.png','ContentType','vector')

Warning: 'ContentType' parameter is ignored when it is set to 'vector' for image output.

However, when I output to a PDF file as you did (with or without appending), the placement of the text is correct. Not a resolution for me, unfortunately, but glad it is working for your purposes.

Dirk

[Jesse Chao]

Hello @Dirk,

I can truly understand your frustration.

I hope the @MathWorks Support Team can fix this issue and provide clearer instructions regarding the problem. In the meantime, I wish you the best of luck in finding a solution or a workaround.

Take care and good luck!

Jesse