How can I create animated GIF images in MATLAB ?

I would like to know if there is MATLAB functionality to create an animated GIF in MATLAB.

Answer 1

[MathWorks Support Team]

In MATLAB 2022a, export to GIF format is supported by the exportgraphics function using the ‘Append’ option.  For example:

x = 0:0.01:1;
p = plot(nan,nan);
p.XData = x;
for n = 1:0.5:5
      p.YData = x.^n;
      exportgraphics(gcf,'testAnimated.gif','Append',true);
end

For releases prior to R2022a, follow the example "Write Animated GIF" on the imwrite reference page.

[Royi Avital]

Could you add support for APNG? It is much superior to GIF.

[Chad Greene]

Royi has a good point!

[Michael Abboud]

That's a good suggestion, thanks for commenting! I have submitted an enhancement request for this functionality, so it may be considered for a future release of MATLAB.

[Michael Chan]

Very useful and easy to modify. Thanks a lot.

[Coleman Barrie]

Thank you for writing this very helpful as a framework to modify

[Peter Beringer]

Can the GIF then be converted into a *.AVI or *.MOV file within MATLAB?

[Peter Beringer]

Could you please provide comment for what this line does? Why does it return a picture of a kid when evaluated on its own? I'm not sure how to modify it because there's no explanation of what it's doing. Thanks.

[imind,cm] = rgb2ind(im,256); 

[Peter Beringer]

I'm trying to make this work with a surface plot and not getting very far. Is someone please available to give me some proper help rather than lazily posting a link to another very vaguely related thread?

[Adam Danz]

@Peter Beringer, "Can the GIF then be converted into a *.AVI or *.MOV file within MATLAB?"

You can use gif2avi() from the file exchange to convert from GIF to AVI or MP4 format.

https://www.mathworks.com/matlabcentral/fileexchange/76198-gif2avi

[Steven Lord]

Why does it return a picture of a kid when evaluated on its own?

What did you pass into rgb2ind when you called it? Did you call image with no inputs, capture the result using getframe and frame2im, and then call rgb2ind on the result? If so the picture of a kid is not coming from rgb2ind but from image. Steve Eddins explains what's going on in this post on his blog.

As for what the rgb2ind line is doing: getframe returns a struct array. imwrite doesn't know how to accept that struct array as its first (or first two) inputs. frame2im turns that struct array into an image that imwrite could accept, but the image may have more colors in it than the image file format supports so rgb2ind modifies the image to use a colormap with at most 256 colors. It is that image and colormap pair that imwrite writes to the file.

If the bounding box for your surface plot was the same each time you plotted, I would expect this to work. But if the surface plot was rotated or enlarged (so that the area on the screen taken up by each frame would be different) that would be a problem. It would be like printing a report where the first page was on a sheet of letter paper, the second was a 3x5 index card, and the third was a sheet of legal sized paper. That wouldn't make for a very stable stack of reports.

[Joydeb Saha]

how can I select my png images to run the code?

the files are: abc_20190304_0001.png to abc_20190304_0095.png

[Walter Roberson]

@Joydeb Saha

prefix = 'abc_20190304'
dinfo = dir( [prefix '*.png']);
filenames = {dinfo.name};
for K = 1 : length(filenames)
   work with file name in filenames{K}
end

[huanyu]

When using exportgraphics to save gif, can I set the delaytime? I have not found such options in exportgraphics.

[Adam Danz]

@huanyu

exportgraphics does not currently have an option to control frame rate of GIFs.

The documentation for exportgraphics > Append argument suggests to use imwrite for more elaborate graphics. Also see Write Animated GIF.

[huanyu]

@Adam Danz

Thanks for your comment, I have used imwrite to generate gif successfully.

Answer 2

[Chad Greene]

Or, for a much simpler option, use the gif function on File Exchange.

[Will Reeves]

... if you're operating on figure window rather than image data?

Answer 3

[Shashank Rai]

x = 0:0.01:1;
figure(1)
filename = 'testnew51.gif';
for n = 1:0.5:5
      y = x.^n;
      plot(x,y)
      drawnow
      frame = getframe(1);
      im = frame2im(frame);
      [imind,cm] = rgb2ind(im,256);
      if n == 1;
          imwrite(imind,cm,filename,'gif', 'Loopcount',inf);
      else
          imwrite(imind,cm,filename,'gif','WriteMode','append');
      end
end

[Coleman Barrie]

Thank you for writing this very helpful as a framework to modify

[Fei Jia]

Thank you! This helped me in creating a gif for my student.

Answer 4

[Alec]

So it appears that `imwrite` now supports writing animated grayscale GIFs "When writing multiframe GIF images, X should be an 4-dimensional M-by-N-by-1-by-P array, where P is the number of frames to write."

But if I try to pass it an M-by-N-by-3-by-P it seems to treat each RGB color channel as a separate grayscale frame. Is there now way to write an animated color GIF without a for loop over the frames?

[Will Reeves]

... clearly still not after nearly a decade!? rgb2ind only operates on single images - not very helpful. To work around this I had to "stict" all my frames into a single image to create the colour map, and then use that for the export. Doesn't seem very elegent... is there a better way?

can rgb2ind be overloaded in a future release to work with m x n x 3 x frames 4D matricies?

[DGM]

MIMT gifwrite() works to write I/IA/RGB/RGBA and indexed color images from 4D arrays. MIMT gifread() can read the image with minimal hassle.

https://www.mathworks.com/matlabcentral/fileexchange/52514-tools-to-read-and-write-animated-gif-files

Pay attention to the synopsis if you intend to read GIF files in versions newer than R2018a -- regardless of what tools you're using. If you're using a newer version, you will not be able to correctly read most multiframe color GIF files unless you make that effort.

Stitching the frames together to generate a colormap is a bad idea, since it means that no frame can have a unique optimized local color table. The more dynamic the color content is over the sequence, the worse the entire image will look.