Export figure is painfully slow. Save as png is fast. Why?

I tend to export some figures for use in presentations etc. I have noticed that for some figures (perhaps those with lots of data), Matlab will grind to a halt when I try to export the image to the OS pasting buffer. Sometimes I end up killing the Matlab session.

Recently, I figured out that if I instead save the image as e.g. *.png, it is really fast. Any idea why this is? Is it a bug? How hard can it be to render into a VGA-ish image buffer?

Answer 1

[Patrick Kalita]

The reason is that MATLAB is not exactly rendering to a "VGA-ish image buffer" when you copy to clipboard. The default setting is for MATLAB to attempt to copy in a Windows Metafile format. This format mixes vector and bitmap elements. So, yeah, if you have a lot of data and it is trying to encode those in a vector format, it could take a while.

You do have control over the format MATLAB uses for figure copying. In a figure window select Edit -> Copy Options. In the Preferences dialog that opens if you select "Bitmap" you will get a simple bitmap version of the figure copied to the clipboard -- which should be faster.