The new test was failing on the MINGW CI because that is running with `--no-gui-libs`. Attempting to print an invisible figure seems to fail with the fltk graphics toolkit:

>>>>> processing D:\a\octave\octave\scripts\plot\util\print.m
***** test
 hf = figure ("visible", "off");
 unwind_protect
   x = 0:0.1:1;
   hax = axes (hf);
   plot (hax, x, x);
   tmp_name = tempname ();
   print (hf, tmp_name, "-dpng");
   assert (isfile ([tmp_name ".png"]));
   unlink ([tmp_name ".png"]);
   print (hf, tmp_name, "-dpng", "-no-append-file-extension");
   assert (isfile (tmp_name));
   unlink (tmp_name);
 unwind_protect_cleanup
   close (hf);
 end_unwind_protect
!!!!! test failed
print: rendering with fltk toolkit requires visible figure (DISPLAY='')

Should be fixed here:
https://hg.savannah.gnu.org/hgweb/octave/rev/774c54278e97

I pushed the patch to the default branch here:
https://hg.savannah.gnu.org/hgweb/octave/rev/d668c52cf2e6

It should be part of Octave 9 when it will be released (probably some time early next year).

Marking as ready for test.

Oops. Forgot about that preference.

See the updated patch.

(file #55089)

Does the attached patch work for you?

I chose the flag "-no_append_file_extension" for this new feature. The long name and the underscores in the flag make it hopefully very unlikely that this will ever collide with a new flag in a future Matlab version.

I haven't tested extensively yet whether this works for all possible formats with all possible toolchains and combinations of flags. Only checked "-dpng" and "-dsvg" with default flags so far.


(file #55088)

I'm guessing you are referring to the `saveas` function. Is that correct?

If you do, I don't know how that could be done without breaking compatibility with Matlab:
https://de.mathworks.com/help/matlab/ref/saveas.html

> saveas(fig,filename,formattype) creates the file using the specified file format, formattype. If you do not specify a file extension in the file name, for example, 'myplot', then the standard extension corresponding to the specified format automatically appends to the file name. If you specify a file extension, it does not have to match the format. saveas uses formattype for the format, but saves the file with the specified extension. Thus, the file extension might not match the actual format used.

Is there another function that you have in mind?

The same goes for the `print` function:
https://de.mathworks.com/help/matlab/ref/print.html

> print(filename,formattype) saves the current figure to a file using the specified file format, such as print('BarPlot','-dpng'). If the file name does not include an extension, then print appends the appropriate one.