Can we remove a warning in visualizer?

[mzr1996]

The below warning is verbose, I just want to use the visualizer to draw some images, but don't want to save it anywhere. So I don't want to pass a save_dir argument.

mmengine/mmengine/visualization/visualizer.py

Lines 165 to 167 in c712070

	if save_dir is None:
	warnings.warn('`Visualizer` backend is not initialized '
	'because save_dir is None.')

[mzr1996]

@Harold-lkk

[Harold-lkk]

Maybe setting the default of save_dir to "save_dir" instead of None?

[mzr1996]

Maybe setting the default of save_dir to "save_dir" instead of None?

Since the save_dir is only used to make the path of every backend, I think you can raise this warning only if the vis_backends is not None.

[Luo-Yihang]

@mzr1996 I agree with you that this warning is unnecessary. It would be better to include this if branch only if the vis_backends is not None. I plan to raise a pull request to implement this change. Please let me know your thoughts on this.