set downsampling factors in the cli

[d-v-b]

I noticed that the default behavior of the cli appears to be anisotropic downsampling, e.g. x and y dimensions get downsampled but not z. Is there a way to change this via the cli? I have isotropic data, and so I want to downsample it isotropically.

[thewtex]

The default behavior is to pick downsampling facts that will result in pixel sizes that will be more uniform in all directions.

Yes, we could add a CLI parameter to specify scale factors by parsing an argument and passing through following:

ngff-zarr/ngff_zarr/to_multiscales.py

Lines 219 to 223 in 4a15499

	scale_factors : int of minimum length, int per scale or dict of spatial dimension int's per scale
	If a single integer, scale factors in spatial dimensions will be increased by a factor of two until this minimum length is reached.
	If a list, integer scale factors to apply uniformly across all spatial dimensions or
	along individual spatial dimensions.
	Examples: 64 or [2, 4] or [{'x': 2, 'y': 4 }, {'x': 5, 'y': 10}]

This would make it easy to specify a desired isotropic spacing.