FS-lite: get Pyramid zoom levels

[wmoore]

Currently, there's no way to tell what zoom levels are supported by Big FS-lite images. We only know the number of levels (previous assumption was that each level was 50% smaller than the previous level).

Second issue is the ordering of levels. E.g. Example SVS image, the zoom levels are

• 1.0 (71068 x 30342)
• 0.25 (17767 x 7585)
• 0.0624 (4441 x 1896)
• 0.0312 (2220 x 948)

I guess it's more useful to have the SIZES of the zoom levels than the Zoom fraction.

So, the PyramidService? needs a method like

ps.getResolutionSizes()  =>  [ [71068, 30342], [4441, 1896]...]

NB: The list needs to be sorted by size (largest first) so that this gives me a continuous zoom:

re.setResolutionLevel(0)
re.setResolutionLevel(1)
re.setResolutionLevel(2)
... etc. 

[wmoore]

This is required for #9701

[wmoore]

The big image viewer in web has been updated to handle the zoom level info, using hard-coded data while waiting for this data.
​https://github.com/openmicroscopy/openmicroscopy/pull/634

It turns out that what we needed was a simple map of scale to zoom level:
​https://github.com/will-moore/openmicroscopy/commit/4c07e3f1bea4001d4a581badc1c86378265fe19b

This could be easily generated from the list of [sizeX, sizeY] proposed above.

[jmoore]

It should likely be quite straight-forward to get at least a first version of this in, even today. Any objections to the API as it stands in the description?

[jmoore]

API change is in with my cherry-picked commit on ​https://github.com/openmicroscopy/openmicroscopy/pull/634

In general, all of these methods should be simplified (i.e. just on getResolutionDescriptions rather than getTileSizes, etc.), but closing since this will work for the moment. If particular other geometry elements are desired for FS, please mention it.

[Will Moore <will@…>]

(In [36d58d262c8fdd18380af94d56a09540b2141cc8/ome.git] on branch develop) Add PyramidService?.getResolutionDescriptions method (See #9813)

Provide a list of ResolutionDescription? objects which should
eventually represent the entire geometry of the tiled plane.