The overview uses the smallest available image size and not the best one

[andreasg123]

Describe the bug

bioformats2raw produces very small images at the lowest level of the image pyramid. In one sample image (about 70,000 pixels in the larger dimension), the smallest image was 63x136. The overview happened to be twice that large in each dimension. However, it loaded the smallest available image, making the overview look pixelated. Making bioformats2raw produce fewer levels would require determining the image dimensions upfront to specify the number of resolutions, an undesirable option given the many different possible input formats.

Expected behavior

OverviewView._setHeightWidthScale pretty much computes the best zoom level. However, OverviewView.filterViewState uses instead -(this.loader.length - 1) as the zoom level.

Environment:

• Release or git hash: 0.10.3
• Browser: Chrome

[manzt]

What about exposing this behavior as a parameter, with the suggested change as default behavior? My guess is that most images will be generated with bioformats2raw, but some may not.

[ilan-gold]

@andreasg123 If you want to see this done, would you be willing to open a PR? It sounds like you understand the problem well (thank you very much for poring over my code). I think you would need to update the underlying layer as well to fetch the right zoom level.

[ilan-gold]

I could do it, but not for at least another week.

[ilan-gold]

As for @manzt's comment, I don't feel strongly. Exposing things can create more work in the future due to maintenance or prevent work from needing to be done for exposing the API.

[andreasg123]

@ilan-gold, I'll see if I can find time to do this. I don't think that this needs to be a parameter because the behavior that I proposed matches what the detail view does.