Transparency slider and interactive mode does not work for centroid-and-size-only annotations

[kheffah]

In the screenshot below, the annotation transparency slider is set to zero, yet the centroid-and-size-only (CASO) elements are not affected and retain their "native" fill value.

A related problem occurs when I activate interactive mode and hover over an the element text -- it fades everything except the element itself (expected behavior) but fails to fade out CASO elements (the bug).

If the simplest fix for this is to not show transparency for CASO elements, that's totally OK. The issue of interactive mode for CASO elements remains withstanding even if this simple fix is adopted, though.

[kheffah]

@manthey While I doubt this issue and issue DigitalSlideArchive/HistomicsTK#719 are related, I'm just turning your attention to this in case they are .

[kheffah]

@manthey If the simplest fix for this is to not show transparency for CASO elements, that's totally OK. The issue of interactive mode for CASO elements remains withstanding even if this simple fix is adopted, though.

[manthey]

This is a more complex issue that it initially appeared. We have some code that implies we intended to not highlight an element when there were too many of them to remain performant (default is 5000), but, when we load centroids the number of elements that AREN'T centroids is often below this threshold which leads to inconsistent behavior. One solution would be to prevent highlighting annotations if part of the elements are shown as centroids. The other option would be to see if we can improve the performance of toggling large numbers of opacities and then do it for centroid annotations, too.