[eriksjolund]

How to display circles on top of zoomable images without getting flickering is an interesting problem. (This comment does not refer specifically to displaying a tree map)

I noticed that painting the circles on top of an overlay with OpenSeadragon caused flickering [1]. However, when painting circles on top of the pyramid image tiles that OpenSeadragon loaded, there was no flickering.

This was my conclusion in 2016 when I created a web viewer that showed circles on top of a microscope photo [2]. Architecture: single file format containing an index, pyramid image tiles and measurement data for circles. To make this work, I intercepted the function call that OpenSeadragon usually uses to download an image tile. Instead, I provided OpenSeadragon with an image tile that already had the circle painted on it.

[1] https://openseadragon.github.io/examples/ui-overlays/ [2] demo: https://eriksjolund.github.io/osd-spot-viewer-webpack-build/... (The demo only worked on Linux. I'm not sure if it still works) source code: https://github.com/eriksjolund/osd-spot-viewer