Scroll user experience

[rpbouman]

Scrolling feels slower than necessary. For a large part this is due to how we handle it now:

• we buffer scroll events and wait for a timeout (couple of hundred milliseconds)
• when the timeout expires, we switch to a busy state, which pops up a progress indicator and blurs the output
• we do a query when necessary, and then render the results.

The consequence of this approach is that every scroll movement feels as if it requires backend action. Even when we have a suitable amount of cached tuples and cells, it still feel slow.

what we should do is:

• immediately respond to scroll event, or at the very least shorten the timeout
• whatever amount of data we can serve from the cache should immediately be rendered without popping up the spinner
• after all scroll events died out, check if are missing tuples/cells, and if necessary, pop up a spinner and do the necessary backend queries.

[declann]

+1

"infinite scroll" table in Mosaic has very nice feel: https://idl.uw.edu/mosaic/examples/table.html