Scrollbars on *View or better VirtualFlow based UI elements

Werner Lehmann lehmann at
Mon Dec 15 15:35:27 UTC 2014

Hi Tomas,

On 15.12.2014 16:10, Tomas Mikula wrote:
> To add an idea, semi-transparent scrollbars could be shown over the
> content when the mouse approaches the edge. This would avoid
> flickering andto save space at the same time. I realize one could not
> use this if the scrollbars would cover some interactive controls at
> the edge of the content.

Sounds similar to invisible scrollbars which appear on hover only. 
Personally I don't like either one. I guess it is a matter of taste. In 
a touch scenario it is a bit of problem though because usually you 
cannot rely on hover events.

> Also, I would like to see some new creative way of scrolling the
> content, especially for cases when the full length of the content is
> not known, e.g. a ListView with variable cell sizes, or a possibly
> infinite stream of items that are loaded as needed. In these cases,
> the scrollbar length always lies about the actual total length of the
> content.

If you have variable cell sizes an easy way to map this to a scrollbar 
is to use the number of items, possibly with some adjustments involving 
the height of the known cells. From my impression this is what virtual 
flow does but I could be wrong.

An infinite stream of items can be scrolled with the "Google Picasa" 
light table approach. You can find an implementation of this concept in 
ControlsFX, see the PlusMinusSlider control.


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