Table: rounded selection

[DevCharly]

This PR enables using "rounded" selection for table selection.

This is not yet used in any theme, but intended to be used in the future.

Examples

Row selection

UI properties for above screenshot (see Application properties files):

Table.selectionArc = 6
Table.selectionInsets = 0,1,0,1

Column selection

UI properties for above screenshot:

Table.selectionArc = 6

Cell selection

UI properties for above screenshot:

Table.selectionArc = 6
Table.selectionInsets = 0,1,0,1

[DevCharly]

A snapshot for this PR is now available.
Use PR-856-SNAPSHOT as version.
https://github.com/JFormDesigner/FlatLaf#snapshots

[DJ-Raven]

I see this Issues when selected row then unselected some row

[stefanoschalkidis]

I can confirm the issue for MULTIPLE_INTERVAL_SELECTION. Also, if one selects a few lines, leaves out a line, selects a line, and then selects the left out line there will be a dent at the edge of the selection. SINGLE_SELECTION works fine.

[DevCharly]

@DJ-Raven and @stefanoschalkidis many thanks for reporting.
Should be fixed now 😉