RFE: add more settings to Labels category of Preferences dialog

[Elaine Meng]

Three somewhat interrelated suggestions:

(A) Currently there is a Labels section in the Preferences dialog but it only has label height (settable with label command "defaultHeight" option). Several other label settings could appear here, such as color, background color, and text contents (which attribute values to show for atoms and residues, and in what format). For 3D labels in general, these do not yet have user-settable defaults, only factory defaults.

(B) Specifically for zone labels, there are user-settable defaults (via "zone setting" command). Perhaps these could also appear in the Labels section of the Preferences dialog.

(C) If there need to be commands for the users to set their own 3D label defaults, consider adding a "label setting" subcommand analogous to "zone setting" and moving the current "defaultHeight" option of the top-level command to an option of this subcommand. Maybe also the "orient" option. Many of the current "label" options take the value "default" which means the factory default. That might be OK even with a "label setting" command if the documentation makes clear what they mean.

[Tom Goddard]

It would be nice to see all those options in Preferences / Labels. I think the only two values a user is likely to change is default label height, and default text contents. For color, background color, and orient I think it would be very unusual for anyone to change the default values from auto, none, 0, so those are a lower priority Currently there is not even a command capability to change the default text contents.