Line numbers for soft-wrapped styled text?

[Richard Gaskin]

When I first started down this road I went for getting max values from 
the styledText array, similar (though far less efficiently) to how Alex 
Tweedly solved this so well in his post the other day:
http://lists.runrev.com/pipermail/use-livecode/2017-March/235688.html

Great work as usual from Alex there, reasonably performant enough for 
most needs and very well crafted.

This morning Jim Lambert emailed me a very different solution that I 
thought would be worth sharing here.

Here he uses the engine's own metrics for calculating vertical line 
spacings, by having the number field placed below the editable text 
field, setting its width to that of the editable field + a left margin 
in which he uses the engine's support for numeric list styles to draw 
the line numbers:

on textchanged
    lock screen
    set the htmltext of fld "nums" to the htmltext of me
    set the liststyle of line 1 to -1 of fld nums to "decimal"
    set the scroll of fld "nums" to the scroll of me
end textchanged

The only downside I can see to this approach is for memory, as it 
requires copying the full styled text from the source field into the 
line number field.

Very minor drawbacks for my needs are aesthetic:  I prefer a line number 
field without trailing decimal points ("1" rather than "1." as LC's 
listStyle renders), and that line number be left-aligned by LC renders 
its list line numbers left-aligned.

But overall quite nice, and very snappy. Thanks, Jim!

-- 
  Richard Gaskin
  Fourth World Systems
  Software Design and Development for the Desktop, Mobile, and the Web
  ____________________________________________________________________
  Ambassador at FourthWorld.com                http://www.FourthWorld.com