Independent left- and right-control of bound-padding?

[Trevor Bača]

Hi,

Still working on edge-text adjustments ...

In the snippet below, I've got exactly what I want -- thanks to much
help from the list -- with the one exception that the padding of the
two vertical spanners is off-center relative to each piece of edge
text. Notice that the solid horizontal line runs into the (lefthand
sides) of the "b" and "c" edge text (though the righthand sides are
nicely cushioned by whitespace).

%%% BEGIN BOUND PADDING SNIPPET 1 %%%

\version "2.9.17"

\new Staff \with {
  \override TextSpanner #'dash-fraction = #'()
  \override TextSpanner #'direction = #down
  \override TextSpanner #'bound-padding = #1
} <<
  \time 3/8
  \new Voice {
     c'8 c'8 c'8
  }
  \new Voice \with {
     \override TextSpanner #'staff-padding = #3
  } {
     \override TextSpanner #'edge-text = #(cons
        (markup #:hcenter #:combine #:transparent "f" "a")
        (markup #:hcenter #:combine #:transparent "f" " "))
     s8 \startTextSpan
     \override TextSpanner #'edge-text = #(cons
        (markup #:hcenter #:combine #:transparent "f" "b")
        (markup #:hcenter #:combine #:transparent "f" "c"))
     s8 \stopTextSpan \startTextSpan
     s8 \stopTextSpan
  }
> >

%%% END BOUND PADDING SNIPPET 1 %%%

So the question is: "Is there a way to control left- and
right-bound-padding independently?". I'd like to say something like
...

 \override TextSpanner #'bound-padding-left = #1
 \override TextSpanner #'bound-padding-right = #2

... to open extra space on only the right end of each vertical spanner
(relative to each piece of edge text).

Alternatively, can any of the markup genies conjure up some other
solution that will get me what I want?

(Thanks again for the all the help so far; it's amazing how far markup
is able to go ...)


--
Trevor Bača
address@hidden
... like the dew, or like lightning ...