Subscripted text and centering of TextSpanner line

[Nick Payne]

 If I have text characters at the left end of a TextSpanner, and some 
of those characters are subscripted, then the centering of the 
TextSpanner line seems to be calculated using the total height of both 
the main and subscripted text, which puts the line at the bottom of the 
main text rather than being centered on it. While this makes some sort 
of sense, I think that asking for the line to be centered means that I'm 
asking for it to be centered on the main text.

%===========================================
\version "2.13.35"

#(set-global-staff-size 30)

\relative c'' {
    \once \override TextSpanner #'bound-details #'left #'text = \markup 
{ \concat { CII " " } }
    \once \override TextSpanner #'style = #'line
    \once \override TextSpanner #'font-shape = #'upright
    \once \override TextSpanner #'direction = #UP
    \once \override TextSpanner #'bound-details #'right #'text =
        \markup { \draw-line #'(0 . -0.5) }
    \once \override TextSpanner #'bound-details #'left 
#'stencil-align-dir-y = #CENTER
    gis16\startTextSpan b e b' e e, b' e\stopTextSpan
    \once \override TextSpanner #'bound-details #'left #'text =
        \markup { \concat { "CII" \sub 3 " " } }
    \once \override TextSpanner #'style = #'line
    \once \override TextSpanner #'font-shape = #'upright
    \once \override TextSpanner #'direction = #UP
    \once \override TextSpanner #'bound-details #'right #'text =
        \markup { \draw-line #'(0 . -0.5) }
    \once \override TextSpanner #'bound-details #'left 
#'stencil-align-dir-y = #CENTER
    gis,,\startTextSpan b e b' e e, b' e\stopTextSpan
}
%===========================================

Nick

test.preview.png
Description: PNG image