\version "2.15.30"

\markup "accidentals and scripts are precisely skylined:"
{ <cisis''' es''' bes''>2 a''\shortfermata a''\trill a''\lineprall }

\markup "but dynamicTexts still have rectangular skylines."
\markup "This results in dynamicTexts being too far from notes:"
{ c''4\f  a'4^\f }

\markup "Here's how DynamicTexts in the above example should be positioned:"
{
  \once \override DynamicText #'extra-offset = #'(0.0 . 0.5) c''4\f  
  \once \override DynamicText #'extra-offset = #'(0.0 . -0.75) a'4^\f
}