Re: Because item pure heights are cached, the logic in Accidental_interface::pure_height doesn't work. … (issu e 42490046)

[k-ohara5a5a]

The drawback is that the glyph for each accidental, rather than being
looked up 5 times (already bad) would be looked up 14 times with this
patch.

The fundamental problem seems to be that that the 'stencil property is
set to ly:accidental-interface::print(), and that print function checks
whether the accidental is in a tie (unbroken across lines) an deletes
the Accidental if so.   Thus we cannot store the stencil in 'stencil
until we are absolutely sure we want it.

Could you move the check for ties from accidental::print(), and the
similar check in accidental::pure-height(), to a new function linked to
Accidental.after-line-breaking ?

Then accidentals can build their true stencil just once (whether they
need it or not, but better than building it 14 times throwing away 13)
without any 'pure' complication, and the check for ties (not broken
across lines) is linked to a more expected property,
'after-line-breaking.

https://codereview.appspot.com/42490046/