Issue 1053 in lilypond: Severe overestimation of line height for significantly non-rectangular systems

[lilypond]

Status: New
Owner: ----

New issue 1053 by shingarov: Severe overestimation of line height for  
significantly non-rectangular systems
http://code.google.com/p/lilypond/issues/detail?id=1053

The page breaking algorithm in Lilypond estimates the spacing between lines
based on the simplified view of their shape as rectangular.  The problem,
and the current hack around it, is explained in the comment inside
Align_interface::get_skylines():

"It's quite common for a treble clef to be the highest element of one
system and for a low note (or lyrics) to be the lowest note on another. The
two will never collide, but the pure-height stuff only works with bounding
boxes, so it doesn't know that. The result is a significant over-estimation
of the pure-height, especially on systems with many staves. To correct for
this, we build a skyline in two parts: the part we did above contains most
of the grobs (note-heads, etc.) while the bit we're about to do only
contains the breakable grobs at the beginning of the system. This way, the
tall treble clefs are only compared with the treble clefs of the other
staff and they will be ignored if the staff above is, for example, lyrics."

Unfortunately, this solution only works for space between staffs inside a
system.  For systems consisting of several staffs, this is not a
significant problem: the inter-system space is only a small percentage of
the whole height, causing only a very small overestimation for page
breaking purposes; however, when systems consist of only one staff each,
this problem becomes critical.

For example, music for voice solo, will suffer from huge empty space at the
bottom of pages.  See "lyrics.ly" for a simple example.

Also, any one-staff music containing enough notes on low ledger lines, will
also suffer in the same way.  See "no-lyrics.ly" for a simple example.

Attachments:
        lyrics.ly  2.9 KB
        no-lyrics.ly  2.3 KB

--
You received this message because you are listed in the owner
or CC fields of this issue, or because you starred this issue.
You may adjust your issue notification preferences at:
http://code.google.com/hosting/settings