Re: Dot-notehead collision

[Carl Sorensen]

On 3/15/11 2:59 PM, "address@hidden" <address@hidden> wrote:

> On Mar 15, 2011, at 5:04 PM, Phil Holmes wrote:
> 
>> ----- Original Message ----- From: "Trevor Daniels" <address@hidden>
>> To: <address@hidden>; "lilypond-user" <address@hidden>
>> Sent: Tuesday, March 15, 2011 6:24 PM
>> Subject: Re: Dot-notehead collision
>> 
>> 
>>> 
>>> address@hidden wrote Tuesday, March 15, 2011 5:00 PM
>>> 
>>>> \relative c' { \time 3/4 << { <cis a'>4 <b fis'>2 } \\ { d2. } >> }
>>>> 
>>>> Produces the attached output.  Is there a way to get it so that the dot
>>>> does not collide with the notehead (w/o resorting to extra offsets and the
>>>> like)?
>>> 
>>> I don't think so.  You'll need 'force-hshift.
>>> 
>>> Trevor
>> 
>> 
>> Agreed. I tried a number of other things, but h-shift worked out of the box.
>> 
>> 
> 
> Perhaps a stupid question - in traditional engraving, is there ever an
> instance where, in 2 voice polyphony, the note column w/ a downward pointing
> stem is placed to the right of note column with an upward pointing stem?  I
> hacked a solution that does this and it looks much clearer than moving in the
> other direction (see attached).  However, if it is not Kosher, I'll scrub it.
> 
> \relative c' { \time 3/4 << { <cis a'>4 <b fis'>2 }
> \\ { \once \override Voice . NoteColumn #'force-hshift = #1.25 d2. } >> }
> 
> \relative c' { \time 3/4 << { <cis a'>4 <b fis'>2 }
> \\ { \once \override Voice . NoteColumn #'force-hshift = #-1.25 d2. } >> }
> 
> 

In the words of Read (p. 68) "When two separate note-heads are required for
a unison, it is important to differentiate the voices clearly.  The note
having its stem *up* (almost invariably the upper voice) is positioned
first, to the left, while the note with the *downward* stem (lower voice,
ususally, goes to the right -- as shown in the previous two lower examples.
The validity of this principle is especially apparent when when the
down-stemmed note is dotted (left-hand example belos).  Whe, however, the
upward-stemmed note is dotted, it is positioned to the right so that the dot
will not be obscured (right, below)."

So, in my reading of his words, the downward stem is normally to the right
of the upward stem.  But if there's a dot, the upward stem will be to the
right of the downward stem to avoid collisions.

So in your example, the first snippet is right, the second snippet is wrong.
This almost exactly matches Read's examples.

HTH,

Carl