Re: How to avoid a collision?

Olivier,

On Thu, May 21, 2015 at 7:26 AM, Olivier Vogel [via Lilypond] <[hidden email]> wrote:

2015-05-21 13:54 GMT+01:00 Kieren MacMillan <[hidden email]>:

May I ask why you’re not using Lilypond’s built-in (and generallly excellent) voice-handling? e.g. In the modified snippet (below), I’m using \voiceOne, \voiceTwo, etc., which eliminates the need for \stemUp, \tieDown, etc., and appears (to my eye) to eliminate all note collisions.

Simply because, I'm learning Lilypond since only a few days.

Well, keep going! You'll get the hang of things. I'd follow Kieren's advice in separating the musical *content* from the score *structure*. You'll find it will pay off. However, there's an unnecessary duplication of identifying voices in his solution. Let me explain. There are basically two ways to create simultaneous voices, an implicit way and an explicit way.

Implicit Voicing:

... old voice before ...

{ ... first voice stuff ... }

{ ... second voice stuff ... }

{ ... third voice stuff ... }

... etc.

... new voice after ...

In this form, there is no need to include \voiceOne, \voiceTwo, etc. unless you *really* mean to change the voice, but normally this is not necessary. Adding them (which is what Kieren did) won't hurt it, it's just unnecessary. This syntax can be convenient if the sections are not too long. However, be aware that this syntax creates COMPLETELY NEW voices and discards the old ones, so don't use this form when you need to attach lyric text. The voice it's connected to will be lost once this section starts.

Explicit Voicing:

... original voice stuff, neutral direction ...

{ \voiceOne ... continuation of original voice (but now as "first") ... }

\new Voice { \voiceTwo ... second voice stuff ... }

\new Voice { \voiceThree ... third voice stuff ... }

\oneVoice

... original voice continues, but without a specified direction ...

Notice that there are no "\\" in between the voices here. I tend to prefer this syntax unless each section is *very* temporary and there are no lyrics involved. Otherwise, this is the way to go.

In either case, the odd numbered voices move associated elements upwards (i.e., stems, slurs, ties, articulations, etc.) and move progressively to the right, away from the primary note column. Even numbered voices move associated elements downwards and move progressively to the left of the primary note column.

Your solution avoids the collision at the third measure, but introduces an horizontal shift at the fourth measure, which I'd like to prevent. Is it possible?

It's certainly possible, but the real issue that keeps makes it this way that LilyPond deals with things tied to specific voices. As of now, there isn't a convenient mechanism that allows you to put a tie across voices. To *fake it*, there are a couple of options:

Use an override similar to what you were using initially (e.g., \override NoteColumn.force-hshift = #0) for both notes in the connected ties of the third voice.
Use a hidden notehead that connects to the first g1 and create a real chord in the first voice for the second set of ties.

In your case, after cooking up both options, the first tends to be easier (when using the voicing that Kieren described) and the second requires the same force-shift override anyway to put the tie in the right place.

p.s. Also note that I abstracted your note code from your score code — it is so much easier to read and debug this way, in my opinion, and it keeps the score block as clean and simple as possible.

Thank you very much for your advice. As a beginner, where can I learn how to write a better code?

Do you mean syntax structure (e.g., where to put the music vs. structure) or coding style (e.g., how much to indent, when to start a new line, etc.)?

Regards,

Abraham

From:	tisimst
Subject:	Re: How to avoid a collision?
Date:	Thu, 21 May 2015 08:11:24 -0700 (MST)