11. Measures

11.1. Understanding measures in LilyPond

In LilyPond you specify time signatures by hand and LilyPond creates measures automatically:

\new Staff {
    \time 3/8
    c'8
    d'8
    e'8
    d'8
    e'8
    f'8
    \time 2/4
    g'4
    e'4
    f'4
    d'4
    c'2
}

Here LilyPond creates five measures from two time signatures. This happens because behind-the-scenes LilyPond time-keeping tells the program when measures start and stop and how to draw the barlines that come between them.

11.2. Understanding measures in Abjad

Measures are optional in Abjad, too, and you may omit them in favor of time signatures:

abjad> staff = Staff("c'8 d'8 e'8 d'8 e'8 f'8 g'4 e'4 f'4 d'4 c'2")

abjad> contexttools.TimeSignatureMark((3, 8))(staff)
abjad> contexttools.TimeSignatureMark((2, 4))(staff[6])

abjad> show(staff)

But you may also include explicit measures in the Abjad scores you build. The following sections explain how.

11.3. Creating measures

Create a measure with a meter and music:

abjad> measure = Measure((3, 8), "c'8 d'8 e'8")

abjad> f(measure)
{
        \time 3/8
        c'8
        d'8
        e'8
}

abjad> show(measure)

11.4. Working with dynamic measures

Dynamic measures adjust their time signatures on the fly as you add and remove music.

Create dynamic measures without a time signature:

abjad> measure = measuretools.DynamicMeasure("c'8 d'8 e'8")

abjad> show(measure)

11.5. Adding music to dynamic measures

Add music to dynamic measures the same as to all containers:

abjad> measure.extend([Note("fs'8"), Note("gs'8")])

abjad> show(measure)

11.6. Removing music from dynamic measures

Remove music from dynamic measures the same as with other containers:

abjad> del(measure[1:3])

abjad> show(measure)

11.7. Setting the denominator of dynamic measures

You can set the denominator of dynamic measures to any integer power of 2:

abjad> measure.denominator = 32

abjad> show(measure)

11.8. Suppressing the meter of dynamic measures

You can temporarily suppress the meter of dynamic measures:

abjad> measure.suppress_meter = True

abjad> f(measure)
{
        c'8
        fs'8
        gs'8
}

LilyPond will engrave the last active meter.

11.9. Working with anonymous measures

Anonymous determine their time signatures on the fly and then hide them at format time.

Create anonymous measures without a time signature:

abjad> measure = measuretools.AnonymousMeasure("c'8 d'8 e'8")

abjad> show(measure)

11.10. Adding music to anonymous measures

Add music to anonymous measures the same as to other containers:

abjad> measure.extend([Note("fs'8"), Note("gs'8")])

abjad> show(measure)

11.11. Removing music from anonymous measures

Remove music from anonymous measure the same as from other containers:

abjad> del(measure[1:3])

abjad> show(measure)