Support PAE mixed time signatures in Verovio

[ahankinson]

Describe the problem Mixed time signatures, e.g., c3/2 are not supported

To Reproduce Steps to reproduce the behavior:

1. Visit the PAE Online Editor
2. Enter c3/2 as the time signature
3. Observe that Verovio only renders the c component.

Expected behavior The full time signature would be rendered

Verovio information

• Latest version on the PAE Online Editor

Additional context Mixed meters are explicitly allowed in the PAE Specification

[lpugin]

Related to https://github.com/rism-digital/verovio/issues/800 See the current MEI guidelines https://music-encoding.org/guidelines/dev/data-types/data.METERFORM.html

[ahankinson]

Just updated the text to specify that it's "mixed" time signatures.

Axel's suggestion in #800 seems reasonable?

<measure>
  <staff n="1">
    <layer n="1">
      <meterSigGrp func="mixed">
        <meterSig sym="cut"/>
        <meterSig count="3" unit="1" form="num"/>
      </meterSigGrp>
    </layer>
  </staff>
</measure>

[lpugin]

I am not sure this is a complex metrical pattern and it looks over the top to me. Everything fits within a <meterSig> and it seems to be simply a display encoding problem. It would be good to hear @pe-ro's opinion about it.

[rettinghaus]

It it connected to https://github.com/music-encoding/music-encoding/pull/848 and the overall discussion in https://github.com/music-encoding/music-encoding/discussions/826.

[ahankinson]

But this seems to be exactly what <meterSigGrp> is meant for: "Used to capture alternating, interchanging, and mixed meter signatures."

@rettinghaus I don't think it's related to the mensural discussions.

[rettinghaus]

Well, it looks mensural to me. I would be interested how the actual music looks like.

[lpugin]

It can be both, CWMN and mensural. You can see some CWMN examples here https://github.com/music-encoding/music-encoding/issues/504#issuecomment-387035283