Slur does not begin or end on stem

[arshiacont]

This is a pattern that appears often.

Take the following snippet and watch Slur behavior where they do not start or end on the stem end:

{[
   (* meas. 1 *)  \clef<"g2">  \meter<"C"> \stemsUp {c/4, e/4, g/4  } {c/8, e/8, g/8  } {c/8, e/8, g/8  } 
   \slurBegin:1<curve="up"> {f/8., a/8.  } {e/16, g/16  } f/4 \slurEnd:1 \bar 
   (* meas. 2 *) 
   \slurBegin:1<curve="up"> c2/4 {e1/8, b&/8} {f/8, a/8  } \slurEnd:1 \slurBegin:1<curve="up">  
   g/4. \stemsUp \beamsOff \acc( g#/8)
 \slurEnd:1 \bar 
   (* meas. 3 *)  \slurBegin:1<curve="up"> a/4 \stemsUp \beamsOff {e/4, g/4  } \slurEnd:1 \slurBegin:1<curve="up"> \beamBegin:1 {a0/8, f1/8  } c/8 {a0/8, f1/8  } c2/8 \slurEnd:1 \beamEnd:1 ]
  }

[arshiacont]

This might be related to #87

[dfober]

This might be related to #87

I think so too.
Did you notice that when removing the <curve="up">, you'll get a correct result?
The problem here is that the slur is underspecified, generally when enforcing a direction, additional dy parameters are also required.
But I understand your point, which is however beyond the initial engine design. I think that could be solved but I'm afraid it's a serious investment. I'll have a look asap (which means in a long time now)

[arshiacont]

Good to know!

All the scores I sent are MusicXML conversions. I simplified the score for the purpose of bug reporting. In the full score, there are multiple voices and that's why there is a Curve direction. If I remove the <curve="up"> it'll be drawn on the bottom and colliding with other voices.

I'll try to dig into the implementation of the Slur in Guido and compare with others to see whether there are simple things to do.

[arshiacont]

In case it helps for unit tests, this is another incarnation of the same problem but this time on a cross-staff.. :

{[ \staff<1> \accol<id=0, range="1-2"> \barFormat<style= "system", range="1-2"> 
   (* meas. 1 *)  \clef<"g2"> \key<-1> \meter<"2/4", autoBarlines="off", autoMeasuresNum="system">  
\tuplet<"", dispNote="/16">( \restFormat<dy=19>( _/24)
 \staff<2> \stemsUp \slurBegin:1<curve="up"> \beamBegin:1 \beamBegin:2 e0/24 \stemsUp d1/24)
 \beamEnd:2 \beamEnd:1 \stemsUp \beamBegin:1 \beamBegin:2 \tuplet<"", dispNote="/16">( \acc( b0/24)
 \staff<1> \stemsUp e1/24 d/24)
 \beamEnd:2 \beamEnd:1 \acc( b/8)
 \slurEnd:1 _/8 \bar 
   (* meas. 2 *)  \tuplet<"", dispNote="/16">( \restFormat<dy=16>( _/24)
 \staff<2> \stemsUp \slurBegin:1<curve="up"> \beamBegin:1 \beamBegin:2 e0/24 \stemsUp c1/24)
 \beamEnd:2 \beamEnd:1 \stemsUp \beamBegin:1 \beamBegin:2 \tuplet<"", dispNote="/16">( a0/24 \staff<1> \stemsUp e1/24  c/24)
 \beamEnd:2 \beamEnd:1 \stemsUp \beamsOff a/8 \slurEnd:1 _/8 \bar 
   (* meas. 3 *)  \tuplet<"", dispNote="/16">( \restFormat<dy=17>( _/24)
 \staff<2> \stemsUp \slurBegin:1<curve="up"> \beamBegin:1 \beamBegin:2 \acc( e&0/24)
 \stemsUp c1/24)
 \beamEnd:2 \beamEnd:1 \stemsUp \beamBegin:1 \beamBegin:2 \tuplet<"", dispNote="/16">( a0/24 \staff<1> \stemsUp \acc( e&1/24) c/24)
 \beamEnd:2 \beamEnd:1 \stemsUp \beamsOff a/8 \slurEnd:1 _/8 \bar 
   (* meas. 4 *)  \tuplet<"", dispNote="/16">( \restFormat<dy=15>( _/24)
 \staff<2> \stemsUp \slurBegin:1<curve="up"> \beamBegin:1 \beamBegin:2 \acc( e0/24)
 \stemsUp c1/24)
 \beamEnd:2 \beamEnd:1 \stemsUp \beamBegin:1 \beamBegin:2 \tuplet<"", dispNote="/16">( g0/24 \staff<1> \stemsUp \acc( e1/24) c/24)
 \beamEnd:2 \beamEnd:1 g/8 \slurEnd:1 _/8 ]
 , 
[ \staff<2>
   (* meas. 1 *)  \clef<"f4"> \key<-1> \meter<"2/4", autoBarlines="off", autoMeasuresNum="system"> 
   \stemsDown \beamsOff {\acc( g#-2/2)
, \acc( g#-1/2)
  } \bar 
   (* meas. 2 *)  \stemsDown {a-2/2, a-1/2  } \bar 
   (* meas. 3 *)  \stemsDown {\acc( f#-2/2)
, \acc( f#-1/2)
  } \bar 
   (* meas. 4 *)  \stemsDown {g-2/2, g-1/2  } ]
  }

[dfober]

fixed (and pushed)