[smufl-discuss] Re: Notehead Metrics

[Glenn Linderman]

Thanks for the response, Laurent, but that thread seems to be discussing
that the sizes of the various noteheads are different than each other. I
expected that, but my issues, summarized, are that:

The attachment points for stems to the most common noteheads seem to be
somewhat inaccurate or imprecise, and that noteheads can exceed the
height of a staff space even at small font sizes, but at large font
sizes the effect is enlarged.


On 12/23/2014 3:07 AM, Laurent Pugin wrote:

> Hi,
>
> I am not sure this is the same topic but I have the impression it was
> already discussed here :
> http://smufl-discuss.50501.x6.nabble.com/smufl-discuss-Re-Note-head-height-tt416.html
>
> Laurent
>
> On Sun, Dec 21, 2014 at 4:15 AM, Glenn Linderman <[hidden email]> wrote:
>> Hi Daniel,
>>
>> Not sure if my note regarding the suggestion for a unison whole notehead
>> came through.
>>
>> But this note has a different purpose, to discuss the metrics for stem
>> attachment. Now I'm a programmer, not a font designer, so I don't know much
>> about how you figured out the numbers for the stem attachments, or whether
>> those points are specifically end points on the Bézier curves, or just
>> calculated to be tangent to the curves... in which case they could appear to
>> move around a bit at different resolutions.
>>
>> So if I properly created a formula from your instructions, given the point
>> of placement of the note ( X, Y ) I should place the SW point of an upward
>> stem at:
>>
>> ( X + stemUpSE[0] - stemThickess,  Y + stemUpSE[1] )
>>
>>
>> When I did so, at larger sizes, it protruded awkwardly from the note. So I
>> "fiddled around" with the stemUpSE[0] numbers, until I got a stem that was
>> tangent to the note at the attachment point.
>>
>> For noteheadHalf, this was 1.478, and for noteheadBlack, this was 1.443. The
>> Bravura metadata file suggests 1.364 and 1.328, respectively, with the
>> differences being .114 and .115, respectively. This is suspiciously close to
>> the stemThickness of .12, making me wonder if you accidentally put StemUpSW
>> values in the chart instead of StemUpSE values, as the chart is labeled.
>> These are the only noteheads I've experimented with so far, so I can't say
>> much in general terms, just these specific noteheads. Using your numbers as
>> StemUpSW values would work pretty well for small notes, but for
>> screen-filling notes, the values I determined empirically work well for
>> screen fonts from 10-2560pt.
>>
>> Since screens are 96dpi and typesetters are around 2400dpi, this covers
>> typesetting up to 102pt... that'd be a large print edition!
>>
>> I didn't test sizes between 2560 and 5120, but a spotcheck of 5120pt size,
>> my numbers produce stems that are well inside the notehead boundaries :( So
>> likely higher precision numbers (more than 3 digits to the right of the
>> decimal point) would be required to scale that high.
>>
>>
>> This raises my second question. While you recommend a staffLineThickness of
>> .13, I was experimenting with a staffLineThickness of .1, and even at
>> smaller zoom factors (anything above 17pt @96dpi) was noticing a little
>> protrusion of the notes both above and below the staff lines surrounding the
>> space they are sitting in.  Should the notes not be constrained to the
>> center point of the stafflines (or slightly less), rather than exceeding the
>> center points?

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