[smufl-discuss] Re: Notehead Metrics

[Laurent Pugin]

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?
>
>
> For reference, my testing was in using SVG graphics within the Firefox web
> browser on Windows. The other Windows browsers seem to produce similar
> results, although only Firefox properly handled the vertical positioning
> ligatures of the BravuraText font. All of them (Firefox, Opera, Chrome) can
> handle the Bravura font, positioned with SVG graphics. Internet Explorer
> seems to have some issues with certain operations of SVG graphics, so it
> produces somewhat bizarre results at some zoom factors. I'm not sure what
> internal precision Firefox uses for its graphics.
>
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