According to the SMuFL guidelines (and exemplified in Bravura), time signatures, figured bass symbols, tuplet numbers, function theory symbols and the likes are supposed to have zero width sidebearings. This means that all horizontal spacing has to be done with the use of kerning tables. I don’t know if extensive use of kerning will have a negative effect on the font, performance wise, or not, but from a font design perspective, kerning is a much more time consuming process than using regular metrics to set horizontal spacing.
I understand that, at least for time signatures and figured bass, these guidelines are supposed to ensure that characters are centred when stacked vertically. I also know that time signature numbers traditionally have been spaced with zero width sidebearings in music fonts. Even so, since these same characters also require considerations of horizontal spacing, I don’t think the guidelines in these specific cases are ideal.
Relatively even spacing on each side of the glyphs would also ensure good vertical spacing. A satisfactory result, then, depends more on uniformity in design and spacing of the glyphs in each category. However, it is certainly possible to design glyphs with both correct horizontal and vertical spacing without the (exclusive) use of kerning tables.
Would it be possible to make an exception to the rule of zero width sidebearings for these (and similar) kinds of number and text glyphs? It would really make the process of spacing a whole lot easier. In regards to function theory symbols, it’s less obvious why these should have zero width, so please enlighten me.
Locked
