Reinhard Hahn writes : Please record the following as an enhancement request.

A quite commonly used notation for augmented steps is to draw a line through the eventually elongated last line of the digit. In this case "Last line" refers to the order the digit is written manually. This results in a typographic ligature of the digit together with a plus sign.

In case of the augmented sixth the result should be like the following example http://de.wikipedia.org/w/index.php?title=Datei:Altsext.gif&filetimestamp=20090401171647 This is better readable then the result of the following snippet

\version "2.12.3" \figures { < 6\ >4 }

Similar should be possible together with the figures 2,4,5. Here the resulting plus sign isn't rotated but its is lowered or highered with respect to the result of

\version "2.12.3" \figures { \set figuredBassPlusDirection = #RIGHT < 5+ 4+ 2+ >4 }

A poor graphical representation is given in http://www.robertkelleyphd.com/FiguredBass.pdf where the vertical position is o.k., but it's not really a ligature.

It is quite obvious that the result may be depending on the font used for the digits.

A possible notation might be to use the + modifier and switch between the current and the intended behaviour with a property (e.g. \set figuredBassPlusLigature = #TRUE)

Despite my lack of metafont knowledge, I have started tweaking some of the glyphs: http://codereview.appspot.com/5683051

Please note: That patch is not yet ready for review, it is simply to show some ideas, which need to be improved a lot!

That patch simply takes the digits 2, 4 and 5 of the feta font, stretches the one line that will be slashed, and adds a vertical box as a slash through it. These glyphs are not yet used by the figured bass formatting functions, but you can already use them via the musicglyph markup function. Attached is a simple test file showing the glyphs.

Some issues: -) I have no idea how to properly implement the 6+ (the upper arc should have much less curvature and the slash is drawn through it. I would like the flare to have less turning angle, but with beta != +-90 it is no circle any more). -) Currently I place the slashes at more or less hardcoded positions and they are straight vertical. In particular for the 2 it might make sense to calculate the real intersection of the slash with the lower wavy line, so the slash is vertically centered. It might also be slanted to be perpendicular to the line it slashes through. Similarly, I'm not sure if the 5 should get a slightly slanted slash... -) I have no idea whether I should adjust the height of the boxes to include the slash. -) etc.

It would be great if someone with more metafont knowledge could improve those issues.