This is a placeholder topic for typographers that google the method of how to create CYRILLIC CAPITAL / SMALL LETTER I WITH GRAVE but don't know, like I didn't the name the FontLab team has assigned to this glyph in their program
1. Go to Wikipedia
2. Find the Symbol you are looking for, in this case CYRILLIC CAPITAL LETTER I WITH GRAVE
3. Copy the glyph from the Wikipedia website
4. In FontLab 8, open Font/Build Glyphs and paste the glyph
5.The Fontlab 8 "Build Glyphs" window should show you how the letter look and its unicode. The unicode you can also get from Wikipedia.
6. By clocking "OK", you can create the cell in FontLab for the glyphs and give it the shape that you like - it should be a И - Icyr + a grave accent.
7. You should be able to test the font by installing it and, on a QWERTY keyboard, using Shift+x to create ѝ. That x in the combination is a
Latin letter X,x, not a Cyrillic X, x.
ѝ is, in Bulgarian, a pronoun that means something like "her", "hers". For other uses, you can check
https://en.wikipedia.org/wiki/I_with_grave_(Cyrillic)
Comments
For the Cyrillic I with grave:
Please note that, if your font don't have the components (in this case, Cyrillic N and grave accent), FontLab will add an empty glyph, with proper encode. The same for new glyphs still not drawn.
FontLab 8 catalog includes all Unicode blocks.
The set of legacy spacing accents is small, and does not include many marks needed for non-Western European diacritics, so if one uses them in composites one ends up with a mixed approach of some spacing accents and some non-spacing combining marks. It is better practice to use a consistent model with non-spacing combining mark glyphs and anchor attachments. [Some tools, notably glyphs, confuse this somewhat, by having spacing combining mark glyphs attached with accents that then get their widths collapsed to zero during font export.]
Precomposed diacritic characters in Unicode mostly have canonical decompositions to base letters plus combining marks, so it makes sense to me that the precomposed composite glyphs in a font should be made from the same sequences of base + combining mark glyphs, which helps ensure that the display of precomposed and decomposed character sequences in different Unicode normalisation forms is the same.
[My standard practice is to use the combining marks as ingredient glyphs for the legacy spacing accents too, so e.g. /acute is a composite of /acutecomb on an advance width.]
Also – it doesn’t really matter for generated binaries in the case of OpenType CFF fonts where all components get converted to outlines.
You are right that this should be primarily an issue for font tool makers. Years ago, I told Georg that he should make combining marks the default components when creating diacritic composites, and he immediately got it (but Glyphs still has problems making zero-width glyphs selectable, hence the workaround to collapse widths during font export; I prefer the direct control in FontLab).