A One-Line (Single-line, Singl-stroke) font is special type of font wich uses one line to define the shape of each character-glyph.
This font is used for CNC machines, CNC laser, Ploters, Sawing machines etc, where letters are used.
This font
dose not have a defined thickness, it defines the path of movement of tools, lasers, machines.
One-Line fonts cannot
write correctly in programs like Adobe Illustrator, AutoCAD, CorelDRAW etc.
That is the reason why this font is not generated as as it was not generated-made as .ttf or .otf font.
One-line font can be made in special font formats and theirs fonts editors such as:
.CHR (Borland); .shx (AutoCAD); .LZ2 (Lang); .CAR (Gravograph); .eff (infoFORM) etc.
Standard fonts are closed two line fonts
in whose surface beatwin this two line represent leters.
------------
Perhaps it is best to look at the page about One-Line fonts on our Engraving Portal
more than 15 years old, which should have been upgrade a long time ago,
but many interesting things can be seen there.
https://graviranje.rs/Engraving_PORTAL/fonts/One_Line_Fonts.htm
------------
Development our Orach Technic font is started 35 years ago, due to the lack of multilingual single line font.
It was possible to engrave
text: Latin, Cyrillic, Greek, Arab in the same still, or at last corretly,
after all, it is not posible even today 2022.
In the late 80s, to make these font we had to make
Orach Engraving Software, Orach Font Editor and only then Orach One Line font
in .eff (Engraving Font Format), all in Borland-C on Win 3.11.