satisfactorily fills simple closed curves, like `O' and `D', but filling a figure eight, `8', causes a complaint:
Strange path (turning number is zero)because 's rules for distinguishing inside from outside might or might not give what you want for an `8', as there is more than one conceivable answer. You can use the `positive turning rule' for all cases, and also turn off complaints, by setting
turningcheck := 0;Chapter 13: `Drawing, Filling, and Erasing', and Chapter 27: `Recovery from Errors', discuss strange paths in greater depth.
Sometimes, when making a perfectly valid font, but in low resolutions, as for previewers (eg, VGA has 96 dpi), one may get flak about a `Strange path' or `Not a cycle' or something similar. Don't be alarmed. Fonts for previewing will still be OK even if not perfect.
Consequently, it is an idea to make low resolution fonts in 's nonstopmode.
Examples of fonts that give messages of this nature are the pleasant Pandora, and — from memory — the commendable Ralf Smith's Formal Script (rsfs). Everything is fine at higher resolutions.
Mind you, some fonts provoke sporadic (that is, design size dependent) strange path messages at 300 dpi (phototypesetter users would consider that low resolution), yet the printed appearance showed no visible defect.
Why do strange paths occur? One cause is rounding error on relatively coarse grids.
To summarize, if your viewed or printed bitmaps are fine, then you are OK.