[coldtea]

>If I want to know how much memory to allocate, bytes are it. If I want to know how much screen space to allocate, font rendering metrics are it. If I want to do word-breaking, grapheme clusters are it.

Size in memory/bytes you could get trivially for any string (and this doesn't change with whether you chose bytes, graphemes or code points or whatever to iterate).

Screen space is irrelevant/orthogonal to encoding -- it appears at the font level and the font rendering engine that will give the metrics will accept whatever encoding it is.

[Retra]

>Screen space is irrelevant/orthogonal to encoding

Exactly. That's why measurements of string length shouldn't ever assume I'm looking for a unit-of-offset for a monospaced font.

The problem is that most naive programmers think that's what a string length is and should be.