Pictorial Representations of BS and DEL
lists+unicode at seantek.com
Fri Oct 9 13:32:38 CDT 2015
As we continue to riff on the history of character encodings, I am
searching for the most accurate standards-based pictorial
representations of BS (U+0008) and DEL (U+007F) in Unicode.
ECMA-17:1968 and ANSI X3.32-1973 depict U+0008 as an arrow pointing from
the bottom-right to the top-left, slightly arced upwards. They depict
U+007F as a filled box symbol comprised of five diagonal slashes
oriented from bottom-left to top-right, with no border.
All of the other control pictures (from those standards) have specific
code point assignments in Unicode. Whether those glyphs are used for
U+2400 et. seq. is, of course, up to the font designer. But it's nice to
know they are there as fallbacks.
What are the most accurate pictorial representations in the existing
Unicode Standard for BS and DEL?
Frankly there are so many arrows that it's hard to make heads or tails
(pun intended) out of which one is the best. However, in all the arrows
I looked for, I did not see one that was a sufficiently close match.
There is another standard governing these sorts of things, namely ISO
9995. I would not be surprised if it has something to say about
Backspace, as the Backspace keytop is standardized to look like:
Note that there are still many left-pointing arrows in the Unicode
standard, so which Unicode left-pointing arrow is the closest one to the
one typically printed on a keytop?
▨ U+25A8 SQUARE WITH UPPER RIGHT TO LOWER LEFT FILL is close, but it has
a black box border.
␥ U+2425 SYMBOL FOR DELETE FORM TWO is depicted as three slashes in the
middle, not five slashes, and is from ISO 9995-7. It is a symbol for
"undoable delete". I presume that the omission of the fourth and fifth
slashes is intentional.
⌂ U+2302 HOUSE is the corresponding grapheme in Code Page 437, and so
many people would probably be familiar with using this to depict U+007F.
But we are trying to bury Code Page 437.
(Note: this is relevant to the C1 control character CCH U+0094, which is
intended to eliminate ambiguity about the meaning of BS. Arguably ⌫
U+232B ERASE TO THE LEFT is the most appropriate for CCH, but it could
also be used for BS, and that is the problem because BS is more nebulous
but far, far more ubiquitous than CCH.)
More information about the Unicode