[Cuis-dev] TrueType Fonts assignment

Juan Vuletich juan at jvuletich.org
Thu Apr 29 12:45:46 PDT 2021

On 4/29/2021 1:36 PM, stes--- via Cuis-dev wrote:
> I like the way Cuis is displaying _ as a left arrow.
> However this is not really TrueType or Unicode specific as I think it is precisely a remnant from "ancient fixed width terminal stuff", although on those ancient fixed width terminals you had not the choice of displaying left-arrow and underscore in a mixed way, as Cuis is doing.
> It's true that it's nice that Cuis is using context-dependant typography as underscore is allowed in variables or identifiers which was probably not possible on ancient fixed-width terminals although it may have been possible perhaps (but was of no use as perhaps early Smalltalk did not allow underscore in identifiers anyway?).
> According to some research that I did on this, because I do not use Smalltalk for such a long time,
> the left arrow is likely a remnant from early ASCII codemaps for terminals the so-called ASCII 1963.
> My guess is that the XEROX fixed-width terminals had the left-arrow and up-arrow characters as in ASCII 1963.
> https://en.wikipedia.org/wiki/ASCII
> the article on ASCII also mentions "left-arrow symbol (from ASCII-1963, which had this character instead of underscore)"
> Also, what I do remember, is that Commodore PET machines used a PET-ASCII which was a branch from ASCII 1963 with,
> up-arrow on the position of the caret ^ and left-arrow on the position of the underscore _.
> on the wikipedia article there is a screenshot of PRINT CHR$(94) and PRINT CHR$(95),
> and how it looked on old VIC-20 or Commodore-64 ancient fixed width fonts,
> indeed the Commodore-64 and VIC-20 have/had on the keyboard these symbols.
> The left-arrow is on the position of the 'ESC' left-top on the Commodore-64 and the up-arrow above-left of the return key.
> However, all of this is of course just to say that left-arrow was probably not unusual for character terminals,
> but the implementation of Cuis is nice because it maps this to Unicode/modern TrueType fonts.
> It can be done perfectly well with bitmap fonts and fixed-width terminals ... which is exactly where it comes from (ASCII 1963) I think.

Yes. It comes from ASCII '63. My TRS-80 CoCo is the same.

In Xerox, Smalltalk was implemented in the Alto computer (an 
experimental personal mini supercomputer), not in text mode terminals.

> In Squeak the StrikeFont (for bitmap fonts) which is also still in Cuis, has  messages
>    useLeftarrow
>    useUnderscore
> I tried it in plain Squeak 4.6 and there I can toggle with useLeftarrow and useUnderscore whether _ is displayed as left-arrow (as in Cuis) or as a plain underscore.

Yep. I built the antialiased StrikeFonts, including that code, for Cuis. 
Squeak and Pharo later adopted them. The smart selection of glyphs is 
only in Cuis, though.


Juan Vuletich

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