[R] Plotting the ASCII character set.

[David Winsemius]

Sent from my iPhone

> On Jul 3, 2021, at 7:00 PM, Rolf Turner <r.turner using auckland.ac.nz> wrote:
> 
> 
>> On Sat, 3 Jul 2021 09:40:28 +0200
>> Ivan Krylov <krylov.r00t using gmail.com> wrote:
>> 
>> Hello Rolf Turner,
>> 
>> On Sat, 3 Jul 2021 14:02:59 +1200
>> Rolf Turner <r.turner using auckland.ac.nz> wrote:
>> 
>>> Can anyone suggest how I might get my plot_ascii() function working
>>> again?  Basically, it seems to me, the question is:  how do I
>>> persuade R to read in "\260" as "\ub0" rather than "\xb0"?
>> 
>> Part of the problem is that the "\xb0" byte is not in ASCII, which
>> covers only the lower half of possible 8-bit bytes. I guess that the
>> strings containing bytes with highest bit set used to be interpreted
>> as Latin-1 on your machine, but now get interpreted as UTF-8, which
>> changes their meaning (in UTF-8, the highest bit being set indicates
>> that there will be more bytes to follow, making the string invalid if
>> there is none).
>> 
>> The good news is, since it's Latin-1, which is natively supported by
>> R, there are even multiple options:
>> 
>> 1. Mark the string as Latin-1 by setting Encoding(a) <- 'latin1' and
>> let R do the re-encoding if and when Pango asks it for a UTF-8-encoded
>> string.
>> 
>> 2. Decode Latin-1 into the locale encoding by using iconv(a, 'latin1',
>> '') (or set the third parameter to 'UTF-8', which would give almost
>> the same result on a machine with a UTF-8 locale). The result is,
>> again, a string where Encoding(a) matches the truth. Explicitly
>> setting UTF-8 may be preferable on Windows machines running pre-UCRT
>> builds of R where the locale encoding may not contain all Latin-1
>> characters, but that's not a problem for you, as far as I know.
>> 
>> For any encoding other than Latin-1 or UTF-8, option (2) is still
>> valid.
>> 
>> I have verified that your example works on my GNU/Linux system with a
>> UTF-8 locale if I use either option.
> 
> Thanks Ivan. That solves most of the problem, but there are still
> glitches. I get a plot OK, but a substantial number of the characters
> are displayed as a wee rectangle containing a 2 x 2 array of digits
> such as
> 
>>  0 0
>>  8 0
> 
> Also note that there is a bit of difference between the results of using
> Encoding() and the results of using iconv(). E.g. if I do
> 
> a <- "\x80"
> b <- iconv(a,"latin1","UTF-8")
> Encoding(a) <- "latin1"
> 
> then when I type "a" I get the Euro symbol "€", but when I type "b"
> I get the string "\u0080".
> 
> But that doesn't really matter.  More problematic is the fact that if I
> do either
> 
>    plot(0,0,type="n",xlim=c(0,1),ylim=c(0,1),ann=FALSE,axes=FALSE)
>    text(0.5,0.5,labels=a,cex=6)
> or
> 
>    plot(0,0,type="n",xlim=c(0,1),ylim=c(0,1),ann=FALSE,axes=FALSE)
>    text(0.5,0.5,labels=b,cex=6)
> 
> then I get wee rectangle with 0 0 8 0 arranged in a 2 x 2 array inside.
> (Setting cex=6 makes it easier for my ageing eyes to see what the
> mAxdigits are.)
> 
> E Is hethere any way that I can get the Euro symbol to display correctly in
> such a graphic?
> 
Pick a font that is supported on your OS that has the desired glyph. 
Also look at the examples in:

?points

— 
David 
> Thanks.
> 
> cheers,
> 
> Rolf
> 
> -- 
> Honorary Research Fellow
> Department of Statistics
> University of Auckland
> Phone: +64-9-373-7599 ext. 88276
> 
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