R devel - Mar 2020 - Plotmath on Fedora 31 broken with with pango >= 1.44 - workarounds?

Le lundi 30 mars 2020 ? 15:24 +1300, Paul Murrell a ?crit
:
> Hi
> 
> I have created an R branch that contains a potential fix ...
> 
> https://svn.r-project.org/R/branches/R-symfam/
> 
> This allows, for example, ...
> 
> cairo_pdf(symbolfamily="OpenSymbol")
> 
> ... to specify that the OpenSymbol family should be used as the
> "symbol" font (e.g., for "plotmath") in R.
Thanks for looking at it!

But, really, there is no such thing as a Symbol font on Linux anymore.
Symbol is pre-unicode thinking. Most modern general-purpose unicode
fonts will include every codepoint Symbol ever shipped, and fontconfig
will fallback gracefully when that?s not the case (unless your
fontconfig integration is broken).

Just use the sans-serif or monospace fontconfig defaults. You don?t
need Symbol, or OpenSymbol, or any special font setup.

Symbol?s codepoint coverage is laughable by 2020?s UTF-8 standards.

Symbol << Normal Unicode font (DejaVu*) << Special math fonts
(STIX2)

I you do advanced math stuff, you may need a special math font like
STIX, but that?s lights years more advanced than Symbol, and a general
purpose font like DejaVu has been shipping a MATH block for several
years now

Regards,

-- 
Nicolas Mailhot

Hi

On 30/03/20 11:12 pm, Nicolas Mailhot wrote:
> Le lundi 30 mars 2020 ? 15:24 +1300, Paul Murrell a ?crit :
>> Hi
>>
>> I have created an R branch that contains a potential fix ...
>>
>> https://svn.r-project.org/R/branches/R-symfam/
>>
>> This allows, for example, ...
>>
>> cairo_pdf(symbolfamily="OpenSymbol")
>>
>> ... to specify that the OpenSymbol family should be used as the
>> "symbol" font (e.g., for "plotmath") in R.
> 
> Thanks for looking at it!
> 
> But, really, there is no such thing as a Symbol font on Linux anymore.
> Symbol is pre-unicode thinking. Most modern general-purpose unicode
> fonts will include every codepoint Symbol ever shipped, and fontconfig
> will fallback gracefully when that?s not the case (unless your
> fontconfig integration is broken).
Yep, the "symbol" font is an (outdated) R "plotmath"
concept, but one
that would take a fair bit of surgery to remove.  R plotmath converts 
certain R expressions (in certain contexts) to code points in the Adobe 
Symbol Encoding (ASM), but for cairo-based devices, those are converted 
to UTF8 code points.
> Just use the sans-serif or monospace fontconfig defaults. You don?t
> need Symbol, or OpenSymbol, or any special font setup.
Agreed.  I got reasonable coverage from DejaVu Sans and FreeSerif. 
There are still a number of ASM code points that are not covered though, 
for example, ...

F8EB	E6	# LEFT PAREN TOP	# parenlefttp (CUS)
F8EC	E7	# LEFT PAREN EXTENDER	# parenleftex (CUS)
F8ED	E8	# LEFT PAREN BOTTOM	# parenleftbt (CUS)

Even OpenSymbol is missing a few (though perhaps not very common ones) ...

F8E5	60	# RADICAL EXTENDER	# radicalex (CUS)
F8E6	BD	# VERTICAL ARROW EXTENDER	# arrowvertex (CUS)
F8E7	BE	# HORIZONTAL ARROW EXTENDER	# arrowhorizex (CUS)
F6DA	D2	# REGISTERED SIGN SERIF	# registerserif (CUS)
F6D9	D3	# COPYRIGHT SIGN SERIF	# copyrightserif (CUS)
F6DB	D4	# TRADE MARK SIGN SERIF	# trademarkserif (CUS)
F8E8	E2	# REGISTERED SIGN SANS SERIF	# registersans (CUS)
F8E9	E3	# COPYRIGHT SIGN SANS SERIF	# copyrightsans (CUS)
F8EA	E4	# TRADE MARK SIGN SANS SERIF	# trademarksans (CUS)
> Symbol?s codepoint coverage is laughable by 2020?s UTF-8 standards.
Right, but there are still code points that are apparently not common in 
fonts with a very broad Unicode coverage.

I did find a TrueType font that I could add a Unicode cmap to that gave 
complete coverage pretty much all by itself, but it is not distributable.
> Symbol << Normal Unicode font (DejaVu*) << Special math fonts
(STIX2)
> 
> I you do advanced math stuff, you may need a special math font like
> STIX, but that?s lights years more advanced than Symbol, and a general
> purpose font like DejaVu has been shipping a MATH block for several
> years now
Sure.  One way to look at the new 'symbolfamily' argument is that it 
allows us to tell R that the "symbol" font is just a normal font (for 
cairo-based graphics devices).

Paul
-- 
Dr Paul Murrell
Department of Statistics
The University of Auckland
Private Bag 92019
Auckland
New Zealand
64 9 3737599 x85392
paul at stat.auckland.ac.nz
http://www.stat.auckland.ac.nz/~paul/

Le mardi 31 mars 2020 ? 10:14 +1300, Paul Murrell a ?crit
:
> Hi
> 
> On 30/03/20 11:12 pm, Nicolas Mailhot wrote:
> > Le lundi 30 mars 2020 ? 15:24 +1300, Paul Murrell a ?crit :
> > > Hi
> > > 
> > > I have created an R branch that contains a potential fix ...
> > > 
> > > https://svn.r-project.org/R/branches/R-symfam/
> > > 
> > > This allows, for example, ...
> > > 
> > > cairo_pdf(symbolfamily="OpenSymbol")
> > > 
> > > ... to specify that the OpenSymbol family should be used as the
> > > "symbol" font (e.g., for "plotmath") in R.
> > 
> > Thanks for looking at it!
> > 
> > But, really, there is no such thing as a Symbol font on Linux
> > anymore.
> > Symbol is pre-unicode thinking. Most modern general-purpose unicode
> > fonts will include every codepoint Symbol ever shipped, and
> > fontconfig
> > will fallback gracefully when that?s not the case (unless your
> > fontconfig integration is broken).
> 
> Yep, the "symbol" font is an (outdated) R "plotmath"
concept, but
> one 
> that would take a fair bit of surgery to remove.  R plotmath
> converts 
> certain R expressions (in certain contexts) to code points in the
> Adobe 
> Symbol Encoding (ASM), but for cairo-based devices, those are
> converted 
> to UTF8 code points.
> 
> > Just use the sans-serif or monospace fontconfig defaults. You don?t
> > need Symbol, or OpenSymbol, or any special font setup.
> 
> Agreed.  I got reasonable coverage from DejaVu Sans and FreeSerif. 
> There are still a number of ASM code points that are not covered
> though, 
> for example, ...
> 
> F8EB	E6	# LEFT PAREN TOP	# parenlefttp (CUS)
> F8EC	E7	# LEFT PAREN EXTENDER	# parenleftex (CUS)
> F8ED	E8	# LEFT PAREN BOTTOM	# parenleftbt (CUS)
> 
> Even OpenSymbol is missing a few (though perhaps not very common
> ones) ...
All the F8* codepoints are in the private use area. That means you
can?t rely on them existing in standard unicode fonts

You need to use correct Unicode values for things to work:
Ux239? for parenthesis, brackets

https://www.unicode.org/charts/PDF/U2300.pdf
> F8E6    BD      # VERTICAL ARROW EXTENDER       # arrowvertex (CUS)
> F8E7    BE      # HORIZONTAL ARROW EXTENDER     # arrowhorizex (CUS)
and 23AF/23D0 for arrow extensions (though arrow font support seems
messy, probably because it sees little use; it?s a pity R comes so late
to the party, those are just lines, it would have been trivial to get
them into DejaVu before the project gone dormant). GFS NeoHellenic
(Math block) seems complete but it?s not a common font family.
> F6DA    D2      # REGISTERED SIGN SERIF # registerserif (CUS)
> F6D9    D3      # COPYRIGHT SIGN SERIF  # copyrightserif (CUS)
> F6DB    D4      # TRADE MARK SIGN SERIF # trademarkserif (CUS)
> F8E8    E2      # REGISTERED SIGN SANS SERIF    # registersans (CUS)
> F8E9    E3      # COPYRIGHT SIGN SANS SERIF     # copyrightsans (CUS)
> F8EA    E4      # TRADE MARK SIGN SANS SERIF    # trademarksans (CUS)
Those are useless nowadays, just use normal
registered/copyright/trademark codepoints, and a font in the wished
style (serif sans serif, whatever looks nice to you)

Regards

-- 
Nicolas Mailhot