Private Use Area characters and the eudcedit program

[Jim DeLaHunt]

On 2024-02-02 14:33, William_J_G Overington via Unicode wrote:

> Regarding the issue raised in the thread
>
> https://forum.affinity.serif.com/index.php?/topic/197938-private-characters-created-with-microsoft-eudceditexe 
>
The issue appears to be (copying text from that thread to this):
> I have created two "private" characters using the Windows built-in 
> eudcedit utility. The first one I have saved to a specific font and 
> the second one I have saved to all fonts.
>
> I can locate and copy both characters in Character Map and paste them 
> successfully into Notepad and into my CAD programs, but not Affinity 
> Publisher (v.1)  Is there a special procedure in Publisher that will 
> overcome this, or is the programe not yet equipped to deal with 
> private characters?
>

On 2024-02-02 14:33, William_J_G Overington via Unicode wrote:

> can anyone explain what is happening please?

I can perhaps shed some light, if not explain definitively.

Anyone using EUDCedit would be well advised to learn what Windows has to 
say about what EUDC is and how it works in Windows. A web search finds:

*End-User-Defined and Private Use Area Characters* (2021) 
<https://learn.microsoft.com/en-us/windows/win32/intl/end-user-defined-characters>

> End-user-defined characters (EUDC) in double-byte character sets 
> <https://learn.microsoft.com/en-us/windows/win32/intl/double-byte-character-sets> 
> (DBCSs) and private use area (PUA) characters in Unicode 
> <https://learn.microsoft.com/en-us/windows/win32/intl/unicode> are 
> custom characters. They can be defined and implemented either by an 
> end user or by another party…. Their use enables users to form names 
> and other words using characters that are not available in standard 
> screen and printer fonts.
>
> The EUDC and PUA characters can be assigned differently, or not 
> assigned at all, on different computers. Some code pages have 
> extensions that reuse the EUDC range, … a manufacturer might provide a 
> custom set of characters in one of these ranges, … user groups can 
> attempt to provide additional characters in the PUA. Different 
> combinations of these cases can cause conflict. When creating 
> applications that rely on EUDC or PUA characters, you should keep in 
> mind the conflicting interpretations of an individual code point.…
>

*Character Sets and Fonts* (2021) 
<https://learn.microsoft.com/en-us/windows/win32/intl/character-sets-and-fonts>

> To create an EUDC or PUA character, the user chooses a character value 
> that is within the specified range and adds the glyph 
> <https://learn.microsoft.com/en-us/windows/win32/intl/uniscribe-glossary> 
> to the font in the entry that corresponds to that character value. The 
> user creates the glyph using an EUDC editor or using a font package 
> purchased from a font vendor. Any DBCS font can contain EUDCs, and any 
> Unicode font can contain PUA characters. The font is called a 
> "separate" EUDC/PUA font if it contains only EUDCs. The font is an 
> "integrated" EUDC/PUA font if it contains standard characters as well 
> as EUDCs.…
> TrueType fonts can be installed either as .ttf files or as .tte files. 
> Since the operating system hides .tte files, applications cannot 
> enumerate or otherwise examine the installed fonts using GDI API 
> functions. On many operating systems, the system default EUDC/PUA font 
> and separate EUDC/PUA fonts are installed as .tte files. Applications 
> such as EUDC editors and the Control Panel must use registry entries 
> to add, modify, and delete such fonts.…


The backstory is that end-user defined character handling is a text 
requirement originating from ideographic scripts, especially Japan, and 
an era when the glyph complement of Japanese fonts was small (c 5,000 
glyphs) compared to the range of ideographic characters listed in 
dictionaries and fair game to use in text (c 70,000 characters). Authors 
wanting to use such "outside characters" (known as "gaiji" in Japanese) 
in their publications had to resort to special measures like EUDCs. OS 
and application vendors who wanted to sell to serious publishers in the 
Japanese market need to provide EUDC tools.

The need for special measures like EUDC has receded greatly with the 
arrival of ideographic script fonts with very large glyph repertoires. 
Use of EUDC tools in ideographic script documents is likely now a niche. 
Use of EUDC outside of ideographic script context is even more of a niche.

The original question was, "I can [not] locate and copy [my EUDC] 
characters in… Affinity Publisher (v.1)  Is … the programe not yet 
equipped to deal with private characters?"

It seems pretty likely to me that the program is not equipped to deal 
with EUDC characters. The feature list for Affinity Publisher 
<https://affinity.serif.com/en-us/publisher/full-feature-list/> does not 
mention Japanese or Chinese typography support. If they do not have 
ideographic typography as a major feature, they are even more unlikely 
to have Windows-specific EUDC support.

-- 
.   --Jim DeLaHunt,jdlh at jdlh.com      http://blog.jdlh.com/  (http://jdlh.com/)
       multilingual websites consultant, Vancouver, B.C., Canada
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