On 10/2/2018 9:29 AM, Ulrike Fischer wrote:
Am Tue, 2 Oct 2018 06:55:02 +0200 schrieb luigi scarso:
For what do you reserve the space in the PUA?
http://www.pragma-ade.nl/general/manuals/fonts-mkiv.pdf
page 32 of the document :
As we already mentioned in a previous chapter, in ConTeXt we use
Unicode internally. This also means that fonts are organized this
way. By default the glyph representation of a Unicode character
sits in the same slot in the glyph table. All additional glyphs,
like ligatures or alternates are pushed in the private unicode
space. This is why in the lists shown in the figures the
ligatures have a private Unicode number.
Hm. To clarify. In xetex there is clear distinction between the slot
and unicode. \XeTeXglyph (slot) and \char (unicode) give different
output and \char actively uses the tounicode mapping of the font.
\font\test="[lmroman10-regular.otf]"
\test
\XeTeXglyph"7A
\char"7A
\bye
In luatex \char and \Uchar don't really care about unicode, even if
the font has tounicode=1 and tounicode entries, they access the char
by the hashed integer number.
they access the char in the characters table (where each character has
an index field so one can write a simple function that accesses it by
index; also, i assume that in xetex \char gives the character as known
to tex so if one input non-unicode one gets that)
So to get "unicode" the font loader has to sort the glyphs, index
unicode glyphs by their unicode code point, and assign "non-unicode"
glyphs numbers that don't interfere.
Did I got right?
indeed, and we use the private space for those with no unicode (which
can be a lot, also think for instance of the snippets that make up math
extensibles)
Then I do understand that you need some free numbers to push
glyphes. But I do not understand why to achieve this you remove
glyphs from their unicode points. The PUA is not some non-unicode
wilderness. The code points there are as valid as in the other code
blocks. You wouldn't move away the greek block to get the place, so
why do you think it is okay to throw out of the PUA block what SIL
and other font designers encoded there? Can't you check for a free
range instead?
sure, but then i also loose some functionality in context (unless i gho
for ugly solutions) ... as all glyphs are supposed to have a name access
by name is a pretty good alternative
the main issue is that there are fonts that use private > 0xFFFF space
which then would mean a lot of extra mem for names ... so the question
is are there fonts that use that range
Hans
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