[pdftex] pdftex - Encoding for metafont PK fonts
vojta at math.berkeley.edu
Sat Jun 25 22:52:23 CEST 2016
On Sat, Jun 25, 2016 at 12:46:06PM +0200, Pali Rohár wrote:
> On Friday 24 June 2016 23:10:04 Paul Vojta wrote:
> > For PK fonts as produced by MetaFont (which are not PS Type 3),
> > probably the way to go would be to create a virtual font to achieve
> > the reencoding. That is the standard way to go in the dvi driver
> > world.
> So e.g. when I select character 'č' PDF reader copy 'è'. 'č' is at
> position 0xE8 in Latin2 and at position 0xE8 in Latin1 is 'è'.
I presume that your character 'č' is U+010D (LATIN SMALL LETTER C WITH
CARON), which is not in the range 0-255. So, given your comments below,
virtual fonts would not be able to support this character.
> Maybe PDF readers could think that font is not in Latin1, but in Unicode
> as IIRC Unicode at positions 128-255 have same characters as Latin1
> Unicode character U+00E8 is for sure 'è'. So I bet this is reason why
> PDF reader thinks that I selected character 'è' and not 'č'.
> For Type 1 PFB fonts (even in IL2 encoding) this is not a problem,
> because for each characters there is stored unified glyph name and there
> is standard conversion table from glyph name to unicode character.
> So probably in PK fonts is not any conversion table from 8bit character
> to unicode character and so something (pdftex? PDF reader?) assume
> either Latin1 or Unicode.
Yes, I agree that this is likely the case. I do know that in PK fonts,
there is only a character (or no character) for each of the positions 0-255,
with no character names or additional coding information.
> In detail my question is: How to tell pdftex encoding of PK font
> (generated from MetaFont)?
> > For information on virtual fonts: use Google.
> With above detailed description, are you sure that virtual fonts could
> do this unicode mapping?
> Are not virtual fonts again only 8bit (as opposite of glyph names and
Yes, virtual fonts are only 8 bits. There are things called "omega
virtual fonts" which I think allow for larger-numbered characters,
but I don't know whether pdftex supports them. I think that luatex does.
Paul Vojta, vojta at math.berkeley.edu
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