Re: What's the prerenderer do?

[Cyrille Chepelov <cyrille chepelov org>]

Le Sun, Mar 03, 2002, à 07:12:11PM -0600, Lars Clausen a écrit:

> It does?  In what way?  Gnus was warning me that there were more than two
> sections, but I could see them, neither when sending nor when seeing the
> mail on the list.

Well, the first section is your message's body in ISO-8859-15, and the
second one is your signature in ISO-8859-1. Which is funny, since both
sections could be encoded with both encodings... But it's a known fact that
Gnus is a bit weak on the auto-selection of the best encoding for a given
bit of text (I'm confident this'll be solved earlier than later. Saw some
things to that effect recently on debian-user-french l d o).

Funnily, mutt understands this is messy when I reply to your message, and
sees it can merge these sections. It'll then attempt sending in US-ASCII
first, then latin1, latin9, KOI8-R and if all else fails, UTF-8. Adding this
specific behaviour to Gnus is probably not that difficult.

> > Forget the DPS renderer. DPS on free *nix platforms is dead, even if
> > XFree 4 has swallowed some DPS stuff. Since the GYVE project more or less
> > died, nobody really uses it anymore. It was a nice experiment for me, but
> > it's a patch I haven't touched or maintained in... uh, let's say fourteen
> > months (no. It must be even more).
>
> Are there any files left from the DPS renderer that should be removed?

They've never been merged in the first place.


> I'm horribly confused about the unicode things.  I'm leaving the prolog
> stuff (mostly) alone now (except see below), so if you could fix these
> things, my brain and I would be most thankful:)  I'm thinking the FreeType
> version can be simple than the GDK version.
>
> I haven't yet gotten even close to dumping single glyph outlines, I simply
> dump the whole font.  I know it makes the file much larger, but it's a good
> first approximation and *much* easier.  To reduce the size, I shall (soon)
> have it use the standard PS fonts when possible.

OK. Be aware however that the very definition of "list of standard PS fonts"
is locale-dependent (actually, it depends on whether LC_ALL matches "ja_.*"
or not).

I'll give a try this evening at folding the StringPrerenderer into your
header pass. 

How hard would it be to do font dumping on a glyph basis ? Would it help if
I added the code which tracks of which glyph of which font is needed ?

> Here's a bit from the freetype mailing list:
>
>     > How do I find out a glyph index of characters>128 in TrueType Fonts
>     > when the character is not ASCII but in Latin2 or CP1250 codepage ?
>
>     The correct way is to activate a Unicode cmap (i.e. PID,EID=3,1), then
>     convert the character code of your encoding to Unicode, and finally
>     using FT_Get_Char_Index() to convert the Unicode encoded character into
>     a glyph index.
>
>
> This would happen in freetype_load_string() and freetype_render_string() in
> lib/font.c.  We may well want to just use the Unicode cmap for all fonts
> when Unicode is on, so in freetype_add_font(), add
>
>     FT_Select_Charmap(face, ft_encoding_unicode);
>
> for each face.  You know better than I how to convert chars into Unicode.

Converting one character to unicode is really easy: you just do something
like that:

for (utfchar* p = start; (*p); p = uni_next(p)) {
   unichar c;
   uni_get_utf8(p,&c);

   /* do something with c, which is an UCS-4 encoded Unicode character */
}

So yes, we definitely don't want to mess with FreeType and Microsoft's
vision of encoding maps, and just talk Unicode to these. We're very close to
always talking UTF-8 internally anyway.

        -- Cyrille

-- 
Grumpf.