Re: What's the prerenderer do?

[Lars Clausen <lrclause cs uiuc edu>]

On Mon, 4 Mar 2002, Cyrille Chepelov wrote:
> 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).

Freaky.  I shall force it to ISO-8859-1.

>> 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).

Grumpf.  Is there some docs on this somewhere?

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

Goodie.

> 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 ?

That's the easy part.  The hard part is that we'd have to dump the font bit
by bit, instead of just copying the entire file.  It'd be a lot of work,
though I have some code references (xpdf, for instance).

>> 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 */
> }

Ok.  How do I test this, then?

-Lars

-- 
Lars Clausen (http://shasta.cs.uiuc.edu/~lrclause)| Hårdgrim of Numenor
"I do not agree with a word that you say, but I   |----------------------------
will defend to the death your right to say it."   | Where are we going, and
    --Evelyn Beatrice Hall paraphrasing Voltaire  | what's with the handbasket?