[Fontconfig] Searching by PostScript FontName

[mpsuzuki at hiroshima-u.ac.jp]

Hi,

On Thu, 02 Aug 2007 23:25:30 -0700
Sairus Patel <sppatel at adobe.com> wrote:
>What would be involved if I wanted to enumerate or search fonts by 
>PostScript FontName (OT 'name' table ID 6)?

Yet I'm not sure if I'm understanding what you want,
please check FcFreeTypeQueryFace() function implemented
by fontconfig-x.y.z/src/fcfreetype.c. It opens the font
face (the font file is already opened, and FreeType2's
"face" object is passed to this function) and it gets
some properties by calling FreeType2 library, and it
summarizes the properties. Here I quote fontconfig-2.4.2.

  1065  FcPattern *
  1066  FcFreeTypeQueryFace (const FT_Face  face,
  1067                       const FcChar8  *file,
  1068                       int            id,
  1069                       FcBlanks       *blanks)
  1070  {
...
  1145      snamec = FT_Get_Sfnt_Name_Count (face);
  1146      for (p = 0; p <= NUM_PLATFORM_ORDER; p++)
  1147      {
...
  1157          for (n = 0; n < NUM_NAMEID_ORDER; n++)
  1158          {
  1159              nameid = nameid_order[n];
  1160  
  1161              for (snamei = 0; snamei < snamec; snamei++)
  1162              {
...
  1197  
  1198                  switch (sname.name_id) {
  1199                  case TT_NAME_ID_PREFERRED_FAMILY:
  1200                  case TT_NAME_ID_FONT_FAMILY:
  1201  #if 0       
  1202                  case TT_NAME_ID_PS_NAME:
  1203                  case TT_NAME_ID_UNIQUE_ID:
  1204  #endif
  1205                      if (FcDebug () & FC_DBG_SCANV)
  1206                          printf ("found family (n %2d p %d e %d l 0x%04x) %s\n",
  1207                                  sname.name_id, sname.platform_id,
  1208                                  sname.encoding_id, sname.language_id,
  1209                                  utf8);
  1210  
  1211                      elt = FC_FAMILY;
  1212                      eltlang = FC_FAMILYLANG;
  1213                      np = &nfamily;
  1214                      nlangp = &nfamily_lang;
  1215                      break;
...
  1242                  case TT_NAME_ID_TRADEMARK:
  1243                  case TT_NAME_ID_MANUFACTURER:
  1244                      /* If the foundry wasn't found in the OS/2 table, look here */
  1245                      if(!foundry)
  1246                          foundry = FcNoticeFoundry((FT_String *) utf8);
  1247                      break;
  1248                  }
  1249                  if (elt)
  1250                  {
  1251                      if (FcStringInPatternElement (pat, elt, utf8))
  1252                      {
  1253                          free (utf8);
  1254                          continue;
  1255                      }
  1256  
  1257                      /* add new element */
  1258                      if (!FcPatternAddString (pat, elt, utf8))
  1259                      {
  1260                          free (utf8);
  1261                          goto bail1;
  1262                      }
  1263                      free (utf8);
...

Here, as you can find, PS font name is parsed (if it's
written in the font file and FreeType2 can read it),
but not stored in FcPattern (the summary of properties
which fontconfig can handle).

>a. enumerate all font file paths
>b. read in the sfnt/TTC myself to get to the name table
>c. then parse the name table to get to the PostScript FontName
>
>Questions:
>1. Is there a more direct way to do any or all of these steps that 
>I'm missing? I can't seem to find a PostScript FontName property at
>http://fontconfig.org/fontconfig-devel/x19.html#AEN27 and searching 
>the mailing list archives didn't help.

If you're not asking for the enhancement of fontconfig
to store PS FontName, you are not missing anything.

>2. Can FontConfig at least do step (b) for me, i.e. can I ask it to 
>get me a particular table from the sfnt/TTC? Or is the idea that 
>FontConfig can provide the full path to the font file, and from there 
>on clients are on their own if they want to do interesting stuff with 
>the font that FontConfig doesn't support?

Once the full path to font file is resolved, using FreeType2
is easy to open a font file, get a face in it, and parse name
table. I guess, fontconfig is expected to handle any font
file that FreeType2 supports, but the summarization of font
properties in fontconfig is not appropriate for some bitmap
fonts. I'm not sure what you mean by "FontConfig doesn't support",
I wish you give any concrete example.

>3. For Type 1 fonts, I'd have to replace (b) and (c) above with 
>simply parsing the font file directly, right?

I think most Type1 fonts can be parsed by FreeType2.

Regards,
mpsuzuki