def create_unicode_map(self):
if 'cmap' not in self.tables:
raise TrueTypeFont.CMapNotFound
(base_offset, length) = self.tables['cmap']
fp = self.fp
fp.seek(base_offset)
(version, nsubtables) = struct.unpack('>HH', fp.read(4))
subtables = []
for i in xrange(nsubtables):
subtables.append(struct.unpack('>HHL', fp.read(8)))
char2gid = {}
# Only supports subtable type 0, 2 and 4.
for (_1, _2, st_offset) in subtables:
fp.seek(base_offset+st_offset)
(fmttype, fmtlen, fmtlang) = struct.unpack('>HHH', fp.read(6))
if fmttype == 0:
char2gid.update(enumerate(struct.unpack('>256B', fp.read(256))))
elif fmttype == 2:
subheaderkeys = struct.unpack('>256H', fp.read(512))
firstbytes = [0]*8192
for (i,k) in enumerate(subheaderkeys):
firstbytes[k/8] = i
nhdrs = max(subheaderkeys)/8 + 1
hdrs = []
for i in xrange(nhdrs):
(firstcode,entcount,delta,offset) = struct.unpack('>HHhH', fp.read(8))
hdrs.append((i,firstcode,entcount,delta,fp.tell()-2+offset))
for (i,firstcode,entcount,delta,pos) in hdrs:
if not entcount: continue
first = firstcode + (firstbytes[i] << 8)
fp.seek(pos)
for c in xrange(entcount):
gid = struct.unpack('>H', fp.read(2))
if gid:
gid += delta
char2gid[first+c] = gid
elif fmttype == 4:
(segcount, _1, _2, _3) = struct.unpack('>HHHH', fp.read(8))
segcount /= 2
ecs = struct.unpack('>%dH' % segcount, fp.read(2*segcount))
fp.read(2)
scs = struct.unpack('>%dH' % segcount, fp.read(2*segcount))
idds = struct.unpack('>%dh' % segcount, fp.read(2*segcount))
pos = fp.tell()
idrs = struct.unpack('>%dH' % segcount, fp.read(2*segcount))
for (ec,sc,idd,idr) in zip(ecs, scs, idds, idrs):
if idr:
fp.seek(pos+idr)
for c in xrange(sc, ec+1):
char2gid[c] = (struct.unpack('>H', fp.read(2))[0] + idd) & 0xffff
else:
for c in xrange(sc, ec+1):
char2gid[c] = (c + idd) & 0xffff
else:
assert 0
# create unicode map
unicode_map = FileUnicodeMap()
for (char,gid) in char2gid.iteritems():
unicode_map.add_cid2unichr(gid, char)
return unicode_map
