from fontTools.misc import sstruct
from fontTools.misc.fixedTools import floatToFixedToStr
from fontTools.misc.textTools import safeEval
from . import DefaultTable
from . import grUtils
import struct
Feat_hdr_format = """
>
version: 16.16F
"""
[docs]
class table_F__e_a_t(DefaultTable.DefaultTable):
"""The ``Feat`` table is used exclusively by the Graphite shaping engine
to store features and possible settings specified in GDL. Graphite features
determine what rules are applied to transform a glyph stream.
Not to be confused with ``feat``, or the OpenType Layout tables
``GSUB``/``GPOS``."""
def __init__(self, tag=None):
DefaultTable.DefaultTable.__init__(self, tag)
self.features = {}
[docs]
def decompile(self, data, ttFont):
(_, data) = sstruct.unpack2(Feat_hdr_format, data, self)
self.version = float(floatToFixedToStr(self.version, precisionBits=16))
(numFeats,) = struct.unpack(">H", data[:2])
data = data[8:]
allfeats = []
maxsetting = 0
for i in range(numFeats):
if self.version >= 2.0:
(fid, nums, _, offset, flags, lid) = struct.unpack(
">LHHLHH", data[16 * i : 16 * (i + 1)]
)
offset = int((offset - 12 - 16 * numFeats) / 4)
else:
(fid, nums, offset, flags, lid) = struct.unpack(
">HHLHH", data[12 * i : 12 * (i + 1)]
)
offset = int((offset - 12 - 12 * numFeats) / 4)
allfeats.append((fid, nums, offset, flags, lid))
maxsetting = max(maxsetting, offset + nums)
data = data[16 * numFeats :]
allsettings = []
for i in range(maxsetting):
if len(data) >= 4 * (i + 1):
(val, lid) = struct.unpack(">HH", data[4 * i : 4 * (i + 1)])
allsettings.append((val, lid))
for i, f in enumerate(allfeats):
(fid, nums, offset, flags, lid) = f
fobj = Feature()
fobj.flags = flags
fobj.label = lid
self.features[grUtils.num2tag(fid)] = fobj
fobj.settings = {}
fobj.default = None
fobj.index = i
for i in range(offset, offset + nums):
if i >= len(allsettings):
continue
(vid, vlid) = allsettings[i]
fobj.settings[vid] = vlid
if fobj.default is None:
fobj.default = vid
[docs]
def compile(self, ttFont):
fdat = b""
vdat = b""
offset = 0
for f, v in sorted(self.features.items(), key=lambda x: x[1].index):
fnum = grUtils.tag2num(f)
if self.version >= 2.0:
fdat += struct.pack(
">LHHLHH",
grUtils.tag2num(f),
len(v.settings),
0,
offset * 4 + 12 + 16 * len(self.features),
v.flags,
v.label,
)
elif fnum > 65535: # self healing for alphabetic ids
self.version = 2.0
return self.compile(ttFont)
else:
fdat += struct.pack(
">HHLHH",
grUtils.tag2num(f),
len(v.settings),
offset * 4 + 12 + 12 * len(self.features),
v.flags,
v.label,
)
for s, l in sorted(
v.settings.items(), key=lambda x: (-1, x[1]) if x[0] == v.default else x
):
vdat += struct.pack(">HH", s, l)
offset += len(v.settings)
hdr = sstruct.pack(Feat_hdr_format, self)
return hdr + struct.pack(">HHL", len(self.features), 0, 0) + fdat + vdat
[docs]
def toXML(self, writer, ttFont):
writer.simpletag("version", version=self.version)
writer.newline()
for f, v in sorted(self.features.items(), key=lambda x: x[1].index):
writer.begintag(
"feature",
fid=f,
label=v.label,
flags=v.flags,
default=(v.default if v.default else 0),
)
writer.newline()
for s, l in sorted(v.settings.items()):
writer.simpletag("setting", value=s, label=l)
writer.newline()
writer.endtag("feature")
writer.newline()
[docs]
def fromXML(self, name, attrs, content, ttFont):
if name == "version":
self.version = float(safeEval(attrs["version"]))
elif name == "feature":
fid = attrs["fid"]
fobj = Feature()
fobj.flags = int(safeEval(attrs["flags"]))
fobj.label = int(safeEval(attrs["label"]))
fobj.default = int(safeEval(attrs.get("default", "0")))
fobj.index = len(self.features)
self.features[fid] = fobj
fobj.settings = {}
for element in content:
if not isinstance(element, tuple):
continue
tag, a, c = element
if tag == "setting":
fobj.settings[int(safeEval(a["value"]))] = int(safeEval(a["label"]))
[docs]
class Feature(object):
pass