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"""A Python Unicode Shaping Engine."""
from fontFeatures import FontFeatures
from .BaseShaper import BaseShaper
from .ArabicShaper import ArabicShaper
from .IndicShaper import IndicShaper
from .MyanmarShaper import MyanmarShaper
from .HangulShaper import HangulShaper
from .KhmerShaper import KhmerShaper
from .USEShaper import USEShaper
import logging
import re
class Shaper:
"""Initialize a shaping engine.
Args:
ff: A :py:class:`fontFeatures.FontFeatures` object.
font: A ``Babelfont`` font object.
message_function: A function called with a message and buffer object.
"""
def __init__(self, ff, font, message_function=None):
assert isinstance(ff, FontFeatures)
self.fontfeatures = ff
self.babelfont = font
if message_function:
self.msg = message_function
else:
self.msg = self.default_message_function
def execute(self, buf, features=[]):
"""Run the shaper on a given buffer.
Args:
buf: :py:class:`fontFeatures.shaperLib.buffer.Buffer` object.
features: either a list of feature tags or a feature string ("+foox,-barx")
"""
# Choose complex shaper
self.complexshaper = self.categorize(buf)(self, self.babelfont, buf, features)
self.msg("Using %s" % type(self.complexshaper).__name__)
self.stages = [[]]
if isinstance(features, str):
self.user_features = self._parse_user_feature_string(features)
else:
self.user_features = features
self.collect_features(buf)
self.complexshaper.shape()
buf.clear_mask()
return buf
def default_message_function(self, msg, buffer=None, serialize_options=None):
"""A logger function to be used if one is not provided in the constructor.
By default, debugging and informational log messages are reported to the
``fontFeatures.shaperLib`` facility."""
ser = ""
if buffer:
ser = buffer.serialize(additional=serialize_options)
msg = msg + " : " + ser
logging.getLogger("fontFeatures.shaperLib").info(msg)
def _parse_user_feature_string(self, features):
features = features.split(",")
outfeat = []
for f in features:
f = f.rstrip()
m = re.match(r"^([+\-]?)(\w+)", f)
if m:
outfeat.append({"tag": m[2], "value": m[1] != "-"})
continue
m = re.match(r"^(\w+)=([10])", f)
if m:
outfeat.append({"tag": m[1], "value": m[2] == "1"})
else:
outfeat.append({"tag": f, "value": True})
return outfeat
def add_pause(self, thing=None):
"""Add a pause in the shaping stage. Used internally."""
if thing:
self.stages.append(thing)
self.stages.append([])
def add_features(self, *tags):
"""Adds feature tags to the current shaping stage."""
for t in tags:
if any([isinstance(x, list) and t in x for x in self.stages]):
continue
self.stages[-1].append(t)
def disable_feature(self, tag):
"""Removes a feature from processing."""
for s in self.stages:
if isinstance(s, list) and tag in s:
s.remove(tag)
def collect_features(self, buf):
"""Determine the features, and their order, to process the buffer."""
self.add_features("rvrn")
self.add_pause()
if buf.direction == "LTR":
self.add_features("ltra", "ltrm")
elif buf.direction == "RTL":
self.add_features("rtla", "rtlm")
self.add_features("frac", "numr", "dnom", "rand")
# trak?
self.complexshaper.collect_features(self)
# common features
self.add_features("abvm", "blwm", "ccmp", "locl", "mark", "mkmk", "rlig")
if buf.direction == "LTR" or buf.direction == "RTL":
self.add_features("calt", "clig", "curs", "dist", "kern", "liga", "rclt")
else:
self.add_features("vert")
for uf in self.user_features:
if not uf["value"]: # Turn it off if it's already on
self.disable_feature(uf["tag"])
else:
self.add_features(uf["tag"])
if hasattr(self.complexshaper, "override_features"):
self.complexshaper.override_features(self)
def categorize(self, buf):
"""Returns the appropriate complex shaper class to shape this buffer."""
if buf.script == "Arabic":
return ArabicShaper
connected_scripts = {
"Mongolian": "mong",
"Syriac": "syrc",
"Nko": "nko ",
"Phags_Pa": "phag",
"Mandaic": "mand",
"Manichaean": "mand",
"Psalter_Pahlavi": "phlp",
"Adlam": "adlm",
"Hanifi_Rohingya": "rohg",
"Sogdian": "sogd",
}
if buf.script in connected_scripts:
if self.fontfeatures.hasScriptSupport(connected_scripts[buf.script]):
return ArabicShaper
else:
return BaseShaper
# if buf.script in ["Thai", "Lao"]:
# return ThaiShaper
if buf.script == "Hangul":
return HangulShaper
# if buf.script == "Hebrew":
# return HebrewShaper
if buf.script in [
"Bengali",
"Devanagari",
"Gujarati",
"Gurmukhi",
"Kannada",
"Malayalam",
"Oriya",
"Tamil",
"Telugu",
"Sinhala",
]:
indic23map = {
"Bengali": "bng",
"Devanagari": "dev",
"Gujarati": "gjr",
"Gurmukhi": "gur",
"Kannada": "knd",
"Malayalam": "mlm",
"Oriya": "ory",
"Tamil": "tml",
"Telugu": "tel",
}
# Sinhala is different
if buf.script in indic23map and self.fontfeatures.hasScriptSupport(
indic23map[buf.script] + "3"
):
return USEShaper
else:
return IndicShaper
if buf.script == "Khmer":
return KhmerShaper
if buf.script == "Myanmar":
if self.fontfeatures.hasScriptSupport("mymr"):
return BaseShaper
else:
return MyanmarShaper
# if buf.script = "Qaag": return MyanmarZawgyiShaper
if buf.script in [
"Tibetan",
"Buhid",
"Hanunoo",
"Tagalog",
"Tagbanwa",
"Limbu",
"Tai_Le",
"Buginese",
"Kharoshthi",
"Syloti_Nagri",
"Tifinagh",
"Balinese",
"Cham",
"Kayah_Li",
"Lepcha",
"Rejang",
"Saurashtra",
"Sundanese",
"Egyptian_Hieroglyphs",
"Javanese",
"Kaithi",
"Meetei_Mayek",
"Tai_Tham",
"Tai_Viet",
"Batak",
"Brahmi",
"Chakma",
"Sharada",
"Takri",
"Duployan",
"Grantha",
"Khojki",
"Khudawadi",
"Mahajani",
"Modi",
"Pahawh_Hmong",
"Siddham",
"Tirhuta",
"Ahom",
"Bhaiksuki",
"Marchen",
"Newa",
"Masaram_Gondi",
"Soyombo",
"Zanabazar_Square",
"Dogra",
"Gunjala_Gondi",
"Makasar",
"Nandinagari",
]:
return USEShaper
return BaseShaper
def _script_direction(script):
if script in [
"Arabic",
"Hebrew",
"Syriac",
"Thaana",
"Cypriot",
"Kharoshthi",
"Phoenician",
"Nko",
"Lydian",
"Avestan",
"Imperial_Aramaic",
"Inscriptional_Parthian",
"Inscriptional_Pahlavi",
"Old_South_Arabian",
"Old_Turkic",
"Samaritan",
"Mandaic",
"Meroitic_Cursive",
"Meroitic_Hieroglyphs",
"Manichaean",
"Mende_Kikakui",
"Nabataean",
"Old_North_Arabian",
"Palmyrene",
"Psalter_Pahlavi",
"Hatran",
"Adlam",
"Hanifi_Rohingya",
"Old_Sogdian",
"Sogdian",
"Elymaic",
"Chorasmian",
"Yezidi",
]:
return "RTL"
if script in ["Old_Hungarian", "Old_Italic", "Runic"]:
return "invalid"
return "LTR"
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