""" The FontFeatures class is a way of representing the transformations - substitutions and positionings - going on inside a font at a semantically high level. It aims to be independent of and unconstrained by the OpenType representation, with the assumption that these high-level objects can be either "compiled down" into AFDKO feature code or directly written to the GSUB/GPOS tables of a font. FontFeatures aims to marshal data between OTF binary representations, AFDKO feature code, FontDame, and can power other representations such as the FEZ language (see the 'fez' library). A FontFeatures representation of a font will make use of two other top-level concepts: Features and Routines. Routines are collections of rules; they play a similar function to the AFDKO concept of a lookup, but unlike lookups, Routines do not need to be comprised of rules of the same type. You can think of them as functions that are called on a glyph string. Here is an example of constructing a simple feature file using fontFeatures:: ff = FontFeatures() liga_ffi = Substitution( [ ["f"], ["f"], ["i"] ], replacement=[["f_f_i"]] ) liga_ffl = Substitution( [ ["f"], ["f"], ["l"] ], replacement=[["f_f_l"]] ) liga_fi = Substitution( [ ["f"], ["i"] ], replacement=[["fi"]] ) liga_ff = Substitution( [ ["f"], ["f"] ], replacement=[["f_f"]] ) liga_routine = Routine(rules=[liga_ffi, liga_ffl, liga_fi, liga_ff]) ff.addFeature("liga", [liga_routine]) # Export Adobe syntax print(ff.asFea()) font = TTFont("Test.ttf") ff.buildBinaryFeatures(font) font.save("Test-liga.ttf") """ from collections import OrderedDict from fontTools.feaLib.ast import ValueRecord as feaLibValueRecord from fontTools.feaLib.variableScalar import VariableScalar from itertools import chain from copy import copy class FontFeatures: """An object representing the layout rules in a font. The initializer has no parameters.""" def __init__(self): self.namedClasses = ( {} ) #: A mapping of named classes to a list of glyph names which make up the class. self.routines = [] #: All of the layout routines used in this font. self.features = ( OrderedDict() ) #: An ordered dictionary mapping feature tags to a list of routine references. self.anchors = ( {} ) #: A dictionary mapping glyph names to a dictionary of anchor names / positions. self.symbols = {} self.glyphclasses = {} #: A dictionary mapping glyph names to their categories. self.scratch = {} #: Space for items to communicate context to each other. self.doneUsageMarking = False def __add__(self, other): """Combine two FontFeatures objects together.""" combined = FontFeatures() for k in [ "namedClasses", "routines", "features", "anchors", "symbols", "glyphclasses", ]: if isinstance(getattr(combined, k), dict): getattr(combined, k).update(getattr(self, k)) getattr(combined, k).update(getattr(other, k)) else: setattr(combined, k, getattr(self, k) + getattr(other, k)) return combined def gensym(self, category): """Generate a new unique symbol (used for labeling unlabeled data). Args: category (str): The category for this symbol Returns: a string representing a unique label.""" if category not in self.symbols: self.symbols[category] = 0 self.symbols[category] += 1 return f"{category}{self.symbols[category]}" def routineNamed(self, name): """Finds a routine with the given name. Args: name (str): The name to find Returns: a :py:class:`Routine` object if the named routine was found in the features object. Raises a ``ValueError`` if not.""" for r in self.routines: if r.name == name: return r raise ValueError("Can't find routine '%s'" % name) def referenceRoutine(self, r, do_usecount=True): """Store a routine and return a reference to it. Args: r: A :py:class:`Routine` object. """ assert isinstance(r, Routine) if r not in self.routines: self.routines.append(r) r.parent = self if do_usecount: r.usecount = r.usecount + 1 return RoutineReference(routine=r) def getNamedClassFor(self, glyphs, name): """Find and optionally stores a named class of glyphs Args: glyphs: A sequence of glyph names. name: A name for this glyph class if it does not exist. Returns: The name of a glyph class. If the exact same set of glyphs was already stored as a glyph class, then the name of that class will be returned. If not, then the class will be stored and the name provided as the ``name`` argument will be returned. """ for k, v in self.namedClasses.items(): if sorted(glyphs) == sorted(v): return k self.namedClasses[name] = glyphs return name def addFeature(self, name, rs): """Add Routines to a named feature. Args: name: The feature name. rs: A sequence of :py:class:`Routine` or :py:class:`RoutineReference` objects. """ if name not in self.features: self.features[name] = [] for r in rs: r.parent = self if isinstance(r, Routine): r = self.referenceRoutine(r) self.features[name].append(r) def allRules(self, ruletype=None): """Return all rules in the font, optionally filtered by type Args: ruletype: A class (``Positioning``, ``Substitution`` etc) to filter the results. Returns: Routines stored in the preamble and within features. """ rules = [] for r in self.routines: rules.extend(r.rules) if ruletype: rules = filter(lambda x: isinstance(x, ruletype), rules) return rules def markRoutineUseInChains(self): """Annotate routines which are used in chaining rules. Generally used when converting the fontFeatures object to another format; allows routines to know where they are being used by annotating them with the ``.usedin`` property for optimization purposes. """ if self.doneUsageMarking: return for r in self.routines: r.usedin = set() for chain_rule in self.allRules(Chaining): for routinelist in chain_rule.lookups: if not routinelist: continue for routine in routinelist: # Using a set here so it is safe to call more than once if isinstance(routine, RoutineReference): routine.resolve(self) routine.routine.usedin.add(chain_rule) else: routine.usedin.add(chain_rule) self.doneUsageMarking = True def hoist_languages(self): """Sort routines into scripts and languages and resolve wildcards.""" scripts = OrderedDict() count = 0 def add_language(p): nonlocal scripts nonlocal count script, lang = p if script not in scripts: scripts[script] = [] if lang == "*": return if lang not in scripts[script]: count = count + 1 scripts[script].append(lang) for k in self.routines: if k.languages: for lang in k.languages: add_language(lang) else: for r in k.rules: for lang in r.languages or []: add_language(lang) # if count > 0 and not "DFLT" in scripts: # scripts["DFLT"] = [] # scripts.move_to_end("DFLT", last=False) # if count > 0 and not "dflt" in scripts["DFLT"]: # scripts["DFLT"].insert(0, "dflt") self.scripts_and_languages = scripts def hasScriptSupport(self, script): """Check if the features object has support for a particular script. Args: script (str): A four-character OpenType script code. Returns: boolean """ self.hoist_languages() return script in self.scripts_and_languages def resolveAllRoutines(self): """Resolve reference use in chains. Checks that all routines referenced in chain rules can actually be found within the object, and adds pointers to match named routine references with the relevant :py:class:`Routine` object. """ for routine in self.routines: for r in routine.rules: if not isinstance(r, Chaining): continue for lookuplistIx in range(len(r.lookups)): r.lookups[lookuplistIx] = self.ensureLookupsAreReferences( r.lookups[lookuplistIx] ) def ensureLookupsAreReferences(self, lookuplist): """Ensures that all references are lookups. Naughty people might put :py:class:`Routine` objects directly into :py:class:`Chain` lookups. This tidies them up.""" rv = [] if not lookuplist: return None for r in lookuplist: if isinstance(r, RoutineReference): r.resolve(self) else: r = self.referenceRoutine(r) assert r.routine in self.routines rv.append(r) return rv def setGlyphClassesFromFont(self, font): """Loads glyph classes from the font.""" for g in font.exported_glyphs(): if hasattr(font, "glyphs"): self.glyphclasses[g] = font.glyphs[g].category else: self.glyphclasses[g] = font[g].category def partitionRoutine(self, routine, factor): """Splits a routine based on a predicate. This method applies a function to each rule in the routine and creates distinct routines, each containing rules with the same return value from the function. This is useful, for example, when exporting to OpenType, to ensure that all rules in a routine must have the same type, same flags, etc. Args: routine: A :py:class:`Routine` object. factor: A function applied to each of the :py:class:`Rule` objects. Returns: A list of :py:class:`Routine` objects. Additionally, modifies the ``.routines`` list of the FontFeatures object.""" if not routine.rules: return self.doneUsageMarking = False self.markRoutineUseInChains() split_routines = {} # The first rule stays in the original split_routines[factor(routine.rules[0])] = (routine, [routine.rules[0]]) for rule in routine.rules[1:]: thisfactor = factor(rule) if thisfactor not in split_routines: rulelist = [] newroutine = copy(routine) newroutine.rules = rulelist split_routines[thisfactor] = (newroutine, rulelist) split_routines[thisfactor][1].append(rule) # Alter the first rule's routine's rulelist (we couldn't alter it on # the fly because we were iterating over it). routine_with_first_rule, rulelist = split_routines[factor(routine.rules[0])] routine_with_first_rule.rules = rulelist allroutines = [x[0] for x in split_routines.values()] return self.replaceRoutineWithSplitList(routine, allroutines) def replaceRoutineWithSplitList(self, routine, allroutines): self.markRoutineUseInChains() index = self.routines.index(routine) usedin = routine.usedin self.routines[index : index + 1] = allroutines for user in usedin: for lookuplist in user.lookups: if lookuplist is None: continue i = 0 while i < len(lookuplist): lookup = lookuplist[i] if lookup == routine or ( isinstance(lookup, RoutineReference) and lookup.routine == routine ): lookuplist[i : i + 1] = [ RoutineReference(routine=r) for r in allroutines ] i = i + 1 # Same trick for features for lookuplist in self.features.values(): if lookuplist is None: continue i = 0 while i < len(lookuplist): lookup = lookuplist[i] if lookup == routine or ( isinstance(lookup, RoutineReference) and lookup.routine == routine ): lookuplist[i : i + 1] = [ RoutineReference(routine=r) for r in allroutines ] i = i + 1 return allroutines from .feaLib.FontFeatures import asFea, asFeaAST from .xmlLib.FontFeatures import toXML, fromXML from .ttLib.FontFeatures import buildBinaryFeatures class Routine: """Represent a Routine (similar to OT Lookup). A routine is a set of rules, sometimes but not always with an explicit name. It can apply to a set of language/script pairs. """ def __init__( self, name="", rules=None, address=None, inlined=False, languages=None, parent=None, flags=0, markFilteringSet=None, markAttachmentSet=None, ): self.name = name self.usecount = 0 self.usedin = set() if rules: self.rules = rules else: self.rules = [] self.address = address self.comments = [] self.inlined = inlined self.languages = languages or [] self.parent = parent self.flags = flags self.markFilteringSet = markFilteringSet self.markAttachmentSet = markAttachmentSet def addRule(self, rule): """Adds a rule to a Routine. Args: rule: A ``Substitution``, ``Positioning``, etc. object. """ assert isinstance(rule, Rule) self.rules.append(rule) def addComment(self, comment): """Adds a comment to a Routine. Comments are emitted when the Routine is converted to text formats such as AFDKO. Args: comment: A string comment. """ self.comments.append(comment) @property def involved_glyphs(self): """Returns the names of all of the glyphs involved in this Routine.""" return set().union(*(r.involved_glyphs for r in self.rules)) @property def stage(self): """Returns which shaping stage this routine is used in. Returns: ``sub`` for substitution stage, ``pos`` for positioning stage.""" for r in self.rules: if isinstance(r, Substitution): return "sub" if isinstance(r, Positioning): return "pos" if isinstance(r, Attachment): return "pos" if isinstance(r, Chaining): return r.stage @property def dependencies(self): """Returns a list of :py:class:`Routine` objects called as lookups in this Routine.""" deps = [] for r in self.rules: deps.extend(r.dependencies) return deps from .feaLib.Routine import asFea, asFeaAST, feaPreamble from .shaperLib.Routine import apply_to_buffer from .xmlLib.Routine import toXML, fromXML from .ttLib.Routine import toOTLookup class ExtensionRoutine(Routine): """OpenType-specific concept: A routine which contains other routines.""" def __init__(self, **kwargs): if "routines" in kwargs: self.routines = kwargs["routines"] del kwargs["routines"] super().__init__(**kwargs) def apply_to_buffer(self, buf, stage=None, feature=None): """Applies shaping rules from this routine to a buffer. Args: buf: A :py:class:`fontFeatures.shaperLib.Buffer` object. stage (str): Shaping stage - ``sub`` or ``pos``. feature (str): The feature being processed. (For debugging.) Modifies the ``buf`` object. """ for r in self.routines: r.apply_to_buffer(buf, stage, feature) def asFeaAST(self): """Returns this extension routine as ``fontTools.feaLib.ast`` objects.""" import fontTools.feaLib.ast as feaast f = feaast.Block() for r in self.routines: f.statements.append(r.asFeaAST()) return f @property def stage(self): """Returns which shaping stage this routine is used in. Returns: ``sub`` for substitution stage, ``pos`` for positioning stage.""" return self.routines[0].stage @property def rules(self): """All rules under this extension. Returns: A flattened list of :py:class:`Rule` objects.""" return list(chain(*[routine.rules for routine in self.routines])) @rules.setter def rules(self, foo): """Does nothing. Don't set rules here.""" pass class RoutineReference: """A reference to a Routine object, used in a lookup. Routines can be referenced either by name (for example, when loaded from a textual representation), in which case they will be resolved at a later time, or by providing a pointer to the :py:class:`Routine` object.""" def __init__(self, name=None, routine=None): self.languages = [] self.routine = routine if self.routine: self.name = routine.name if name: self.name = name def resolve(self, ff): """Resolves the reference in the context of a :py:class:`FontFeatures` object. Raises a ``ValueError`` if a named routine cannot be found. """ if not self.routine: self.routine = ff.routineNamed(self.name) if not self.routine: raise ValueError("Could not resolve routine") if not self.name: self.name = self.routine.name @property def stage(self): """Returns which shaping stage this routine is used in. Returns: ``sub`` for substitution stage, ``pos`` for positioning stage.""" if not self.routine: raise ValueError("Routine reference not resolved") return self.routine.stage from .xmlLib.RoutineReference import fromXML, toXML from .feaLib.RoutineReference import asFeaAST, feaPreamble def asFea(self): """Returns this Rule as a string of AFDKO feature text.""" return self.asFeaAST().asFea() class Rule: """A base class for all rules.""" def asFea(self): """Returns this Rule as a string of AFDKO feature text.""" return self.asFeaAST().asFea() def feaPreamble(self, ff): """Computes any text that needs to go in the feature file header.""" return [] from .shaperLib.Rule import would_apply_at_position, pre_post_context_matches from .xmlLib.Rule import fromXML, toXML, _makeglyphslots, _slotArray @property def has_context(self): """Does this rule have any pre- or post-context defined?""" return len(self.precontext) or len(self.postcontext) @property def dependencies(self): """Returns a list of :py:class:`Routine` objects called as lookups in this Routine.""" return [] class Substitution(Rule): """Represents a Substitution rule. A substitution represents any kind of exchange of one set of glyphs for another: single substitutions, multiple substitutions and ligatures are all substitutions. Optionally, substitutions may be followed by precontext and postcontext. Args: input_: A list of lists. The outer list represents the positions in the glyph stream to substitute, with the inner list representing the glyph names at each position. replacement: A list of glyph names. precontext: A list of list of glyphs which must appear before the input sequence. postcontext: A list of list of glyphs which must appear before the input sequence. lookups: A list of list of lookups to be applied to the glyph sequence. The outer list represents the positions in the input sequence, with the inner list containing Routines to apply. reverse: Boolean representing if the substitutions should take place from the end of the string. force_alt: Force this substitution to be interpreted as an alternate substitution. Examples:: lig = Substitution( [ ["f"], ["i"] ], ["f_i"] ) # sub f i by f_i; contextual = Substitution( [ ["dotbelow"] ], [ ["dotbelow.post"] ], precontext = [["ra-myanmar", "ra-myanmar.bt1", "ra-myanmar.bt2"]] ) # sub [ra-myanmar ra-myanmar.bt1 ra-myanmar.bt2] dotbelow-myanmar' # by dotbelow-myanmar.post; """ def __init__( self, input_, replacement, precontext=None, postcontext=None, address=None, languages=None, lookups=None, reverse=False, flags=0, force_alt=False, ): self.precontext = precontext or [] self.postcontext = postcontext or [] self.input = input_ self.replacement = replacement self.address = address self.lookups = lookups or [] self.languages = languages self.flags = flags self.reverse = reverse self.stage = "sub" self.force_alt = force_alt @property def involved_glyphs(self): """Returns a set of all glyphs involved in this rule.""" i = set(chain.from_iterable(self.input)) o = set(chain.from_iterable(self.replacement)) b = set(chain.from_iterable(self.precontext)) a = set(chain.from_iterable(self.postcontext)) return i | o | b | a from .feaLib.Substitution import asFeaAST from .shaperLib.Substitution import shaper_inputs, _do_apply from .xmlLib.Substitution import _toXML, fromXML from .ttLib.Substitution import lookup_type class Chaining(Rule): """Represents a Chain rule. A Chain rule represents the operation of calling another Routine when a particular input context is met. Args: input_: A list of lists. The outer list represents the positions in the glyph stream to substitute, with the inner list representing the glyph names at each position. precontext: A list of list of glyphs which must appear before the input sequence. postcontext: A list of list of glyphs which must appear before the input sequence. lookups: A list of list of lookups to be applied to the glyph sequence. The outer list represents the positions in the input sequence, with the inner list containing Routines to apply. Example:: sub_Qu = Routine(rules=[ Substitute([["Q"]], [["Q.beforeu"]]) ]) chain = Chain( [["Q"]], postcontext = [ ["u", "v", "u.sc", "v.sc"] ], lookups = [ [sub_Qu] ] ) # sub Q' lookup sub_Qu [u v u.sc v.sc]; """ def __init__( self, input_, precontext=None, postcontext=None, address=None, languages=None, lookups=None, flags=0, ): self.precontext = precontext or [] self.postcontext = postcontext or [] self.input = input_ self.address = address self.lookups = lookups or [] self.languages = languages self.flags = flags @property def stage(self): """Returns which shaping stage this routine is used in. Returns: ``sub`` for substitution stage, ``pos`` for positioning stage.""" for lookuplist in self.lookups: if not lookuplist: continue for aLookup in lookuplist: if not aLookup: continue return aLookup.stage @property def involved_glyphs(self): """Returns a set of all glyphs involved in this rule.""" i = set(chain.from_iterable(self.input)) b = set(chain.from_iterable(self.precontext)) a = set(chain.from_iterable(self.postcontext)) return i | b | a @property def dependencies(self): """Returns a list of :py:class:`Routine` objects called as lookups in this Routine.""" deps = [] for lookuplist in self.lookups: for aLookup in lookuplist or []: if isinstance(aLookup, RoutineReference): deps.append(aLookup.routine) else: deps.append(aLookup) return deps from .feaLib.Chaining import asFeaAST, feaPreamble from .shaperLib.Chaining import shaper_inputs, _do_apply from .xmlLib.Chaining import _toXML, fromXML from .ttLib.Chaining import lookup_type class ValueRecord(feaLibValueRecord): """A value record for representing positional changes in advance and placement. See :py:class:`fontTools.feaLib.ValueRecord`, from which this inherits. """ from .ttLib.ValueRecord import toOTValueRecord @property def is_variable(self): """Returns true if any of the elements of the value record are a :py:class:`fontTools.feaLib.VariableScalar`.""" return any( isinstance(x, VariableScalar) for x in [ self.xPlacement, self.yPlacement, self.xAdvance, self.yAdvance, ] ) class Positioning(Rule): """Represents a Positioning rule. Args: input_: A list of lists. The outer list represents the positions in the glyph stream to position, with the inner list representing the glyph names at each glyph stream position. valuerecords: A list of ``ValueRecord`` objects to be applied at each glyph stream position. precontext: A list of list of glyphs which must appear before the input sequence. postcontext: A list of list of glyphs which must appear before the input sequence. Example:: open_up_behs = Positioning( [ ["BEi1", "BEi2"], ["sda", "sdb", "dda", "ddb"] ], [ ValueRecord(xAdvance=200), ValueRecord(xPlacement=50), ] postcontext = [ medis_finas ] ) # pos [BEi1 BEi2]' <0 0 200 0> [sda sdb dda ddb]' <0 50 0 0> @medis_finas; """ def __init__( self, glyphs, valuerecords, precontext=None, postcontext=None, address=None, languages=None, flags=0, ): self.precontext = precontext or [] self.postcontext = postcontext or [] assert len(glyphs) == len(valuerecords) self.glyphs = glyphs self.valuerecords = valuerecords self.address = address self.languages = languages self.flags = flags self.stage = "pos" @property def involved_glyphs(self): """Returns a set of all glyphs involved in this rule.""" i = set(chain.from_iterable(self.glyphs)) b = set(chain.from_iterable(self.precontext)) a = set(chain.from_iterable(self.postcontext)) return i | b | a from .feaLib.Positioning import asFeaAST from .shaperLib.Positioning import shaper_inputs, _do_apply from .xmlLib.Positioning import _toXML, fromXML from .ttLib.Positioning import lookup_type class Attachment(Rule): """Represents an Attachment rule. Args: base_name: Name of the base class. mark_name: Name of the mark class. bases: Dictionary. They keys are names of glyphs to act as bases to the attachment (this may be categorized as mark glyphs if the attachment is a mark-to-mark operation); the associated values are a two-element tuple with the coordinates of the anchor. marks: Dictionary. They keys are names of glyphs to act as marks; the associated values are a two-element tuple with the coordinates of the anchor. force_markmark: boolean. If true, force this to be interpreted as a mark-to-mark operation Whether this is a mark-to-base or mark-to-mark operation will be determined by the glyph category of the glyphs involved in the `bases` dictionary and the value of the `force_markmark` argument. Examples:: ff.anchors = { "a": { "top": (250, 603) }, "acutecomb": { "_top": (56, 0) } } top_bases = {} top_marks = {} for glyphname, anchors in ff.anchors.items(): for anchorname, position in anchors.items(): if anchorname == "top": top_bases[glyphname] = position if anchorname == "_top": top_marks[glyphname] = position # top_bases = { "a": (260,603) } # top_marks = { "acutecomb": (56,0) } tops = Attachment("top", "_top", top_bases, top_marks) """ def __init__( self, base_name, mark_name, bases=None, marks=None, fullname=None, flags=0, address=None, font=None, languages=None, force_markmark=False, ): self.base_name = base_name self.mark_name = mark_name self.fullname = fullname or (self.base_name + "_" + self.mark_name) self.bases = bases or {} self.marks = marks or {} self.flags = flags self.address = address self.font = font self.stage = "pos" self.languages = languages or [] self.force_markmark = force_markmark @property def is_cursive(self): """Returns true if this is a cursive attachment rule.""" return self.base_name == "cursive_entry" or self.base_name == "entry" # XXX from .feaLib.Attachment import asFeaAST, feaPreamble from .shaperLib.Attachment import shaper_inputs, _do_apply, would_apply_at_position from .xmlLib.Attachment import _toXML, fromXML from .ttLib.Attachment import lookup_type @property def involved_glyphs(self): """Returns a set of all glyphs involved in this rule.""" b = set(self.bases.keys()) m = set(self.marks.keys()) return b | m