248 lines
7.6 KiB
Python
248 lines
7.6 KiB
Python
from __future__ import print_function, division, absolute_import
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from fontTools.misc.psCharStrings import CFF2Subr
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from fontTools.pens.t2CharStringPen import T2CharStringPen, t2c_round
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from fontTools.cffLib.specializer import (commandsToProgram,
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specializeCommands)
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from fontTools.cffLib import maxStackLimit
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from fontTools.varLib.models import allEqual
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class MergeTypeError(TypeError):
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def __init__(self, point_type, pt_index, m_index, default_type, glyphName):
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self.error_msg = [
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"In glyph '{gname}' "
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"'{point_type}' at point index {pt_index} in master "
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"index {m_index} differs from the default font point "
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"type '{default_type}'"
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"".format(gname=glyphName,
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point_type=point_type, pt_index=pt_index,
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m_index=m_index, default_type=default_type)
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][0]
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super(MergeTypeError, self).__init__(self.error_msg)
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def makeRoundNumberFunc(tolerance):
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if tolerance < 0:
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raise ValueError("Rounding tolerance must be positive")
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def roundNumber(val):
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return t2c_round(val, tolerance)
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return roundNumber
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class CFF2CharStringMergePen(T2CharStringPen):
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"""Pen to merge Type 2 CharStrings.
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"""
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def __init__(self, default_commands,
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glyphName, num_masters, master_idx, roundTolerance=0.5):
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super(
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CFF2CharStringMergePen,
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self).__init__(width=None,
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glyphSet=None, CFF2=True,
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roundTolerance=roundTolerance)
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self.pt_index = 0
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self._commands = default_commands
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self.m_index = master_idx
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self.num_masters = num_masters
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self.prev_move_idx = 0
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self.glyphName = glyphName
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self.roundNumber = makeRoundNumberFunc(roundTolerance)
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def _p(self, pt):
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""" Unlike T2CharstringPen, this class stores absolute values.
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This is to allow the logic in check_and_fix_closepath() to work,
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where the current or previous absolute point has to be compared to
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the path start-point.
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"""
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self._p0 = pt
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return list(self._p0)
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def add_point(self, point_type, pt_coords):
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if self.m_index == 0:
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self._commands.append([point_type, [pt_coords]])
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else:
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cmd = self._commands[self.pt_index]
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if cmd[0] != point_type:
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# Fix some issues that show up in some
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# CFF workflows, even when fonts are
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# topologically merge compatible.
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success, pt_coords = self.check_and_fix_flat_curve(
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cmd, point_type, pt_coords)
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if not success:
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success = self.check_and_fix_closepath(
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cmd, point_type, pt_coords)
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if success:
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# We may have incremented self.pt_index
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cmd = self._commands[self.pt_index]
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if cmd[0] != point_type:
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success = False
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if not success:
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raise MergeTypeError(point_type,
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self.pt_index, len(cmd[1]),
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cmd[0], self.glyphName)
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cmd[1].append(pt_coords)
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self.pt_index += 1
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def _moveTo(self, pt):
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pt_coords = self._p(pt)
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self.add_point('rmoveto', pt_coords)
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# I set prev_move_idx here because add_point()
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# can change self.pt_index.
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self.prev_move_idx = self.pt_index - 1
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def _lineTo(self, pt):
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pt_coords = self._p(pt)
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self.add_point('rlineto', pt_coords)
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def _curveToOne(self, pt1, pt2, pt3):
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_p = self._p
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pt_coords = _p(pt1)+_p(pt2)+_p(pt3)
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self.add_point('rrcurveto', pt_coords)
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def _closePath(self):
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pass
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def _endPath(self):
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pass
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def restart(self, region_idx):
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self.pt_index = 0
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self.m_index = region_idx
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self._p0 = (0, 0)
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def getCommands(self):
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return self._commands
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def reorder_blend_args(self, commands):
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"""
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We first re-order the master coordinate values.
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For a moveto to lineto, the args are now arranged as:
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[ [master_0 x,y], [master_1 x,y], [master_2 x,y] ]
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We re-arrange this to
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[ [master_0 x, master_1 x, master_2 x],
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[master_0 y, master_1 y, master_2 y]
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]
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We also make the value relative.
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If the master values are all the same, we collapse the list to
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as single value instead of a list.
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"""
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for cmd in commands:
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# arg[i] is the set of arguments for this operator from master i.
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args = cmd[1]
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m_args = zip(*args)
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# m_args[n] is now all num_master args for the i'th argument
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# for this operation.
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cmd[1] = m_args
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# Now convert from absolute to relative
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x0 = [0]*self.num_masters
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y0 = [0]*self.num_masters
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for cmd in self._commands:
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is_x = True
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coords = cmd[1]
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rel_coords = []
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for coord in coords:
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prev_coord = x0 if is_x else y0
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rel_coord = [pt[0] - pt[1] for pt in zip(coord, prev_coord)]
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if allEqual(rel_coord):
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rel_coord = rel_coord[0]
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rel_coords.append(rel_coord)
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if is_x:
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x0 = coord
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else:
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y0 = coord
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is_x = not is_x
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cmd[1] = rel_coords
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return commands
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@staticmethod
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def mergeCommandsToProgram(commands, var_model, round_func):
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"""
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Takes a commands list as returned by programToCommands() and
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converts it back to a T2CharString or CFF2Charstring program list. I
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need to use this rather than specialize.commandsToProgram, as the
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commands produced by CFF2CharStringMergePen initially contains a
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list of coordinate values, one for each master, wherever a single
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coordinate value is expected by the regular logic. The problem with
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doing using the specialize.py functions is that a commands list is
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expected to be a op name with its associated argument list. For the
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commands list here, some of the arguments may need to be converted
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to a new argument list and opcode.
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This version will convert each list of master arguments to a blend
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op and its arguments, and will also combine successive blend ops up
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to the stack limit.
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"""
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program = []
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for op, args in commands:
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num_args = len(args)
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# some of the args may be blend lists, and some may be
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# single coordinate values.
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i = 0
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stack_use = 0
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while i < num_args:
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arg = args[i]
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if not isinstance(arg, list):
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program.append(arg)
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i += 1
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stack_use += 1
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else:
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prev_stack_use = stack_use
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""" The arg is a tuple of blend values.
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These are each (master 0,master 1..master n)
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Combine as many successive tuples as we can,
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up to the max stack limit.
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"""
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num_masters = len(arg)
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blendlist = [arg]
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i += 1
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stack_use += 1 + num_masters # 1 for the num_blends arg
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while (i < num_args) and isinstance(args[i], list):
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blendlist.append(args[i])
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i += 1
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stack_use += num_masters
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if stack_use + num_masters > maxStackLimit:
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# if we are here, max stack is is the CFF2 max stack.
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break
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num_blends = len(blendlist)
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# append the 'num_blends' default font values
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for arg in blendlist:
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if round_func:
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arg[0] = round_func(arg[0])
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program.append(arg[0])
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for arg in blendlist:
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# for each coordinate tuple, append the region deltas
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if len(arg) != 3:
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print(arg)
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import pdb
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pdb.set_trace()
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deltas = var_model.getDeltas(arg)
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if round_func:
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deltas = [round_func(delta) for delta in deltas]
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# First item in 'deltas' is the default master value;
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# for CFF2 data, that has already been written.
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program.extend(deltas[1:])
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program.append(num_blends)
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program.append('blend')
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stack_use = prev_stack_use + num_blends
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if op:
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program.append(op)
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return program
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def getCharString(self, private=None, globalSubrs=None,
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var_model=None, optimize=True):
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commands = self._commands
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commands = self.reorder_blend_args(commands)
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if optimize:
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commands = specializeCommands(commands, generalizeFirst=False,
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maxstack=maxStackLimit)
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program = self.mergeCommandsToProgram(commands, var_model=var_model,
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round_func=self.roundNumber)
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charString = CFF2Subr(program=program, private=private,
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globalSubrs=globalSubrs)
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return charString
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