t2CharStringPen.py 2.9 KB

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  1. # Copyright (c) 2009 Type Supply LLC
  2. # Author: Tal Leming
  3. from __future__ import annotations
  4. from typing import Any, Dict, List, Tuple
  5. from fontTools.cffLib.specializer import commandsToProgram, specializeCommands
  6. from fontTools.misc.psCharStrings import T2CharString
  7. from fontTools.misc.roundTools import otRound, roundFunc
  8. from fontTools.pens.basePen import BasePen
  9. class T2CharStringPen(BasePen):
  10. """Pen to draw Type 2 CharStrings.
  11. The 'roundTolerance' argument controls the rounding of point coordinates.
  12. It is defined as the maximum absolute difference between the original
  13. float and the rounded integer value.
  14. The default tolerance of 0.5 means that all floats are rounded to integer;
  15. a value of 0 disables rounding; values in between will only round floats
  16. which are close to their integral part within the tolerated range.
  17. """
  18. def __init__(
  19. self,
  20. width: float | None,
  21. glyphSet: Dict[str, Any] | None,
  22. roundTolerance: float = 0.5,
  23. CFF2: bool = False,
  24. ) -> None:
  25. super(T2CharStringPen, self).__init__(glyphSet)
  26. self.round = roundFunc(roundTolerance)
  27. self._CFF2 = CFF2
  28. self._width = width
  29. self._commands: List[Tuple[str | bytes, List[float]]] = []
  30. self._p0 = (0, 0)
  31. def _p(self, pt: Tuple[float, float]) -> List[float]:
  32. p0 = self._p0
  33. pt = self._p0 = (self.round(pt[0]), self.round(pt[1]))
  34. return [pt[0] - p0[0], pt[1] - p0[1]]
  35. def _moveTo(self, pt: Tuple[float, float]) -> None:
  36. self._commands.append(("rmoveto", self._p(pt)))
  37. def _lineTo(self, pt: Tuple[float, float]) -> None:
  38. self._commands.append(("rlineto", self._p(pt)))
  39. def _curveToOne(
  40. self,
  41. pt1: Tuple[float, float],
  42. pt2: Tuple[float, float],
  43. pt3: Tuple[float, float],
  44. ) -> None:
  45. _p = self._p
  46. self._commands.append(("rrcurveto", _p(pt1) + _p(pt2) + _p(pt3)))
  47. def _closePath(self) -> None:
  48. pass
  49. def _endPath(self) -> None:
  50. pass
  51. def getCharString(
  52. self,
  53. private: Dict | None = None,
  54. globalSubrs: List | None = None,
  55. optimize: bool = True,
  56. ) -> T2CharString:
  57. commands = self._commands
  58. if optimize:
  59. maxstack = 48 if not self._CFF2 else 513
  60. commands = specializeCommands(
  61. commands, generalizeFirst=False, maxstack=maxstack
  62. )
  63. program = commandsToProgram(commands)
  64. if self._width is not None:
  65. assert (
  66. not self._CFF2
  67. ), "CFF2 does not allow encoding glyph width in CharString."
  68. program.insert(0, otRound(self._width))
  69. if not self._CFF2:
  70. program.append("endchar")
  71. charString = T2CharString(
  72. program=program, private=private, globalSubrs=globalSubrs
  73. )
  74. return charString