Lib/fontTools/pens/transformPen.py

from fontTools.pens.filterPen import FilterPen, FilterPointPen


__all__ = ["TransformPen", "TransformPointPen"]


class TransformPen(FilterPen):

	"""Pen that transforms all coordinates using a Affine transformation,
	and passes them to another pen.
	"""

	def __init__(self, outPen, transformation):
		"""The 'outPen' argument is another pen object. It will receive the
		transformed coordinates. The 'transformation' argument can either
		be a six-tuple, or a fontTools.misc.transform.Transform object.
		"""
		super(TransformPen, self).__init__(outPen)
		if not hasattr(transformation, "transformPoint"):
			from fontTools.misc.transform import Transform
			transformation = Transform(*transformation)
		self._transformation = transformation
		self._transformPoint = transformation.transformPoint
		self._stack = []

	def moveTo(self, pt):
		self._outPen.moveTo(self._transformPoint(pt))

	def lineTo(self, pt):
		self._outPen.lineTo(self._transformPoint(pt))

	def curveTo(self, *points):
		self._outPen.curveTo(*self._transformPoints(points))

	def qCurveTo(self, *points):
		if points[-1] is None:
			points = self._transformPoints(points[:-1]) + [None]
		else:
			points = self._transformPoints(points)
		self._outPen.qCurveTo(*points)

	def _transformPoints(self, points):
		transformPoint = self._transformPoint
		return [transformPoint(pt) for pt in points]

	def closePath(self):
		self._outPen.closePath()

	def endPath(self):
		self._outPen.endPath()

	def addComponent(self, glyphName, transformation):
		transformation = self._transformation.transform(transformation)
		self._outPen.addComponent(glyphName, transformation)


class TransformPointPen(FilterPointPen):
	"""PointPen that transforms all coordinates using a Affine transformation,
	and passes them to another PointPen.

	>>> from fontTools.pens.recordingPen import RecordingPointPen
	>>> rec = RecordingPointPen()
	>>> pen = TransformPointPen(rec, (2, 0, 0, 2, -10, 5))
	>>> v = iter(rec.value)
	>>> pen.beginPath(identifier="contour-0")
	>>> next(v)
	('beginPath', (), {'identifier': 'contour-0'})
	>>> pen.addPoint((100, 100), "line")
	>>> next(v)
	('addPoint', ((190, 205), 'line', False, None), {})
	>>> pen.endPath()
	>>> next(v)
	('endPath', (), {})
	>>> pen.addComponent("a", (1, 0, 0, 1, -10, 5), identifier="component-0")
	>>> next(v)
	('addComponent', ('a', <Transform [2 0 0 2 -30 15]>), {'identifier': 'component-0'})
	"""

	def __init__(self, outPointPen, transformation):
		"""The 'outPointPen' argument is another point pen object.
		It will receive the transformed coordinates.
		The 'transformation' argument can either be a six-tuple, or a
		fontTools.misc.transform.Transform object.
		"""
		super().__init__(outPointPen)
		if not hasattr(transformation, "transformPoint"):
			from fontTools.misc.transform import Transform
			transformation = Transform(*transformation)
		self._transformation = transformation
		self._transformPoint = transformation.transformPoint

	def addPoint(self, pt, segmentType=None, smooth=False, name=None, **kwargs):
		self._outPen.addPoint(
			self._transformPoint(pt), segmentType, smooth, name, **kwargs
		)

	def addComponent(self, baseGlyphName, transformation, **kwargs):
		transformation = self._transformation.transform(transformation)
		self._outPen.addComponent(baseGlyphName, transformation, **kwargs)


if __name__ == "__main__":
	from fontTools.pens.basePen import _TestPen
	pen = TransformPen(_TestPen(None), (2, 0, 0.5, 2, -10, 0))
	pen.moveTo((0, 0))
	pen.lineTo((0, 100))
	pen.curveTo((50, 75), (60, 50), (50, 25), (0, 0))
	pen.closePath()