transformPen: add TransformPointPen, like TransformPen but for point pens

Lib/fontTools/pens/transformPen.py

@@ -1,5 +1,5 @@
 from fontTools.misc.py23 import *
-from fontTools.pens.filterPen import FilterPen
+from fontTools.pens.filterPen import FilterPen, FilterPointPen
 
 
 __all__ = ["TransformPen"]
@@ -55,6 +55,51 @@ class TransformPen(FilterPen):
 		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))