diff --git a/Lib/fontTools/pens/qu2cuPen.py b/Lib/fontTools/pens/qu2cuPen.py new file mode 100644 index 000000000..9629632a7 --- /dev/null +++ b/Lib/fontTools/pens/qu2cuPen.py @@ -0,0 +1,62 @@ +# Copyright 2016 Google Inc. All Rights Reserved. +# Copyright 2023 Behdad Esfahbod. All Rights Reserved. +# +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +from fontTools.qu2cu import quadratic_to_curve +from fontTools.pens.filterPen import FilterPen +from fontTools.pens.reverseContourPen import ReverseContourPen + + +class Qu2CuPen(FilterPen): + """A filter pen to convert quadratic bezier splines to cubic curves + using the FontTools SegmentPen protocol. + + Args: + + other_pen: another SegmentPen used to draw the transformed outline. + max_err: maximum approximation error in font units. For optimal results, + if you know the UPEM of the font, we recommend setting this to a + value equal, or close to UPEM / 1000. + reverse_direction: flip the contours' direction but keep starting point. + stats: a dictionary counting the point numbers of cubic segments. + """ + + def __init__( + self, + other_pen, + max_err, + reverse_direction=False, + stats=None, + ): + if reverse_direction: + other_pen = ReverseContourPen(other_pen) + super().__init__(other_pen) + self.max_err = max_err + self.stats = stats + + def _quadratic_to_curve(self, points): + quadratics = (self.current_pt,) + points + curves = quadratic_to_curves(quadratics, self.max_err) + if self.stats is not None: + n = str(len(curves)) + self.stats[n] = self.stats.get(n, 0) + 1 + for curve in curves: + self.curveTo(*curve[1:]) + + def qCurveTo(self, *points): + n = len(points) + if n < 2: + self.lineTo(*points) + else: + self._quadratic_to_curve(points)