ReverseContourPen drops points

[jamesgk]

The following test will fail:

class TestCu2QuReverseContourPen(unittest.TestCase):
    def _draw_test_contour(self, pen):
        pen.moveTo((848, 348))
        pen.lineTo((848, 348))
        pen.qCurveTo((848, 526), (649, 704), (449, 704))
        pen.qCurveTo((449, 704), (248, 704), (50, 526), (50, 348))
        pen.lineTo((50, 348))
        pen.qCurveTo((50, 348), (50, 171), (248, -3), (449, -3))
        pen.qCurveTo((449, -3), (649, -3), (848, 171), (848, 348))
        pen.closePath()

    def test_duplicate_points_remain(self):
        pen1 = DummyPen()
        pen2 = DummyPen()
        self._draw_test_contour(pen1)
        self._draw_test_contour(ReverseContourPen(pen2))
        self.assertEqual(
            len(pen1.commands), len(pen2.commands),
            '\n%s\nreversed to:\n%s;\nsome points dropped.' % (pen1, pen2))

[anthrotype]

Ouch. Does it happen with the ReverseContourPointPen as well?
If not, then it might be one of the Point->Segment->Point converter pens...

[anthrotype]

This one passes, so it must not be the original ReverseContourPointPen that's dropping the point, but something else in the converter pens...

class TestCu2QuReverseContourPointPen(unittest.TestCase):
    def _draw_test_contour(self, pen):
        pen.beginPath()
        pen.addPoint((848, 348), segmentType='line')
        pen.addPoint((848, 348), segmentType='line')
        pen.addPoint((848, 526))
        pen.addPoint((649, 704))
        pen.addPoint((449, 704), segmentType='qcurve')
        pen.addPoint((449, 704))
        pen.addPoint((248, 704))
        pen.addPoint((50, 526))
        pen.addPoint((50, 348), segmentType='qcurve')
        pen.addPoint((50, 348), segmentType='line')
        pen.addPoint((50, 348))
        pen.addPoint((50, 171))
        pen.addPoint((248, -3))
        pen.addPoint((449, -3), segmentType='qcurve')
        pen.addPoint((449, -3))
        pen.addPoint((649, -3))
        pen.addPoint((848, 171))
        pen.addPoint((848, 348), segmentType='qcurve')
        pen.endPath()

    def test_duplicate_points_remain(self):
        pen1 = DummyPointPen()
        pen2 = DummyPointPen()
        self._draw_test_contour(pen1)
        self._draw_test_contour(ReverseContourPointPen(pen2))
        self.assertEqual(
            len(pen1.commands), len(pen2.commands),
            '\n%s\nreversed to:\n%s;\nsome points dropped.' % (pen1, pen2))

[anthrotype]

It turns out it was the PointToSegmentPen which defaults to outputImpliedClosingLine=False. Making that True would fix this.
Even better, cu2qu could now use fontTools' reverseContourPen directly, without wrapping ufoLib's point pen with the convert pens.
I fixed this issue in fonttools/fonttools#1080, I will update cu2qu soon after releasing the next fonttools.

[anthrotype]

not so fast. let's keep this open until we update cu2qu's fonttools requirement.