def _set_segments(glyph, segments, reverse_direction):
"""Draw segments as extracted by GetSegmentsPen back to a glyph."""
glyph.clearContours()
pen = glyph.getPen()
if reverse_direction:
pen = ReverseContourPen(pen)
for tag, args in segments:
if tag == 'move':
pen.moveTo(*args)
elif tag == 'line':
pen.lineTo(*args)
elif tag == 'curve':
pen.curveTo(*args[1:])
elif tag == 'qcurve':
pen.qCurveTo(*args[1:])
elif tag == 'close':
pen.closePath()
elif tag == 'end':
pen.endPath()
else:
raise AssertionError('Unhandled segment type "%s"' % tag)
class Cu2QuPen(AbstractPen):
""" A filter pen to convert cubic bezier curves to quadratic b-splines
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 quadratic segments.
ignore_single_points: don't emit contours containing only a single point
NOTE: The "ignore_single_points" argument is deprecated since v1.3.0,
which dropped Robofab subpport. It's no longer needed to special-case
UFO2-style anchors (aka "named points") when using ufoLib >= 2.0,
as these are no longer drawn onto pens as single-point contours,
but are handled separately as anchors.
"""
def __init__(self,
other_pen,
max_err,
reverse_direction=False,
stats=None,
ignore_single_points=False):
if reverse_direction:
self.pen = ReverseContourPen(other_pen)
else:
self.pen = other_pen
self.max_err = max_err
self.stats = stats
if ignore_single_points:
import warnings
warnings.warn(
"ignore_single_points is deprecated and "
"will be removed in future versions",
UserWarning,
stacklevel=2)
self.ignore_single_points = ignore_single_points
self.start_pt = None
self.current_pt = None
def _check_contour_is_open(self):
if self.current_pt is None:
raise AssertionError("moveTo is required")
def _check_contour_is_closed(self):
if self.current_pt is not None:
raise AssertionError("closePath or endPath is required")
def _add_moveTo(self):
if self.start_pt is not None:
self.pen.moveTo(self.start_pt)
self.start_pt = None
def moveTo(self, pt):
self._check_contour_is_closed()
self.start_pt = self.current_pt = pt
if not self.ignore_single_points:
self._add_moveTo()
def lineTo(self, pt):
self._check_contour_is_open()
self._add_moveTo()
self.pen.lineTo(pt)
self.current_pt = pt
def qCurveTo(self, *points):
self._check_contour_is_open()
n = len(points)
if n == 1:
self.lineTo(points[0])
elif n > 1:
self._add_moveTo()
self.pen.qCurveTo(*points)
self.current_pt = points[-1]
else:
raise AssertionError("illegal qcurve segment point count: %d" % n)
def _curve_to_quadratic(self, pt1, pt2, pt3):
curve = (self.current_pt, pt1, pt2, pt3)
quadratic = curve_to_quadratic(curve, self.max_err)
if self.stats is not None:
n = str(len(quadratic) - 2)
self.stats[n] = self.stats.get(n, 0) + 1
self.qCurveTo(*quadratic[1:])
def curveTo(self, *points):
self._check_contour_is_open()
n = len(points)
if n == 3:
# this is the most common case, so we special-case it
self._curve_to_quadratic(*points)
elif n > 3:
for segment in decomposeSuperBezierSegment(points):
self._curve_to_quadratic(*segment)
elif n == 2:
self.qCurveTo(*points)
elif n == 1:
self.lineTo(points[0])
else:
raise AssertionError("illegal curve segment point count: %d" % n)
def closePath(self):
self._check_contour_is_open()
if self.start_pt is None:
# if 'start_pt' is _not_ None, we are ignoring single-point paths
self.pen.closePath()
self.current_pt = self.start_pt = None
def endPath(self):
self._check_contour_is_open()
if self.start_pt is None:
self.pen.endPath()
self.current_pt = self.start_pt = None
def addComponent(self, glyphName, transformation):
self._check_contour_is_closed()
self.pen.addComponent(glyphName, transformation)