fdb3974dd9
'identifier' param is part of the AbstractPointPen interface.
Even though it is unused by the segment pen protocol, the caller may attempt
to pass it by positional argument instead of keyword argument, e.g.
2920ddd07c/Lib/fontMath/mathGlyph.py (L486)
this patch avoids the resulting TypeError exception
423 lines
12 KiB
Python
423 lines
12 KiB
Python
"""
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=========
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PointPens
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=========
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Where **SegmentPens** have an intuitive approach to drawing
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(if you're familiar with postscript anyway), the **PointPen**
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is geared towards accessing all the data in the contours of
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the glyph. A PointPen has a very simple interface, it just
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steps through all the points in a call from glyph.drawPoints().
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This allows the caller to provide more data for each point.
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For instance, whether or not a point is smooth, and its name.
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"""
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from __future__ import absolute_import, unicode_literals
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from fontTools.pens.basePen import AbstractPen
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import math
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__all__ = [
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"AbstractPointPen",
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"BasePointToSegmentPen",
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"PointToSegmentPen",
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"SegmentToPointPen",
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"GuessSmoothPointPen",
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"ReverseContourPointPen",
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]
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class AbstractPointPen(object):
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"""
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Baseclass for all PointPens.
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"""
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def beginPath(self, identifier=None, **kwargs):
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"""Start a new sub path."""
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raise NotImplementedError
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def endPath(self):
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"""End the current sub path."""
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raise NotImplementedError
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def addPoint(self, pt, segmentType=None, smooth=False, name=None,
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identifier=None, **kwargs):
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"""Add a point to the current sub path."""
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raise NotImplementedError
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def addComponent(self, baseGlyphName, transformation, identifier=None,
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**kwargs):
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"""Add a sub glyph."""
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raise NotImplementedError
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class BasePointToSegmentPen(AbstractPointPen):
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"""
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Base class for retrieving the outline in a segment-oriented
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way. The PointPen protocol is simple yet also a little tricky,
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so when you need an outline presented as segments but you have
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as points, do use this base implementation as it properly takes
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care of all the edge cases.
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"""
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def __init__(self):
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self.currentPath = None
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def beginPath(self, identifier=None, **kwargs):
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assert self.currentPath is None
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self.currentPath = []
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def _flushContour(self, segments):
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"""Override this method.
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It will be called for each non-empty sub path with a list
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of segments: the 'segments' argument.
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The segments list contains tuples of length 2:
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(segmentType, points)
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segmentType is one of "move", "line", "curve" or "qcurve".
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"move" may only occur as the first segment, and it signifies
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an OPEN path. A CLOSED path does NOT start with a "move", in
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fact it will not contain a "move" at ALL.
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The 'points' field in the 2-tuple is a list of point info
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tuples. The list has 1 or more items, a point tuple has
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four items:
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(point, smooth, name, kwargs)
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'point' is an (x, y) coordinate pair.
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For a closed path, the initial moveTo point is defined as
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the last point of the last segment.
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The 'points' list of "move" and "line" segments always contains
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exactly one point tuple.
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"""
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raise NotImplementedError
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def endPath(self):
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assert self.currentPath is not None
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points = self.currentPath
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self.currentPath = None
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if not points:
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return
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if len(points) == 1:
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# Not much more we can do than output a single move segment.
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pt, segmentType, smooth, name, kwargs = points[0]
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segments = [("move", [(pt, smooth, name, kwargs)])]
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self._flushContour(segments)
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return
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segments = []
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if points[0][1] == "move":
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# It's an open contour, insert a "move" segment for the first
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# point and remove that first point from the point list.
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pt, segmentType, smooth, name, kwargs = points[0]
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segments.append(("move", [(pt, smooth, name, kwargs)]))
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points.pop(0)
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else:
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# It's a closed contour. Locate the first on-curve point, and
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# rotate the point list so that it _ends_ with an on-curve
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# point.
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firstOnCurve = None
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for i in range(len(points)):
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segmentType = points[i][1]
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if segmentType is not None:
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firstOnCurve = i
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break
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if firstOnCurve is None:
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# Special case for quadratics: a contour with no on-curve
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# points. Add a "None" point. (See also the Pen protocol's
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# qCurveTo() method and fontTools.pens.basePen.py.)
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points.append((None, "qcurve", None, None, None))
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else:
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points = points[firstOnCurve+1:] + points[:firstOnCurve+1]
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currentSegment = []
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for pt, segmentType, smooth, name, kwargs in points:
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currentSegment.append((pt, smooth, name, kwargs))
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if segmentType is None:
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continue
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segments.append((segmentType, currentSegment))
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currentSegment = []
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self._flushContour(segments)
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def addPoint(self, pt, segmentType=None, smooth=False, name=None,
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identifier=None, **kwargs):
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self.currentPath.append((pt, segmentType, smooth, name, kwargs))
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class PointToSegmentPen(BasePointToSegmentPen):
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"""
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Adapter class that converts the PointPen protocol to the
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(Segment)Pen protocol.
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"""
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def __init__(self, segmentPen, outputImpliedClosingLine=False):
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BasePointToSegmentPen.__init__(self)
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self.pen = segmentPen
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self.outputImpliedClosingLine = outputImpliedClosingLine
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def _flushContour(self, segments):
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assert len(segments) >= 1
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pen = self.pen
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if segments[0][0] == "move":
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# It's an open path.
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closed = False
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points = segments[0][1]
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assert len(points) == 1, "illegal move segment point count: %d" % len(points)
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movePt, smooth, name, kwargs = points[0]
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del segments[0]
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else:
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# It's a closed path, do a moveTo to the last
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# point of the last segment.
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closed = True
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segmentType, points = segments[-1]
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movePt, smooth, name, kwargs = points[-1]
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if movePt is None:
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# quad special case: a contour with no on-curve points contains
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# one "qcurve" segment that ends with a point that's None. We
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# must not output a moveTo() in that case.
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pass
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else:
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pen.moveTo(movePt)
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outputImpliedClosingLine = self.outputImpliedClosingLine
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nSegments = len(segments)
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for i in range(nSegments):
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segmentType, points = segments[i]
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points = [pt for pt, smooth, name, kwargs in points]
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if segmentType == "line":
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assert len(points) == 1, "illegal line segment point count: %d" % len(points)
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pt = points[0]
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if i + 1 != nSegments or outputImpliedClosingLine or not closed:
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pen.lineTo(pt)
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elif segmentType == "curve":
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pen.curveTo(*points)
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elif segmentType == "qcurve":
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pen.qCurveTo(*points)
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else:
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assert 0, "illegal segmentType: %s" % segmentType
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if closed:
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pen.closePath()
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else:
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pen.endPath()
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def addComponent(self, glyphName, transform, identifier=None, **kwargs):
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del identifier # unused
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self.pen.addComponent(glyphName, transform)
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class SegmentToPointPen(AbstractPen):
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"""
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Adapter class that converts the (Segment)Pen protocol to the
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PointPen protocol.
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"""
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def __init__(self, pointPen, guessSmooth=True):
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if guessSmooth:
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self.pen = GuessSmoothPointPen(pointPen)
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else:
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self.pen = pointPen
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self.contour = None
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def _flushContour(self):
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pen = self.pen
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pen.beginPath()
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for pt, segmentType in self.contour:
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pen.addPoint(pt, segmentType=segmentType)
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pen.endPath()
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def moveTo(self, pt):
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self.contour = []
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self.contour.append((pt, "move"))
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def lineTo(self, pt):
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self.contour.append((pt, "line"))
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def curveTo(self, *pts):
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for pt in pts[:-1]:
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self.contour.append((pt, None))
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self.contour.append((pts[-1], "curve"))
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def qCurveTo(self, *pts):
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if pts[-1] is None:
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self.contour = []
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for pt in pts[:-1]:
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self.contour.append((pt, None))
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if pts[-1] is not None:
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self.contour.append((pts[-1], "qcurve"))
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def closePath(self):
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if len(self.contour) > 1 and self.contour[0][0] == self.contour[-1][0]:
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self.contour[0] = self.contour[-1]
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del self.contour[-1]
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else:
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# There's an implied line at the end, replace "move" with "line"
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# for the first point
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pt, tp = self.contour[0]
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if tp == "move":
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self.contour[0] = pt, "line"
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self._flushContour()
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self.contour = None
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def endPath(self):
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self._flushContour()
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self.contour = None
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def addComponent(self, glyphName, transform):
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assert self.contour is None
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self.pen.addComponent(glyphName, transform)
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class GuessSmoothPointPen(AbstractPointPen):
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"""
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Filtering PointPen that tries to determine whether an on-curve point
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should be "smooth", ie. that it's a "tangent" point or a "curve" point.
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"""
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def __init__(self, outPen):
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self._outPen = outPen
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self._points = None
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def _flushContour(self):
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points = self._points
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nPoints = len(points)
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if not nPoints:
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return
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if points[0][1] == "move":
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# Open path.
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indices = range(1, nPoints - 1)
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elif nPoints > 1:
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# Closed path. To avoid having to mod the contour index, we
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# simply abuse Python's negative index feature, and start at -1
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indices = range(-1, nPoints - 1)
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else:
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# closed path containing 1 point (!), ignore.
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indices = []
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for i in indices:
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pt, segmentType, dummy, name, kwargs = points[i]
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if segmentType is None:
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continue
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prev = i - 1
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next = i + 1
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if points[prev][1] is not None and points[next][1] is not None:
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continue
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# At least one of our neighbors is an off-curve point
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pt = points[i][0]
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prevPt = points[prev][0]
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nextPt = points[next][0]
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if pt != prevPt and pt != nextPt:
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dx1, dy1 = pt[0] - prevPt[0], pt[1] - prevPt[1]
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dx2, dy2 = nextPt[0] - pt[0], nextPt[1] - pt[1]
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a1 = math.atan2(dx1, dy1)
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a2 = math.atan2(dx2, dy2)
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if abs(a1 - a2) < 0.05:
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points[i] = pt, segmentType, True, name, kwargs
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for pt, segmentType, smooth, name, kwargs in points:
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self._outPen.addPoint(pt, segmentType, smooth, name, **kwargs)
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def beginPath(self, identifier=None, **kwargs):
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assert self._points is None
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self._points = []
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if identifier is not None:
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kwargs["identifier"] = identifier
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self._outPen.beginPath(**kwargs)
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def endPath(self):
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self._flushContour()
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self._outPen.endPath()
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self._points = None
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def addPoint(self, pt, segmentType=None, smooth=False, name=None,
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identifier=None, **kwargs):
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if identifier is not None:
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kwargs["identifier"] = identifier
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self._points.append((pt, segmentType, False, name, kwargs))
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def addComponent(self, glyphName, transformation, identifier=None, **kwargs):
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assert self._points is None
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if identifier is not None:
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kwargs["identifier"] = identifier
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self._outPen.addComponent(glyphName, transformation, **kwargs)
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class ReverseContourPointPen(AbstractPointPen):
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"""
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This is a PointPen that passes outline data to another PointPen, but
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reversing the winding direction of all contours. Components are simply
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passed through unchanged.
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Closed contours are reversed in such a way that the first point remains
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the first point.
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"""
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def __init__(self, outputPointPen):
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self.pen = outputPointPen
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# a place to store the points for the current sub path
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self.currentContour = None
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def _flushContour(self):
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pen = self.pen
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contour = self.currentContour
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if not contour:
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pen.beginPath(identifier=self.currentContourIdentifier)
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pen.endPath()
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return
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closed = contour[0][1] != "move"
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if not closed:
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lastSegmentType = "move"
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else:
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# Remove the first point and insert it at the end. When
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# the list of points gets reversed, this point will then
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# again be at the start. In other words, the following
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# will hold:
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# for N in range(len(originalContour)):
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# originalContour[N] == reversedContour[-N]
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contour.append(contour.pop(0))
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# Find the first on-curve point.
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firstOnCurve = None
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for i in range(len(contour)):
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if contour[i][1] is not None:
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firstOnCurve = i
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break
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if firstOnCurve is None:
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# There are no on-curve points, be basically have to
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# do nothing but contour.reverse().
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lastSegmentType = None
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else:
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lastSegmentType = contour[firstOnCurve][1]
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contour.reverse()
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if not closed:
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# Open paths must start with a move, so we simply dump
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# all off-curve points leading up to the first on-curve.
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while contour[0][1] is None:
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contour.pop(0)
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pen.beginPath(identifier=self.currentContourIdentifier)
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for pt, nextSegmentType, smooth, name, kwargs in contour:
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if nextSegmentType is not None:
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segmentType = lastSegmentType
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lastSegmentType = nextSegmentType
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else:
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segmentType = None
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pen.addPoint(pt, segmentType=segmentType, smooth=smooth, name=name, **kwargs)
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pen.endPath()
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def beginPath(self, identifier=None, **kwargs):
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assert self.currentContour is None
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self.currentContour = []
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self.currentContourIdentifier = identifier
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self.onCurve = []
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def endPath(self):
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assert self.currentContour is not None
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self._flushContour()
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self.currentContour = None
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def addPoint(self, pt, segmentType=None, smooth=False, name=None, **kwargs):
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self.currentContour.append((pt, segmentType, smooth, name, kwargs))
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def addComponent(self, glyphName, transform, identifier=None, **kwargs):
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assert self.currentContour is None
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self.pen.addComponent(glyphName, transform, identifier=identifier, **kwargs)
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