d76191b0b1
git-svn-id: http://svn.robofab.com/branches/ufo3k@449 b5fa9d6c-a76f-4ffd-b3cb-f825fc41095c
135 lines
4.2 KiB
Python
135 lines
4.2 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 (if you're familiar with postscript anyway), the **PointPen** is geared towards accessing all the data in the contours of the glyph. A PointsPen has a very simple interface, it just steps through all the points in a call from glyph.drawPoints(). This allows the caller to provide more data for each point. For instance, whether or not a point is smooth, and its name.
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"""
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__all__ = ["AbstractPointPen", "BasePointToSegmentPen" ]
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class AbstractPointPen(object):
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"""
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Baseclass for all PointPens.
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- Should move to ufoLib?
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"""
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def beginPath(self):
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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, **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):
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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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"""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):
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"""Start a new sub path."""
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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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"""End the current sub path."""
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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, **kwargs):
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"""Add a point to the current sub path."""
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self.currentPath.append((pt, segmentType, smooth, name, kwargs))
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