601 lines
22 KiB
Python
601 lines
22 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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import math
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from typing import Any, Optional, Tuple, Dict
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from fontTools.misc.loggingTools import LogMixin
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from fontTools.pens.basePen import AbstractPen, MissingComponentError, PenError
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from fontTools.misc.transform import DecomposedTransform, Identity
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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:
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"""Baseclass for all PointPens."""
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def beginPath(self, identifier: Optional[str] = None, **kwargs: Any) -> None:
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"""Start a new sub path."""
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raise NotImplementedError
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def endPath(self) -> None:
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"""End the current sub path."""
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raise NotImplementedError
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def addPoint(
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self,
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pt: Tuple[float, float],
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segmentType: Optional[str] = None,
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smooth: bool = False,
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name: Optional[str] = None,
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identifier: Optional[str] = None,
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**kwargs: Any,
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) -> None:
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"""Add a point to the current sub path."""
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raise NotImplementedError
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def addComponent(
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self,
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baseGlyphName: str,
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transformation: Tuple[float, float, float, float, float, float],
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identifier: Optional[str] = None,
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**kwargs: Any,
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) -> None:
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"""Add a sub glyph."""
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raise NotImplementedError
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def addVarComponent(
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self,
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glyphName: str,
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transformation: DecomposedTransform,
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location: Dict[str, float],
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identifier: Optional[str] = None,
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**kwargs: Any,
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) -> None:
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"""Add a VarComponent sub glyph. The 'transformation' argument
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must be a DecomposedTransform from the fontTools.misc.transform module,
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and the 'location' argument must be a dictionary mapping axis tags
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to their locations.
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"""
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# ttGlyphSet decomposes for us
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raise AttributeError
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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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if self.currentPath is not None:
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raise PenError("Path already begun.")
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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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if self.currentPath is None:
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raise PenError("Path not begun.")
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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(
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self, pt, segmentType=None, smooth=False, name=None, identifier=None, **kwargs
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):
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if self.currentPath is None:
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raise PenError("Path not begun")
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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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NOTE: The segment pen does not support and will drop point names, identifiers
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and kwargs.
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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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if not segments:
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raise PenError("Must have at least one segment.")
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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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if len(points) != 1:
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raise PenError(f"Illegal move segment point count: {len(points)}")
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movePt, _, _, _ = 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, _, _, _ = 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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lastPt = movePt
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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, _, _, _ in points]
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if segmentType == "line":
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if len(points) != 1:
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raise PenError(f"Illegal line segment point count: {len(points)}")
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pt = points[0]
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# For closed contours, a 'lineTo' is always implied from the last oncurve
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# point to the starting point, thus we can omit it when the last and
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# starting point don't overlap.
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# However, when the last oncurve point is a "line" segment and has same
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# coordinates as the starting point of a closed contour, we need to output
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# the closing 'lineTo' explicitly (regardless of the value of the
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# 'outputImpliedClosingLine' option) in order to disambiguate this case from
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# the implied closing 'lineTo', otherwise the duplicate point would be lost.
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# See https://github.com/googlefonts/fontmake/issues/572.
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if (
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i + 1 != nSegments
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or outputImpliedClosingLine
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or not closed
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or pt == lastPt
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):
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pen.lineTo(pt)
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lastPt = pt
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elif segmentType == "curve":
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pen.curveTo(*points)
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lastPt = points[-1]
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elif segmentType == "qcurve":
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pen.qCurveTo(*points)
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lastPt = points[-1]
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else:
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raise PenError(f"Illegal segmentType: {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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del kwargs # 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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if self.contour is None:
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raise PenError("Contour missing required initial moveTo")
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self.contour.append((pt, "line"))
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def curveTo(self, *pts):
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if not pts:
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raise TypeError("Must pass in at least one point")
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if self.contour is None:
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raise PenError("Contour missing required initial moveTo")
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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 not pts:
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raise TypeError("Must pass in at least one point")
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if pts[-1] is None:
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self.contour = []
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else:
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if self.contour is None:
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raise PenError("Contour missing required initial moveTo")
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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 self.contour is None:
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raise PenError("Contour missing required initial moveTo")
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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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if self.contour is None:
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raise PenError("Contour missing required initial moveTo")
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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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if self.contour is not None:
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raise PenError("Components must be added before or after contours")
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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, error=0.05):
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self._outPen = outPen
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self._error = error
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self._points = None
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def _flushContour(self):
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if self._points is None:
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raise PenError("Path not begun")
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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, _, 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(dy1, dx1)
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a2 = math.atan2(dy2, dx2)
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if abs(a1 - a2) < self._error:
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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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if self._points is not None:
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raise PenError("Path already begun")
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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(
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self, pt, segmentType=None, smooth=False, name=None, identifier=None, **kwargs
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):
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if self._points is None:
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raise PenError("Path not begun")
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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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if self._points is not None:
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raise PenError("Components must be added before or after contours")
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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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def addVarComponent(
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self, glyphName, transformation, location, identifier=None, **kwargs
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):
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if self._points is not None:
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raise PenError("VarComponents must be added before or after contours")
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if identifier is not None:
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kwargs["identifier"] = identifier
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self._outPen.addVarComponent(glyphName, transformation, location, **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(
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pt, segmentType=segmentType, smooth=smooth, name=name, **kwargs
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)
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pen.endPath()
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def beginPath(self, identifier=None, **kwargs):
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if self.currentContour is not None:
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raise PenError("Path already begun")
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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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if self.currentContour is None:
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raise PenError("Path not begun")
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self._flushContour()
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self.currentContour = None
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def addPoint(
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self, pt, segmentType=None, smooth=False, name=None, identifier=None, **kwargs
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):
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if self.currentContour is None:
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raise PenError("Path not begun")
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if identifier is not None:
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kwargs["identifier"] = identifier
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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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if self.currentContour is not None:
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|
raise PenError("Components must be added before or after contours")
|
|
self.pen.addComponent(glyphName, transform, identifier=identifier, **kwargs)
|
|
|
|
|
|
class DecomposingPointPen(LogMixin, AbstractPointPen):
|
|
"""Implements a 'addComponent' method that decomposes components
|
|
(i.e. draws them onto self as simple contours).
|
|
It can also be used as a mixin class (e.g. see DecomposingRecordingPointPen).
|
|
|
|
You must override beginPath, addPoint, endPath. You may
|
|
additionally override addVarComponent and addComponent.
|
|
|
|
By default a warning message is logged when a base glyph is missing;
|
|
set the class variable ``skipMissingComponents`` to False if you want
|
|
all instances of a sub-class to raise a :class:`MissingComponentError`
|
|
exception by default.
|
|
"""
|
|
|
|
skipMissingComponents = True
|
|
# alias error for convenience
|
|
MissingComponentError = MissingComponentError
|
|
|
|
def __init__(
|
|
self,
|
|
glyphSet,
|
|
*args,
|
|
skipMissingComponents=None,
|
|
reverseFlipped=False,
|
|
**kwargs,
|
|
):
|
|
"""Takes a 'glyphSet' argument (dict), in which the glyphs that are referenced
|
|
as components are looked up by their name.
|
|
|
|
If the optional 'reverseFlipped' argument is True, components whose transformation
|
|
matrix has a negative determinant will be decomposed with a reversed path direction
|
|
to compensate for the flip.
|
|
|
|
The optional 'skipMissingComponents' argument can be set to True/False to
|
|
override the homonymous class attribute for a given pen instance.
|
|
"""
|
|
super().__init__(*args, **kwargs)
|
|
self.glyphSet = glyphSet
|
|
self.skipMissingComponents = (
|
|
self.__class__.skipMissingComponents
|
|
if skipMissingComponents is None
|
|
else skipMissingComponents
|
|
)
|
|
self.reverseFlipped = reverseFlipped
|
|
|
|
def addComponent(self, baseGlyphName, transformation, identifier=None, **kwargs):
|
|
"""Transform the points of the base glyph and draw it onto self.
|
|
|
|
The `identifier` parameter and any extra kwargs are ignored.
|
|
"""
|
|
from fontTools.pens.transformPen import TransformPointPen
|
|
|
|
try:
|
|
glyph = self.glyphSet[baseGlyphName]
|
|
except KeyError:
|
|
if not self.skipMissingComponents:
|
|
raise MissingComponentError(baseGlyphName)
|
|
self.log.warning(
|
|
"glyph '%s' is missing from glyphSet; skipped" % baseGlyphName
|
|
)
|
|
else:
|
|
pen = self
|
|
if transformation != Identity:
|
|
pen = TransformPointPen(pen, transformation)
|
|
if self.reverseFlipped:
|
|
# if the transformation has a negative determinant, it will
|
|
# reverse the contour direction of the component
|
|
a, b, c, d = transformation[:4]
|
|
det = a * d - b * c
|
|
if a * d - b * c < 0:
|
|
pen = ReverseContourPointPen(pen)
|
|
glyph.drawPoints(pen)
|