151 lines
5.4 KiB
Python
151 lines
5.4 KiB
Python
from __future__ import print_function, division, absolute_import
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from fontTools.misc.py23 import *
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from array import array
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from fontTools.pens.basePen import AbstractPen
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from fontTools.pens.transformPen import TransformPen
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from fontTools.ttLib.tables import ttProgram
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from fontTools.ttLib.tables._g_l_y_f import Glyph
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from fontTools.ttLib.tables._g_l_y_f import GlyphComponent
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from fontTools.ttLib.tables._g_l_y_f import GlyphCoordinates
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__all__ = ["TTGlyphPen"]
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# the max value that can still fit in an F2Dot14:
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# 1.99993896484375
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MAX_F2DOT14 = 0x7FFF / (1 << 14)
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class TTGlyphPen(AbstractPen):
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"""Pen used for drawing to a TrueType glyph.
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If `handleOverflowingTransforms` is True, the components' transform values
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are checked that they don't overflow the limits of a F2Dot14 number:
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-2.0 <= v < +2.0. If any transform value exceeds these, the composite
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glyph is decomposed.
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An exception to this rule is done for values that are very close to +2.0
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(both for consistency with the -2.0 case, and for the relative frequency
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these occur in real fonts). When almost +2.0 values occur (and all other
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values are within the range -2.0 <= x <= +2.0), they are clamped to the
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maximum positive value that can still be encoded as an F2Dot14: i.e.
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1.99993896484375.
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If False, no check is done and all components are translated unmodified
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into the glyf table, followed by an inevitable `struct.error` once an
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attempt is made to compile them.
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"""
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def __init__(self, glyphSet, handleOverflowingTransforms=True):
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self.glyphSet = glyphSet
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self.handleOverflowingTransforms = handleOverflowingTransforms
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self.init()
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def init(self):
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self.points = []
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self.endPts = []
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self.types = []
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self.components = []
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def _addPoint(self, pt, onCurve):
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self.points.append(pt)
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self.types.append(onCurve)
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def _popPoint(self):
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self.points.pop()
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self.types.pop()
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def _isClosed(self):
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return (
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(not self.points) or
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(self.endPts and self.endPts[-1] == len(self.points) - 1))
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def lineTo(self, pt):
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self._addPoint(pt, 1)
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def moveTo(self, pt):
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assert self._isClosed(), '"move"-type point must begin a new contour.'
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self._addPoint(pt, 1)
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def qCurveTo(self, *points):
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assert len(points) >= 1
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for pt in points[:-1]:
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self._addPoint(pt, 0)
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# last point is None if there are no on-curve points
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if points[-1] is not None:
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self._addPoint(points[-1], 1)
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def closePath(self):
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endPt = len(self.points) - 1
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# ignore anchors (one-point paths)
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if endPt == 0 or (self.endPts and endPt == self.endPts[-1] + 1):
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self._popPoint()
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return
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# if first and last point on this path are the same, remove last
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startPt = 0
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if self.endPts:
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startPt = self.endPts[-1] + 1
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if self.points[startPt] == self.points[endPt]:
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self._popPoint()
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endPt -= 1
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self.endPts.append(endPt)
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def endPath(self):
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# TrueType contours are always "closed"
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self.closePath()
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def addComponent(self, glyphName, transformation):
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self.components.append((glyphName, transformation))
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def glyph(self, componentFlags=0x4):
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assert self._isClosed(), "Didn't close last contour."
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if self.handleOverflowingTransforms:
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# we can't encode transform values > 2 or < -2 in F2Dot14,
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# so we must decompose the glyph if any transform exceeds these
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overflowing = any(s > 2 or s < -2
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for (glyphName, transformation) in self.components
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for s in transformation[:4])
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components = []
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for glyphName, transformation in self.components:
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if (self.points or
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(self.handleOverflowingTransforms and overflowing)):
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# can't have both coordinates and components, so decompose
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tpen = TransformPen(self, transformation)
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self.glyphSet[glyphName].draw(tpen)
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continue
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component = GlyphComponent()
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component.glyphName = glyphName
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component.x, component.y = transformation[4:]
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transformation = transformation[:4]
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if transformation != (1, 0, 0, 1):
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if (self.handleOverflowingTransforms and
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any(MAX_F2DOT14 < s <= 2 for s in transformation)):
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# clamp values ~= +2.0 so we can keep the component
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transformation = tuple(MAX_F2DOT14 if MAX_F2DOT14 < s <= 2
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else s for s in transformation)
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component.transform = (transformation[:2], transformation[2:])
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component.flags = componentFlags
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components.append(component)
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glyph = Glyph()
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glyph.coordinates = GlyphCoordinates(self.points)
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glyph.endPtsOfContours = self.endPts
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glyph.flags = array("B", self.types)
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self.init()
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if components:
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glyph.components = components
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glyph.numberOfContours = -1
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else:
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glyph.numberOfContours = len(glyph.endPtsOfContours)
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glyph.program = ttProgram.Program()
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glyph.program.fromBytecode(b"")
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return glyph
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