102 lines
3.4 KiB
Python
102 lines
3.4 KiB
Python
#! /usr/bin/env python
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#
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# Copyright 2015 Google Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""
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Converts a cubic bezier curve to a quadratic spline with
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exactly two off curve points.
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"""
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import numpy
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from numpy import array,cross,dot
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from fontTools.misc import bezierTools
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from robofab.objects.objectsRF import RSegment
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def replaceSegments(contour, segments):
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while len(contour):
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contour.removeSegment(0)
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for s in segments:
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contour.appendSegment(s.type, [(p.x, p.y) for p in s.points], s.smooth)
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def calcIntersect(a,b,c,d):
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numpy.seterr(all='raise')
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e = b-a
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f = d-c
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p = array([-e[1], e[0]])
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try:
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h = dot((a-c),p) / dot(f,p)
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except:
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print a,b,c,d
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raise
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return c + dot(f,h)
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def simpleConvertToQuadratic(p0,p1,p2,p3):
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p = [array(i.x,i.y) for i in [p0,p1,p2,p3]]
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off = calcIntersect(p[0],p[1],p[2],p[3])
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# OFFCURVE_VECTOR_CORRECTION = -.015
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OFFCURVE_VECTOR_CORRECTION = 0
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def convertToQuadratic(p0,p1,p2,p3):
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# TODO: test for accuracy and subdivide further if needed
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p = [(i.x,i.y) for i in [p0,p1,p2,p3]]
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# if p[0][0] == p[1][0] and p[0][0] == p[2][0] and p[0][0] == p[2][0] and p[0][0] == p[3][0]:
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# return (p[0],p[1],p[2],p[3])
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# if p[0][1] == p[1][1] and p[0][1] == p[2][1] and p[0][1] == p[2][1] and p[0][1] == p[3][1]:
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# return (p[0],p[1],p[2],p[3])
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seg1,seg2 = bezierTools.splitCubicAtT(p[0], p[1], p[2], p[3], .5)
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pts1 = [array([i[0], i[1]]) for i in seg1]
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pts2 = [array([i[0], i[1]]) for i in seg2]
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on1 = seg1[0]
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on2 = seg2[3]
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try:
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off1 = calcIntersect(pts1[0], pts1[1], pts1[2], pts1[3])
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off2 = calcIntersect(pts2[0], pts2[1], pts2[2], pts2[3])
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except:
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return (p[0],p[1],p[2],p[3])
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off1 = (on1 - off1) * OFFCURVE_VECTOR_CORRECTION + off1
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off2 = (on2 - off2) * OFFCURVE_VECTOR_CORRECTION + off2
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return (on1,off1,off2,on2)
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def cubicSegmentToQuadratic(c,sid):
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segment = c[sid]
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if (segment.type != "curve"):
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print "Segment type not curve"
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return
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#pSegment,junk = getPrevAnchor(c,sid)
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pSegment = c[sid-1] #assumes that a curve type will always be proceeded by another point on the same contour
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points = convertToQuadratic(pSegment.points[-1],segment.points[0],
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segment.points[1],segment.points[2])
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return RSegment(
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'qcurve', [[int(i) for i in p] for p in points[1:]], segment.smooth)
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def glyphCurvesToQuadratic(g):
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for c in g:
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segments = []
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for i in range(len(c)):
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s = c[i]
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if s.type == "curve":
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try:
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segments.append(cubicSegmentToQuadratic(c, i))
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except Exception:
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print g.name, i
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raise
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else:
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segments.append(s)
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replaceSegments(c, segments)
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