psfexpandstroke.py

#!/usr/bin/env python
from __future__ import unicode_literals
'''Expands an unclosed UFO stroke font into monoline forms with a fixed width'''
__url__ = 'http://github.com/silnrsi/pysilfont'
__copyright__ = 'Copyright (c) 2017 SIL International (http://www.sil.org), based on outlinerRoboFontExtension Copyright (c) 2016 Frederik Berlaen'
__license__ = 'Released under the MIT License (http://opensource.org/licenses/MIT)'
__author__ = 'Victor Gaultney'

# Usage: psfexpandstroke ifont ofont expansion
# expansion is the number of units added to each side of the stroke

# To Do
# - Simplify to assume round caps and corners

# main input, output, and execution handled by pysilfont framework
from silfont.core import execute

from fontTools.pens.basePen import BasePen
from fontTools.misc.bezierTools import splitCubicAtT
from robofab.world import OpenFont
from robofab.pens.pointPen import AbstractPointPen
from robofab.pens.reverseContourPointPen import ReverseContourPointPen
from robofab.pens.adapterPens import PointToSegmentPen

from defcon import Glyph

from math import sqrt, cos, sin, acos, asin, degrees, radians, pi

suffix = '_expanded'
argspec = [
   ('ifont',{'help': 'Input font file'}, {'type': 'filename'}),
   ('ofont',{'help': 'Output font file','nargs': '?' }, {'type': 'filename', 'def': "_"+suffix}),
   ('thickness',{'help': 'Stroke thickness'}, {}),
   ('-l','--log',{'help': 'Log file'}, {'type': 'outfile', 'def': suffix+'.log'})]


# The following functions are straight from outlinerRoboFontExtension

def roundFloat(f):
    error = 1000000.
    return round(f*error)/error

def checkSmooth(firstAngle, lastAngle):
    if firstAngle is None or lastAngle is None:
        return True
    error = 4
    firstAngle = degrees(firstAngle)
    lastAngle = degrees(lastAngle)

    if int(firstAngle) + error >= int(lastAngle) >= int(firstAngle) - error:
        return True
    return False

def checkInnerOuter(firstAngle, lastAngle):
    if firstAngle is None or lastAngle is None:
        return True
    dirAngle = degrees(firstAngle) - degrees(lastAngle)

    if dirAngle > 180:
        dirAngle = 180 - dirAngle
    elif dirAngle < -180:
        dirAngle = -180 - dirAngle

    if dirAngle > 0:
        return True

    if dirAngle <= 0:
        return False


def interSect((seg1s, seg1e), (seg2s, seg2e)):
    denom = (seg2e.y - seg2s.y)*(seg1e.x - seg1s.x) - (seg2e.x - seg2s.x)*(seg1e.y - seg1s.y)
    if roundFloat(denom) == 0:
        # print 'parallel: %s' % denom
        return None
    uanum = (seg2e.x - seg2s.x)*(seg1s.y - seg2s.y) - (seg2e.y - seg2s.y)*(seg1s.x - seg2s.x)
    ubnum = (seg1e.x - seg1s.x)*(seg1s.y - seg2s.y) - (seg1e.y - seg1s.y)*(seg1s.x - seg2s.x)
    ua = uanum / denom
    # ub = ubnum / denom
    x = seg1s.x + ua*(seg1e.x - seg1s.x)
    y = seg1s.y + ua*(seg1e.y - seg1s.y)
    return MathPoint(x, y)


def pointOnACurve((x1, y1), (cx1, cy1), (cx2, cy2), (x2, y2), value):
    dx = x1
    cx = (cx1 - dx) * 3.0
    bx = (cx2 - cx1) * 3.0 - cx
    ax = x2 - dx - cx - bx
    dy = y1
    cy = (cy1 - dy) * 3.0
    by = (cy2 - cy1) * 3.0 - cy
    ay = y2 - dy - cy - by
    mx = ax*(value)**3 + bx*(value)**2 + cx*(value) + dx
    my = ay*(value)**3 + by*(value)**2 + cy*(value) + dy
    return MathPoint(mx, my)


class MathPoint(object):

    def __init__(self, x, y=None):
        if y is None:
            x, y = x
        self.x = x
        self.y = y

    def __repr__(self):
        return "<MathPoint x:%s y:%s>" % (self.x, self.y)

    def __getitem__(self, index):
        if index == 0:
            return self.x
        if index == 1:
            return self.y
        raise IndexError

    def __iter__(self):
        for value in [self.x, self.y]:
            yield value

    def __add__(self, p):  # p+ p
        if not isinstance(p, self.__class__):
            return self.__class__(self.x + p, self.y + p)
        return self.__class__(self.x + p.x, self.y + p.y)

    def __sub__(self, p):  # p - p
        if not isinstance(p, self.__class__):
            return self.__class__(self.x - p, self.y - p)
        return self.__class__(self.x - p.x, self.y - p.y)

    def __mul__(self, p):  # p * p
        if not isinstance(p, self.__class__):
            return self.__class__(self.x * p, self.y * p)
        return self.__class__(self.x * p.x, self.y * p.y)

    def __div__(self, p):
        if not isinstance(p, self.__class__):
            return self.__class__(self.x / p, self.y / p)
        return self.__class__(self.x / p.x, self.y / p.y)

    def __eq__(self, p):  # if p == p
        if not isinstance(p, self.__class__):
            return False
        return roundFloat(self.x) == roundFloat(p.x) and roundFloat(self.y) == roundFloat(p.y)

    def __ne__(self, p):  # if p != p
        return not self.__eq__(p)

    def copy(self):
        return self.__class__(self.x, self.y)

    def round(self):
        self.x = round(self.x)
        self.y = round(self.y)

    def distance(self, p):
        return sqrt((p.x - self.x)**2 + (p.y - self.y)**2)

    def angle(self, other, add=90):
        # returns the angle of a Line in radians
        b = other.x - self.x
        a = other.y - self.y
        c = sqrt(a**2 + b**2)
        if c == 0:
            return None
        if add is None:
            return b/c
        cosAngle = degrees(acos(b/c))
        sinAngle = degrees(asin(a/c))
        if sinAngle < 0:
            cosAngle = 360 - cosAngle
        return radians(cosAngle + add)


class CleanPointPen(AbstractPointPen):

    def __init__(self, pointPen):
        self.pointPen = pointPen
        self.currentContour = None

    def processContour(self):
        pointPen = self.pointPen
        contour = self.currentContour

        index = 0
        prevAngle = None
        toRemove = []
        for data in contour:
            if data["segmentType"] in ["line", "move"]:
                prevPoint = contour[index-1]
                if prevPoint["segmentType"] in ["line", "move"]:
                    angle = MathPoint(data["point"]).angle(MathPoint(prevPoint["point"]))
                    if prevAngle is not None and angle is not None and roundFloat(prevAngle) == roundFloat(angle):
                        prevPoint["uniqueID"] = id(prevPoint)
                        toRemove.append(prevPoint)
                    prevAngle = angle
                else:
                    prevAngle = None
            else:
                prevAngle = None
            index += 1

        for data in toRemove:
            contour.remove(data)

        pointPen.beginPath()
        for data in contour:
            pointPen.addPoint(data["point"], **data)
        pointPen.endPath()

    def beginPath(self):
        assert self.currentContour is None
        self.currentContour = []
        self.onCurve = []

    def endPath(self):
        assert self.currentContour is not None
        self.processContour()
        self.currentContour = None

    def addPoint(self, pt, segmentType=None, smooth=False, name=None, **kwargs):
        data = dict(point=pt, segmentType=segmentType, smooth=smooth, name=name)
        data.update(kwargs)
        self.currentContour.append(data)

    def addComponent(self, glyphName, transform):
        assert self.currentContour is None
        self.pointPen.addComponent(glyphName, transform)

# The following class has been been adjusted to work around how outline types use closePath() and endPath(),
# to remove unneeded bits, and hard-code some assumptions.

class OutlinePen(BasePen):

    pointClass = MathPoint
    magicCurve = 0.5522847498

    def __init__(self, glyphSet, offset=10, contrast=0, contrastAngle=0, connection="round", cap="round", miterLimit=None, optimizeCurve=True):
        BasePen.__init__(self, glyphSet)

        self.offset = abs(offset)
        self.contrast = abs(contrast)
        self.contrastAngle = contrastAngle
        self._inputmiterLimit = miterLimit
        if miterLimit is None:
            miterLimit = self.offset * 2
        self.miterLimit = abs(miterLimit)

        self.optimizeCurve = optimizeCurve

        self.connectionCallback = getattr(self, "connection%s" % (connection.title()))
        self.capCallback = getattr(self, "cap%s" % (cap.title()))

        self.originalGlyph = Glyph()
        self.originalPen = self.originalGlyph.getPen()

        self.outerGlyph = Glyph()
        self.outerPen = self.outerGlyph.getPen()
        self.outerCurrentPoint = None
        self.outerFirstPoint = None
        self.outerPrevPoint = None

        self.innerGlyph = Glyph()
        self.innerPen = self.innerGlyph.getPen()
        self.innerCurrentPoint = None
        self.innerFirstPoint = None
        self.innerPrevPoint = None

        self.prevPoint = None
        self.firstPoint = None
        self.firstAngle = None
        self.prevAngle = None

        self.shouldHandleMove = True

        self.components = []

        self.drawSettings()

    def _moveTo(self, (x, y)):
        if self.offset == 0:
            self.outerPen.moveTo((x, y))
            self.innerPen.moveTo((x, y))
            return
        self.originalPen.moveTo((x, y))

        p = self.pointClass(x, y)
        self.prevPoint = p
        self.firstPoint = p
        self.shouldHandleMove = True

    def _lineTo(self, (x, y)):
        if self.offset == 0:
            self.outerPen.lineTo((x, y))
            self.innerPen.lineTo((x, y))
            return
        self.originalPen.lineTo((x, y))

        currentPoint = self.pointClass(x, y)
        if currentPoint == self.prevPoint:
            return

        self.currentAngle = self.prevPoint.angle(currentPoint)
        thickness = self.getThickness(self.currentAngle)
        self.innerCurrentPoint = self.prevPoint - self.pointClass(cos(self.currentAngle), sin(self.currentAngle)) * thickness
        self.outerCurrentPoint = self.prevPoint + self.pointClass(cos(self.currentAngle), sin(self.currentAngle)) * thickness

        if self.shouldHandleMove:
            self.shouldHandleMove = False

            self.innerPen.moveTo(self.innerCurrentPoint)
            self.innerFirstPoint = self.innerCurrentPoint

            self.outerPen.moveTo(self.outerCurrentPoint)
            self.outerFirstPoint = self.outerCurrentPoint

            self.firstAngle = self.currentAngle
        else:
            self.buildConnection()

        self.innerCurrentPoint = currentPoint - self.pointClass(cos(self.currentAngle), sin(self.currentAngle)) * thickness
        self.innerPen.lineTo(self.innerCurrentPoint)
        self.innerPrevPoint = self.innerCurrentPoint

        self.outerCurrentPoint = currentPoint + self.pointClass(cos(self.currentAngle), sin(self.currentAngle)) * thickness
        self.outerPen.lineTo(self.outerCurrentPoint)
        self.outerPrevPoint = self.outerCurrentPoint

        self.prevPoint = currentPoint
        self.prevAngle = self.currentAngle

    def _curveToOne(self, (x1, y1), (x2, y2), (x3, y3)):
        if self.optimizeCurve:
            curves = splitCubicAtT(self.prevPoint, (x1, y1), (x2, y2), (x3, y3), .5)
        else:
            curves = [(self.prevPoint, (x1, y1), (x2, y2), (x3, y3))]
        for curve in curves:
            p1, h1, h2, p2 = curve
            self._processCurveToOne(h1, h2, p2)

    def _processCurveToOne(self, (x1, y1), (x2, y2), (x3, y3)):
        if self.offset == 0:
            self.outerPen.curveTo((x1, y1), (x2, y2), (x3, y3))
            self.innerPen.curveTo((x1, y1), (x2, y2), (x3, y3))
            return
        self.originalPen.curveTo((x1, y1), (x2, y2), (x3, y3))

        p1 = self.pointClass(x1, y1)
        p2 = self.pointClass(x2, y2)
        p3 = self.pointClass(x3, y3)

        if p1 == self.prevPoint:
            p1 = pointOnACurve(self.prevPoint, p1, p2, p3, 0.01)
        if p2 == p3:
            p2 = pointOnACurve(self.prevPoint, p1, p2, p3, 0.99)

        a1 = self.prevPoint.angle(p1)
        a2 = p2.angle(p3)

        self.currentAngle = a1
        tickness1 = self.getThickness(a1)
        tickness2 = self.getThickness(a2)

        a1bis = self.prevPoint.angle(p1, 0)
        a2bis = p3.angle(p2, 0)
        intersectPoint = interSect((self.prevPoint, self.prevPoint + self.pointClass(cos(a1), sin(a1)) * 100),
                                   (p3, p3 + self.pointClass(cos(a2), sin(a2)) * 100))
        self.innerCurrentPoint = self.prevPoint - self.pointClass(cos(a1), sin(a1)) * tickness1
        self.outerCurrentPoint = self.prevPoint + self.pointClass(cos(a1), sin(a1)) * tickness1

        if self.shouldHandleMove:
            self.shouldHandleMove = False

            self.innerPen.moveTo(self.innerCurrentPoint)
            self.innerFirstPoint = self.innerPrevPoint = self.innerCurrentPoint

            self.outerPen.moveTo(self.outerCurrentPoint)
            self.outerFirstPoint = self.outerPrevPoint = self.outerCurrentPoint

            self.firstAngle = a1
        else:
            self.buildConnection()

        h1 = None
        if intersectPoint is not None:
            h1 = interSect((self.innerCurrentPoint, self.innerCurrentPoint + self.pointClass(cos(a1bis), sin(a1bis)) * tickness1),  (intersectPoint, p1))
        if h1 is None:
            h1 = p1 - self.pointClass(cos(a1), sin(a1)) * tickness1

        self.innerCurrentPoint = p3 - self.pointClass(cos(a2), sin(a2)) * tickness2

        h2 = None
        if intersectPoint is not None:
            h2 = interSect((self.innerCurrentPoint, self.innerCurrentPoint + self.pointClass(cos(a2bis), sin(a2bis)) * tickness2), (intersectPoint, p2))
        if h2 is None:
            h2 = p2 - self.pointClass(cos(a1), sin(a1)) * tickness1

        self.innerPen.curveTo(h1, h2, self.innerCurrentPoint)
        self.innerPrevPoint = self.innerCurrentPoint

        ########
        h1 = None
        if intersectPoint is not None:
            h1 = interSect((self.outerCurrentPoint, self.outerCurrentPoint + self.pointClass(cos(a1bis), sin(a1bis)) * tickness1), (intersectPoint, p1))
        if h1 is None:
            h1 = p1 + self.pointClass(cos(a1), sin(a1)) * tickness1

        self.outerCurrentPoint = p3 + self.pointClass(cos(a2), sin(a2)) * tickness2

        h2 = None
        if intersectPoint is not None:
            h2 = interSect((self.outerCurrentPoint, self.outerCurrentPoint + self.pointClass(cos(a2bis), sin(a2bis)) * tickness2), (intersectPoint, p2))
        if h2 is None:
            h2 = p2 + self.pointClass(cos(a1), sin(a1)) * tickness1
        self.outerPen.curveTo(h1, h2, self.outerCurrentPoint)
        self.outerPrevPoint = self.outerCurrentPoint

        self.prevPoint = p3
        self.currentAngle = a2
        self.prevAngle = a2

    def _closePath(self):
        if self.shouldHandleMove:
            return

        self.originalPen.endPath()
        self.innerPen.endPath()
        self.outerPen.endPath()

        innerContour = self.innerGlyph[-1]
        outerContour = self.outerGlyph[-1]

        innerContour.reverse()

        innerContour[0].segmentType = "line"
        outerContour[0].segmentType = "line"

        self.buildCap(outerContour, innerContour)

        for point in innerContour:
            outerContour.addPoint((point.x, point.y), segmentType=point.segmentType, smooth=point.smooth)

        self.innerGlyph.removeContour(innerContour)

    def _endPath(self):
        # The current way glyph outlines are processed means that _endPath() would not be called
        # _closePath() is used instead
        pass

    def addComponent(self, glyphName, transform):
        self.components.append((glyphName, transform))

    # thickness

    def getThickness(self, angle):
        a2 = angle + pi * .5
        f = abs(sin(a2 + radians(self.contrastAngle)))
        f = f ** 5
        return self.offset + self.contrast * f

    # connections

    def buildConnection(self, close=False):
        if not checkSmooth(self.prevAngle, self.currentAngle):
            if checkInnerOuter(self.prevAngle, self.currentAngle):
                self.connectionCallback(self.outerPrevPoint, self.outerCurrentPoint, self.outerPen, close)
                self.connectionInnerCorner(self.innerPrevPoint, self.innerCurrentPoint, self.innerPen, close)
            else:
                self.connectionCallback(self.innerPrevPoint, self.innerCurrentPoint, self.innerPen, close)
                self.connectionInnerCorner(self.outerPrevPoint, self.outerCurrentPoint, self.outerPen, close)

    def connectionRound(self, first, last, pen, close):
        angle_1 = radians(degrees(self.prevAngle)+90)
        angle_2 = radians(degrees(self.currentAngle)+90)

        tempFirst = first - self.pointClass(cos(angle_1), sin(angle_1)) * self.miterLimit
        tempLast = last + self.pointClass(cos(angle_2), sin(angle_2)) * self.miterLimit

        newPoint = interSect((first, tempFirst), (last, tempLast))
        if newPoint is None:
            pen.lineTo(last)
            return
        distance1 = newPoint.distance(first)
        distance2 = newPoint.distance(last)
        if roundFloat(distance1) > self.miterLimit + self.contrast:
            distance1 = self.miterLimit + tempFirst.distance(tempLast) * .7
        if roundFloat(distance2) > self.miterLimit + self.contrast:
            distance2 = self.miterLimit + tempFirst.distance(tempLast) * .7

        distance1 *= self.magicCurve
        distance2 *= self.magicCurve

        bcp1 = first - self.pointClass(cos(angle_1), sin(angle_1)) * distance1
        bcp2 = last + self.pointClass(cos(angle_2), sin(angle_2)) * distance2
        pen.curveTo(bcp1, bcp2, last)

    def connectionInnerCorner(self,  first, last, pen, close):
        if not close:
            pen.lineTo(last)

    # caps

    def buildCap(self, firstContour, lastContour):
        first = firstContour[-1]
        last = lastContour[0]
        first = self.pointClass(first.x, first.y)
        last = self.pointClass(last.x, last.y)

        self.capCallback(firstContour, lastContour, first, last, self.prevAngle)

        first = lastContour[-1]
        last = firstContour[0]
        first = self.pointClass(first.x, first.y)
        last = self.pointClass(last.x, last.y)

        angle = radians(degrees(self.firstAngle)+180)
        self.capCallback(lastContour, firstContour, first, last, angle)

    def capRound(self, firstContour, lastContour, first, last, angle):
        hookedAngle = radians(degrees(angle)+90)

        p1 = first - self.pointClass(cos(hookedAngle), sin(hookedAngle)) * self.offset

        p2 = last - self.pointClass(cos(hookedAngle), sin(hookedAngle)) * self.offset

        oncurve = p1 + (p2-p1)*.5

        roundness = .54

        h1 = first - self.pointClass(cos(hookedAngle), sin(hookedAngle)) * self.offset * roundness
        h2 = oncurve + self.pointClass(cos(angle), sin(angle)) * self.offset * roundness

        firstContour[-1].smooth = True

        firstContour.addPoint((h1.x, h1.y))
        firstContour.addPoint((h2.x, h2.y))
        firstContour.addPoint((oncurve.x, oncurve.y), smooth=True, segmentType="curve")

        h1 = oncurve - self.pointClass(cos(angle), sin(angle)) * self.offset * roundness
        h2 = last - self.pointClass(cos(hookedAngle), sin(hookedAngle)) * self.offset * roundness

        firstContour.addPoint((h1.x, h1.y))
        firstContour.addPoint((h2.x, h2.y))

        lastContour[0].segmentType = "curve"
        lastContour[0].smooth = True

    def drawSettings(self, drawOriginal=False, drawInner=False, drawOuter=True):
        self.drawOriginal = drawOriginal
        self.drawInner = drawInner
        self.drawOuter = drawOuter

    def drawPoints(self, pointPen):
        if self.drawInner:
            reversePen = ReverseContourPointPen(pointPen)
            self.innerGlyph.drawPoints(CleanPointPen(reversePen))
        if self.drawOuter:
            self.outerGlyph.drawPoints(CleanPointPen(pointPen))

        if self.drawOriginal:
            if self.drawOuter:
                pointPen = ReverseContourPointPen(pointPen)
            self.originalGlyph.drawPoints(CleanPointPen(pointPen))

        for glyphName, transform in self.components:
            pointPen.addComponent(glyphName, transform)

    def draw(self, pen):
        pointPen = PointToSegmentPen(pen)
        self.drawPoints(pointPen)

    def getGlyph(self):
        glyph = Glyph()
        pointPen = glyph.getPointPen()
        self.drawPoints(pointPen)
        return glyph

# The following functions have been decoupled from the outlinerRoboFontExtension and
# effectively de-parameterized, with built-in assumptions

def calculate(glyph, strokewidth):
    tickness = strokewidth
    contrast = 0
    contrastAngle = 0
    keepBounds = False
    optimizeCurve = True
    miterLimit = None  #assumed

    corner = "round"  #assumed - other options not supported
    cap = "round"  #assumed - other options not supported

    drawOriginal = False
    drawInner = True
    drawOuter = True

    pen = OutlinePen(glyph.getParent(),
                        tickness,
                        contrast,
                        contrastAngle,
                        connection=corner,
                        cap=cap,
                        miterLimit=miterLimit,
                        optimizeCurve=optimizeCurve)

    glyph.draw(pen)

    pen.drawSettings(drawOriginal=drawOriginal,
                     drawInner=drawInner,
                     drawOuter=drawOuter)

    result = pen.getGlyph()

    return result


def expandGlyph(glyph, strokewidth):
    defconGlyph = glyph
    outline = calculate(defconGlyph, strokewidth)

    glyph.clearContours()
    outline.drawPoints(glyph.getPointPen())

    glyph.round()

def expandFont(targetfont, strokewidth):
    font = targetfont
    for glyph in font:
        expandGlyph(glyph, strokewidth)

def doit(args):
    infont = OpenFont(args.ifont)
    outfont = args.ofont
    # add try to catch bad input
    strokewidth = int(args.thickness)
    expandFont(infont, strokewidth)
    infont.save(outfont)

    return infont

def cmd() : execute(None,doit,argspec)
if __name__ == "__main__": cmd()