# Source code for fontTools.pens.perimeterPen

    # -*- coding: utf-8 -*-
    """Calculate the perimeter of a glyph."""

    from fontTools.pens.basePen import BasePen
    from fontTools.misc.bezierTools import (
        approximateQuadraticArcLengthC,
        calcQuadraticArcLengthC,
        approximateCubicArcLengthC,
        calcCubicArcLengthC,
    )
    import math

    __all__ = ["PerimeterPen"]

    def _distance(p0, p1):
        return math.hypot(p0[0] - p1[0], p0[1] - p1[1])

    class PerimeterPen(BasePen):
        def __init__(self, glyphset=None, tolerance=0.005):
            BasePen.__init__(self, glyphset)
            self.value = 0
            self.tolerance = tolerance

            # Choose which algorithm to use for quadratic and for cubic.
            # Quadrature is faster but has fixed error characteristic with no strong
            # error bound.  The cutoff points are derived empirically.
            self._addCubic = (
                self._addCubicQuadrature if tolerance >= 0.0015 else self._addCubicRecursive
            )
            self._addQuadratic = (
                self._addQuadraticQuadrature
                if tolerance >= 0.00075
                else self._addQuadraticExact
            )

        def _moveTo(self, p0):
            self.__startPoint = p0

        def _closePath(self):
            p0 = self._getCurrentPoint()
            if p0 != self.__startPoint:
                self._lineTo(self.__startPoint)

        def _lineTo(self, p1):
            p0 = self._getCurrentPoint()
            self.value += _distance(p0, p1)

        def _addQuadraticExact(self, c0, c1, c2):
            self.value += calcQuadraticArcLengthC(c0, c1, c2)

        def _addQuadraticQuadrature(self, c0, c1, c2):
            self.value += approximateQuadraticArcLengthC(c0, c1, c2)

        def _qCurveToOne(self, p1, p2):
            p0 = self._getCurrentPoint()
            self._addQuadratic(complex(*p0), complex(*p1), complex(*p2))

        def _addCubicRecursive(self, c0, c1, c2, c3):
            self.value += calcCubicArcLengthC(c0, c1, c2, c3, self.tolerance)

        def _addCubicQuadrature(self, c0, c1, c2, c3):
            self.value += approximateCubicArcLengthC(c0, c1, c2, c3)

        def _curveToOne(self, p1, p2, p3):
            p0 = self._getCurrentPoint()
            self._addCubic(complex(*p0), complex(*p1), complex(*p2), complex(*p3))