62 lines
1.4 KiB
Python
62 lines
1.4 KiB
Python
"""Calculate the area of a glyph."""
|
|
|
|
from __future__ import print_function, division, absolute_import
|
|
from fontTools.misc.py23 import *
|
|
from fontTools.pens.basePen import BasePen
|
|
|
|
|
|
def interpolate(p0, p1, t):
|
|
return (p0[0] * (1 - t) + p1[0] * t, p0[1] * (1 - t) + p1[1] * t)
|
|
|
|
|
|
def polygon_area(p0, p1):
|
|
return -(p1[0] - p0[0]) * (p1[1] + p0[1]) * 0.5
|
|
|
|
|
|
def quadratic_curve_area(p0, p1, p2):
|
|
x0, y0 = p0[0], p0[1]
|
|
x1, y1 = p1[0] - x0, p1[1] - y0
|
|
x2, y2 = p2[0] - x0, p2[1] - y0
|
|
return (x1*y2 - x2*y1) / 3
|
|
|
|
|
|
def cubic_curve_area(p0, p1, p2, p3):
|
|
x0, y0 = p0[0], p0[1]
|
|
x1, y1 = p1[0] - x0, p1[1] - y0
|
|
x2, y2 = p2[0] - x0, p2[1] - y0
|
|
x3, y3 = p3[0] - x0, p3[1] - y0
|
|
return -(
|
|
x1 * ( - y2 - y3) +
|
|
x2 * (y1 - 2*y3) +
|
|
x3 * (y1 + 2*y2 )
|
|
) * 0.15
|
|
|
|
|
|
class AreaPen(BasePen):
|
|
|
|
def __init__(self, glyphset=None):
|
|
BasePen.__init__(self, glyphset)
|
|
self.value = 0
|
|
|
|
def _moveTo(self, p0):
|
|
self.__startPoint = p0
|
|
|
|
def _lineTo(self, p1):
|
|
p0 = self._getCurrentPoint()
|
|
self.value += polygon_area(p0, p1)
|
|
|
|
def _curveToOne(self, p1, p2, p3):
|
|
p0 = self._getCurrentPoint()
|
|
self.value += cubic_curve_area(p0, p1, p2, p3)
|
|
self.value += polygon_area(p0, p3)
|
|
|
|
def _qCurveToOne(self, p1, p2):
|
|
p0 = self._getCurrentPoint()
|
|
self.value += quadratic_curve_area(p0, p1, p2)
|
|
self.value += polygon_area(p0, p2)
|
|
|
|
def _closePath(self):
|
|
p0 = self._getCurrentPoint()
|
|
if p0 != self.__startPoint:
|
|
self._lineTo(self.__startPoint)
|