| """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 |
| |
| |
| __all__ = ["AreaPen"] |
| |
| |
| class AreaPen(BasePen): |
| |
| def __init__(self, glyphset=None): |
| BasePen.__init__(self, glyphset) |
| self.value = 0 |
| |
| def _moveTo(self, p0): |
| self._p0 = self._startPoint = p0 |
| |
| def _lineTo(self, p1): |
| x0, y0 = self._p0 |
| x1, y1 = p1 |
| self.value -= (x1 - x0) * (y1 + y0) * .5 |
| self._p0 = p1 |
| |
| def _qCurveToOne(self, p1, p2): |
| # https://github.com/Pomax/bezierinfo/issues/44 |
| p0 = self._p0 |
| x0, y0 = p0[0], p0[1] |
| x1, y1 = p1[0] - x0, p1[1] - y0 |
| x2, y2 = p2[0] - x0, p2[1] - y0 |
| self.value -= (x2 * y1 - x1 * y2) / 3 |
| self._lineTo(p2) |
| self._p0 = p2 |
| |
| def _curveToOne(self, p1, p2, p3): |
| # https://github.com/Pomax/bezierinfo/issues/44 |
| p0 = self._p0 |
| 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 |
| self.value -= ( |
| x1 * ( - y2 - y3) + |
| x2 * (y1 - 2*y3) + |
| x3 * (y1 + 2*y2 ) |
| ) * 0.15 |
| self._lineTo(p3) |
| self._p0 = p3 |
| |
| def _closePath(self): |
| self._lineTo(self._startPoint) |
| del self._p0, self._startPoint |
| |
| def _endPath(self): |
| if self._p0 != self._startPoint: |
| # Area is not defined for open contours. |
| raise NotImplementedError |
| del self._p0, self._startPoint |
