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[symfont] Simplify GlyphStatistics; just compute everything upfront

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Our MomentsPen is sooooooooo fast now, there's no point trying to
make it lazy.
This commit is contained in:
Behdad Esfahbod 2017-02-20 11:28:44 -06:00
parent 8712c20156
commit d9bccb8609
1 changed files with 35 additions and 60 deletions
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95
Snippets/symfont.py
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@ -202,6 +202,12 @@ class GlyphStatistics(object):
self._glyphset = glyphset
self._transform = transform
pen = transformer = PerimeterPen(glyphset=self._glyphset)
if self._transform:
transformer = TransformPen(pen, self._transform)
self._glyph.draw(transformer)
self.Perimeter = pen.value
Pen = MomentsPen
pen = transformer = Pen(glyphset=self._glyphset)
if self._transform:
@ -209,78 +215,47 @@ class GlyphStatistics(object):
self._glyph.draw(transformer)
self.m = m = pen
self.Area = m.area
self.Area = area = m.area
self.Moment1X = m.momentX
self.Moment1Y = m.momentY
self.Moment2XX = m.momentXX
self.Moment2XY = m.momentXY
self.Moment2YY = m.momentYY
def _penAttr(self, attr):
internalName = '_'+attr
if internalName not in self.__dict__:
Pen = globals()[attr+'Pen']
pen = transformer = Pen(glyphset=self._glyphset)
if self._transform:
transformer = TransformPen(pen, self._transform)
self._glyph.draw(transformer)
self.__dict__[internalName] = pen.value
return self.__dict__[internalName]
if not area:
self.MeanX = 0.
self.MeanY = 0.
self.VarianceX = 0.
self.VarianceY = 0.
self.StdDevX = 0.
self.StdDevY = 0.
self.Covariance = 0.
self.Correlation = 0.
self.Slant = 0.
return
#Area = property(partial(_penAttr, attr='Area'))
Perimeter = property(partial(_penAttr, attr='Perimeter'))
#Moment1X = property(partial(_penAttr, attr='Moment1X'))
#Moment1Y = property(partial(_penAttr, attr='Moment1Y'))
#Moment2XX = property(partial(_penAttr, attr='Moment2XX'))
#Moment2YY = property(partial(_penAttr, attr='Moment2YY'))
#Moment2XY = property(partial(_penAttr, attr='Moment2XY'))
# Center of mass
# https://en.wikipedia.org/wiki/Center_of_mass#A_continuous_volume
self.MeanX = self.Moment1X / area
self.MeanY = self.Moment1Y / area
# TODO Memoize properties below
# Var(X) = E[X^2] - E[X]^2
self.VarianceX = self.Moment2XX / area - self.MeanX**2
self.VarianceY = self.Moment2YY / area - self.MeanY**2
# Center of mass
# https://en.wikipedia.org/wiki/Center_of_mass#A_continuous_volume
@property
def MeanX(self):
return self.Moment1X / self.Area if self.Area else 0
@property
def MeanY(self):
return self.Moment1Y / self.Area if self.Area else 0
self.StdDevX = math.copysign(abs(self.VarianceX)**.5, self.VarianceX)
self.StdDevY = math.copysign(abs(self.VarianceY)**.5, self.VarianceY)
# https://en.wikipedia.org/wiki/Second_moment_of_area
# Covariance(X,Y) = ( E[X.Y] - E[X]E[Y] )
self.Covariance = self.Moment2XY / area - self.MeanX*self.MeanY
# Var(X) = E[X^2] - E[X]^2
@property
def VarianceX(self):
return self.Moment2XX / self.Area - self.MeanX**2 if self.Area else 0
@property
def VarianceY(self):
return self.Moment2YY / self.Area - self.MeanY**2 if self.Area else 0
@property
def StdDevX(self):
return math.copysign(abs(self.VarianceX)**.5, self.VarianceX)
@property
def StdDevY(self):
return math.copysign(abs(self.VarianceY)**.5, self.VarianceY)
# Correlation(X,Y) = Covariance(X,Y) / ( StdDev(X) * StdDev(Y)) )
# https://en.wikipedia.org/wiki/Pearson_product-moment_correlation_coefficient
corr = self.Covariance / (self.StdDevX * self.StdDevY)
self.Correlation = corr if abs(corr) > 1e-3 else 0
# Covariance(X,Y) = ( E[X.Y] - E[X]E[Y] )
@property
def Covariance(self):
return self.Moment2XY / self.Area - self.MeanX*self.MeanY if self.Area else 0
# Correlation(X,Y) = Covariance(X,Y) / ( StdDev(X) * StdDev(Y)) )
# https://en.wikipedia.org/wiki/Pearson_product-moment_correlation_coefficient
@property
def Correlation(self):
corr = self.Covariance / (self.StdDevX * self.StdDevY) if self.Area else 0
if abs(corr) < 1e-3: corr = 0
return corr
@property
def Slant(self):
slant = self.Covariance / self.VarianceY if self.VarianceY else 0
if abs(slant) < 1e-3: slant = 0
return slant
slant = self.Covariance / self.VarianceY
self.Slant = slant if abs(slant) > 1e-3 else 0
def test(glyphset, upem, glyphs):