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from robofab.world import RFont
from fontTools.pens.basePen import BasePen
from robofab.misc.arrayTools import updateBounds, pointInRect, unionRect
from robofab.misc.bezierTools import calcCubicBounds, calcQuadraticBounds
from robofab.pens.filterPen import _estimateCubicCurveLength, _getCubicPoint
import math
__all__ = ["AngledMarginPen", "getAngledMargins",
"setAngledLeftMargin", "setAngledRightMargin",
"centerAngledMargins"]
class AngledMarginPen(BasePen):
"""
Angled Margin Pen
Pen to calculate the margins as if the margin lines were slanted
according to the font.info.italicAngle.
Notes:
- this pen works on the on-curve points, and approximates the distance to curves.
- results will be float.
- when used in FontLab, the resulting margins may be slightly
different from the values originally set, due to rounding errors.
- similar to what RoboFog used to do.
- RoboFog had a special attribute for "italicoffset", horizontal
shift of all glyphs. This is missing in Robofab.
"""
def __init__(self, glyphSet, width, italicAngle):
BasePen.__init__(self, glyphSet)
self.width = width
self._angle = math.radians(90+italicAngle)
self.maxSteps = 100
self.margin = None
self._left = None
self._right = None
self._start = None
self.currentPt = None
def _getAngled(self, pt):
r = (g.width + (pt[1] / math.tan(self._angle)))-pt[0]
l = pt[0]-((pt[1] / math.tan(self._angle)))
if self._right is None:
self._right = r
else:
self._right = min(self._right, r)
if self._left is None:
self._left = l
else:
self._left = min(self._left, l)
#print pt, l, r
self.margin = self._left, self._right
def _moveTo(self, pt):
self._start = self.currentPt = pt
def _addMoveTo(self):
if self._start is None:
return
self._start = self.currentPt = None
def _lineTo(self, pt):
self._addMoveTo()
self._getAngled(pt)
def _curveToOne(self, pt1, pt2, pt3):
step = 1.0/self.maxSteps
factors = range(0, self.maxSteps+1)
for i in factors:
pt = _getCubicPoint(i*step, self.currentPt, pt1, pt2, pt3)
self._getAngled(pt)
self.currentPt = pt3
def _qCurveToOne(self, bcp, pt):
self._addMoveTo()
# add curve tracing magic here.
self._getAngled(pt)
self.currentPt = pt3
def getAngledMargins(glyph, font):
"""Get the angled margins for this glyph."""
pen = AngledMarginPen(font, glyph.width, font.info.italicAngle)
glyph.draw(pen)
return pen.margin
def setAngledLeftMargin(glyph, font, value):
"""Set the left angled margin to value, adjusted for font.info.italicAngle."""
pen = AngledMarginPen(font, glyph.width, font.info.italicAngle)
g.draw(pen)
isLeft, isRight = pen.margin
glyph.leftMargin += value-isLeft
def setAngledRightMargin(glyph, font, value):
"""Set the right angled margin to value, adjusted for font.info.italicAngle."""
pen = AngledMarginPen(font, glyph.width, font.info.italicAngle)
g.draw(pen)
isLeft, isRight = pen.margin
glyph.rightMargin += value-isRight
def centerAngledMargins(glyph, font):
"""Center the glyph on angled margins."""
pen = AngledMarginPen(font, glyph.width, font.info.italicAngle)
g.draw(pen)
isLeft, isRight = pen.margin
setAngledLeftMargin(glyph, font, (isLeft+isRight)*.5)
setAngledRightMargin(glyph, font, (isLeft+isRight)*.5)
def guessItalicOffset(glyph, font):
"""Guess the italic offset based on the margins of a symetric glyph.
For instance H or I.
"""
l, r = getAngledMargins(glyph, font)
return l - (l+r)*.5
if __name__ == "__main__":
# example for FontLab, with a glyph open.
from robofab.world import CurrentFont, CurrentGlyph
g = CurrentGlyph()
f = CurrentFont()
print "margins!", getAngledMargins(g, f)
# set the angled margin to a value
m = 50
setAngledLeftMargin(g, f, m)
setAngledRightMargin(g, f, m)
g.update()
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