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Fixed subtle bug in curve intersection logic: due to floating point errors,

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sometimes a legitimate solution is ever so slightly over 1.0. Those used to
be filtered out; now checking for 1.0 + 1e-10.


git-svn-id: svn://svn.code.sf.net/p/fonttools/code/trunk@460 4cde692c-a291-49d1-8350-778aa11640f8
This commit is contained in:
jvr 2003-10-14 20:30:07 +00:00
parent 8e1d75b1a3
commit 05e2541b49
1 changed files with 8 additions and 2 deletions
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10
Lib/fontTools/pens/pointInsidePen.py
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@ -9,6 +9,12 @@ from fontTools.misc.bezierTools import solveQuadratic, solveCubic
__all__ = ["PointInsidePen"] __all__ = ["PointInsidePen"]
# working around floating point errors
EPSILON = 1e-10
ONE_PLUS_EPSILON = 1 + EPSILON
ZERO_MINUS_EPSILON = 0 - EPSILON
class PointInsidePen(BasePen): class PointInsidePen(BasePen):
"""This pen implements "point inside" testing: to test whether """This pen implements "point inside" testing: to test whether
@ -116,7 +122,7 @@ class PointInsidePen(BasePen):
ay = y4 - dy - cy - by ay = y4 - dy - cy - by
solutions = solveCubic(ay, by, cy, dy - y) solutions = solveCubic(ay, by, cy, dy - y)
solutions.sort() solutions.sort()
solutions = [t for t in solutions if 0 <= t <= 1] solutions = [t for t in solutions if ZERO_MINUS_EPSILON <= t <= ONE_PLUS_EPSILON]
if not solutions: if not solutions:
return return
@ -172,7 +178,7 @@ class PointInsidePen(BasePen):
a = y3 - c - b a = y3 - c - b
solutions = solveQuadratic(a, b, c - y) solutions = solveQuadratic(a, b, c - y)
solutions.sort() solutions.sort()
solutions = [t for t in solutions if 0 <= t <= 1] solutions = [t for t in solutions if ZERO_MINUS_EPSILON <= t <= ONE_PLUS_EPSILON]
if not solutions: if not solutions:
return return
XXX XXX