# Sketch - A Python-based interactive drawing program
# Copyright (C) 1997, 1998, 1999 by Bernhard Herzog
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Library General Public
# License as published by the Free Software Foundation; either
# version 2 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Library General Public License for more details.
#
# You should have received a copy of the GNU Library General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
# blend function
#
from Sketch import Trafo,SketchError,_sketch
class MismatchError(SketchError):
pass
def Blend(obj1, obj2, frac1, frac2 = None):
if frac2 is None:
frac2 = 1.0 - frac1
try:
return obj1.Blend(obj2, frac1, frac2)
except MismatchError:
pass
try:
return obj2.Blend(obj1, frac2, frac1)
except MismatchError:
pass
try:
from bezier import PolyBezier
if not isinstance(obj1,PolyBezier) and not isinstance(obj2,PolyBezier)\
and obj1.is_curve and obj2.is_curve:
paths = BlendPaths(obj1.Paths(), obj2.Paths(), frac1, frac2)
properties = Blend(obj1.Properties(), obj2.Properties(),
frac1, frac2)
return PolyBezier(paths = paths, properties = properties)
except AttributeError, value:
if str(value) != 'is_curve':
raise
return obj1.Duplicate()
def BlendTrafo(t1, t2, frac1, frac2):
return Trafo(frac1 * t1.m11 + frac2 * t2.m11,
frac1 * t1.m21 + frac2 * t2.m21,
frac1 * t1.m12 + frac2 * t2.m12,
frac1 * t1.m22 + frac2 * t2.m22,
frac1 * t1.v1 + frac2 * t2.v1,
frac1 * t1.v2 + frac2 * t2.v2)
def BlendPaths(paths1, paths2, frac1, frac2):
length = min((len(paths1), len(paths2)))
paths = [None] * length
blend_paths = _sketch.blend_paths
for i in range(length):
paths[i] = blend_paths(paths1[i], paths2[i], frac1, frac2)
return tuple(paths)
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