# Sketch - A Python-based interactive drawing program
# Copyright (C) 1997, 1998, 1999, 2000, 2001 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
from Sketch import CreatePath,Rotation,Translation,Scale
from Sketch._sketch import ContAngle,ContSmooth,ContSymmetrical,Bezier,Line
def arrow_vectors(path, arrow1, arrow2):
# Return the directions for the arrow heads of path as a pair of
# point objects. If the path is closed or consists of only one Node,
# return (None, None).
dir1 = dir2 = None
if not path.closed and path.len > 1:
if arrow1:
type, controls, p3, cont = path.Segment(1)
p = path.Node(0)
if type == Bezier:
p1, p2 = controls
dir = p - p1
if not abs(dir):
dir = p - p2
else:
dir = p - p3
dir1 = dir
if arrow2:
type, controls, p, cont = path.Segment(-1)
p3 = path.Node(-2)
if type == Bezier:
p1, p2 = controls
dir = p - p2
if not abs(dir):
dir = p - p1
else:
dir = p - p3
dir2 = dir
return dir1, dir2
def arrow_trafos(path, properties):
dir1, dir2 = arrow_vectors(path, properties.line_arrow1,
properties.line_arrow2)
width = properties.line_width
if width < 1.0:
width = 1.0
scale = Scale(width)
t1 = t2 = None
if dir1 is not None:
t1 = Translation(path.Node(0))(Rotation(dir1.polar()[1]))(scale)
if dir2 is not None:
t2 = Translation(path.Node(-1))(Rotation(dir2.polar()[1]))(scale)
return t1, t2
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