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#!/usr/bin/env python
# coding=utf-8
#
# Copyright (C) 2005 Aaron Spike, aaron@ekips.org
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
"""
Perspective approach & math by Dmitry Platonov, shadowjack@mail.ru, 2006
"""
import inkex
from inkex.localization import inkex_gettext as _
X, Y = range(2)
try:
import numpy as np
import numpy.linalg as lin
FLOAT = np.float64
except ImportError:
np = None
class Perspective(inkex.EffectExtension):
"""Apply a perspective to a path/group of paths"""
def effect(self):
if np is None:
raise inkex.AbortExtension(
_(
"Failed to import the numpy or numpy.linalg modules. "
"These modules are required by this extension. Please install them."
" On a Debian-like system this can be done with the command, "
"sudo apt-get install python-numpy."
)
)
if len(self.svg.selection) != 2:
raise inkex.AbortExtension(
_("This extension requires two selected objects.")
)
obj, envelope = self.svg.selection
if isinstance(obj, (inkex.PathElement, inkex.Group)):
if isinstance(envelope, inkex.PathElement):
path = envelope.path.transform(
envelope.composed_transform()
).to_superpath()
if len(path) < 1 or len(path[0]) < 4:
raise inkex.AbortExtension(
_(
"This extension requires that the second path be four "
"nodes long."
)
)
dip = np.zeros((4, 2), dtype=FLOAT)
for i in range(4):
dip[i][0] = path[0][i][1][0]
dip[i][1] = path[0][i][1][1]
# Get bounding box plus any extra composed transform of parents.
bbox = obj.bounding_box(obj.getparent().composed_transform())
sip = np.array(
[
[bbox.left, bbox.bottom],
[bbox.left, bbox.top],
[bbox.right, bbox.top],
[bbox.right, bbox.bottom],
],
dtype=FLOAT,
)
else:
if isinstance(envelope, inkex.Group):
raise inkex.AbortExtension(
_(
"The second selected object is a group, not a"
" path.\nTry using Object->Ungroup."
)
)
raise inkex.AbortExtension(
_(
"The second selected object is not a path.\nTry using"
" the procedure Path->Object to Path."
)
)
else:
raise inkex.AbortExtension(
_(
"The first selected object is neither a path nor a group.\nTry "
"using the procedure Path->Object to Path."
)
)
solmatrix = np.zeros((8, 8), dtype=FLOAT)
free_term = np.zeros(8, dtype=FLOAT)
for i in (0, 1, 2, 3):
solmatrix[i][0] = sip[i][0]
solmatrix[i][1] = sip[i][1]
solmatrix[i][2] = 1
solmatrix[i][6] = -dip[i][0] * sip[i][0]
solmatrix[i][7] = -dip[i][0] * sip[i][1]
solmatrix[i + 4][3] = sip[i][0]
solmatrix[i + 4][4] = sip[i][1]
solmatrix[i + 4][5] = 1
solmatrix[i + 4][6] = -dip[i][1] * sip[i][0]
solmatrix[i + 4][7] = -dip[i][1] * sip[i][1]
free_term[i] = dip[i][0]
free_term[i + 4] = dip[i][1]
res = lin.solve(solmatrix, free_term)
projmatrix = np.array(
[[res[0], res[1], res[2]], [res[3], res[4], res[5]], [res[6], res[7], 1.0]],
dtype=FLOAT,
)
self.process_object(obj, projmatrix)
def process_object(self, obj, matrix):
if isinstance(obj, inkex.PathElement):
self.process_path(obj, matrix)
elif isinstance(obj, inkex.Group):
self.process_group(obj, matrix)
def process_group(self, group, matrix):
"""Go through all groups to process all paths inside them"""
for node in group:
self.process_object(node, matrix)
def process_path(self, element, matrix):
"""Apply the transformation to the selected path"""
point = (
element.path.to_absolute()
.transform(element.composed_transform())
.to_superpath()
)
for subs in point:
for csp in subs:
csp[0] = self.project_point(csp[0], matrix)
csp[1] = self.project_point(csp[1], matrix)
csp[2] = self.project_point(csp[2], matrix)
element.path = inkex.Path(point).transform(-element.composed_transform())
@staticmethod
def project_point(point, matrix):
"""Apply the matrix to the given point"""
return [
(point[X] * matrix[0][0] + point[Y] * matrix[0][1] + matrix[0][2])
/ (point[X] * matrix[2][0] + point[Y] * matrix[2][1] + matrix[2][2]),
(point[X] * matrix[1][0] + point[Y] * matrix[1][1] + matrix[1][2])
/ (point[X] * matrix[2][0] + point[Y] * matrix[2][1] + matrix[2][2]),
]
if __name__ == "__main__":
Perspective().run()
|
