Importer.py

####################################################################################################
#
# Patro - A Python library to make patterns for fashion design
# Copyright (C) 2017 Fabrice Salvaire
#
# 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 3 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, see <http://www.gnu.org/licenses/>.
#
####################################################################################################

"""Module to handle the DXF file format.

"""

####################################################################################################

__all__ = ['DxfImporter']

####################################################################################################

import ezdxf # Python packahe to read/write DXF

from Patro.GeometryEngine.Conic import Circle2D, Ellipse2D, AngularDomain
from Patro.GeometryEngine.Segment import Segment2D
from Patro.GeometryEngine.Spline import BSpline2D
from Patro.GeometryEngine.Vector import Vector2D

from .Polyline import Polyline

####################################################################################################

class DxfImporter:

    """Class to implement a DXF importer.
    """

    ##############################################

    def __init__(self, path):

        path = str(path)
        self._drawing = ezdxf.readfile(path)
        self._model_space = self._drawing.modelspace()
        self._items = []
        self._read()

    ##############################################

    def __len__(self):
        return len(self._items)

    def __iter__(self):
        return iter(self._items)

    def __getitem__(self, slice_):
        return self._items[slice_]

    ##############################################

    @staticmethod
    def _to_vector(point):
        return Vector2D(point[:2])

    @classmethod
    def _to_vectors(cls, points):
        return [cls._to_vector(x) for x in points]

    ##############################################

    def _add(self, item):
        self._items.append(item)

    ##############################################

    def _read(self):

        for item in self._model_space:
            dxf_type = item.dxftype()
            if dxf_type == 'LINE':
                self._on_line(item)
            elif dxf_type in ('CIRCLE', 'ARC'):
                self._on_circle(item, dxf_type == 'ARC')
            elif dxf_type == 'ELLIPSE':
                self._on_ellipse(item)
            elif dxf_type == 'LWPOLYLINE':
                self._on_polyline(item)
            elif dxf_type == 'SPLINE':
                self._on_spline(item)
            # else skip

    ##############################################

    def _on_line(self, item):
        item_dxf = item.dxf
        segment = Segment2D(*self._to_vectors((item_dxf.start, item_dxf.end)))
        self._add(segment)


    ##############################################

    def _on_circle(self, item, is_arc):

        item_dxf = item.dxf
        center = self._to_vector(item_dxf.center)
        if is_arc:
            domain = AngularDomain(item_dxf.start_angle, item_dxf.end_angle)
        else:
            domain = None
        circle = Circle2D(center, item_dxf.radius, domain=domain)
        self._add(circle)

    ##############################################

    def _on_ellipse(self, item):

        item_dxf = item.dxf
        center = self._to_vector(item_dxf.center)
        major_axis = self._to_vector(item_dxf.major_axis)
        minor_axis = major_axis * item_dxf.ratio
        domain = AngularDomain(item_dxf.start_param, item_dxf.end_param, degrees=False)
        radius_x, radius_y = major_axis.magnitude, minor_axis.magnitude
        angle = major_axis.orientation
        if angle == 90:
            radius_x, radius_y = radius_y, radius_x
            angle = 0
        # Fixme: ...
        ellipse = Ellipse2D(
            center,
            radius_x, radius_y,
            angle,
            domain=domain,
        )
        self._add(ellipse)

    ##############################################

    def _on_polyline(self, item):

        polyline = Polyline(item.closed)
        for x, y, s, e, b in item.get_points():
            polyline.add(Vector2D(x, y), b)
        geometry = polyline.geometry()
        self._add(geometry)

    ##############################################

    def _on_spline(self, item):

        with item.edit_data() as data:
            points = self._to_vectors(data.control_points)
        item_dxf = item.dxf
        spline = BSpline2D(points, item_dxf.degree, item.closed)
        self._add(spline)