Source code for plugins.dxf

##  This file is part of pyFormex 1.0.7  (Mon Jun 17 12:20:39 CEST 2019)
##  pyFormex is a tool for generating, manipulating and transforming 3D
##  geometrical models by sequences of mathematical operations.
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##  Copyright 2004-2019 (C) Benedict Verhegghe (
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"""Read/write geometry in DXF format.

This module allows to import and export some simple geometrical items
in DXF format.
from __future__ import absolute_import, division, print_function

from pyformex.formex import *
from pyformex.plugins import curve
from pyformex import utils

# Avoid compilation problems
def execSource(s, g):
    exec(s, g)

[docs]def importDXF(filename): """Import (parts of) a DXF file into pyFormex. This function scans a DXF file for recognized entities and imports those entities as pyFormex objects. It is only a very partial importer, but has proven to be already very valuable for many users. `filename`: name of a DXF file. The return value is a list of pyFormex objects. Importing a DXF file is done in two steps: - First the DXF file is scanned and the recognized entities are formatted into a text with standard function calling syntax. See :func:`readDXF`. - Then the created text is executed as a Python script, producing equivalent pyFormex objects. See :func:`convertDXF`. """ text = readDXF(filename) if text: return convertDXF(text) else: return []
[docs]def readDXF(filename): """Read a DXF file and extract the recognized entities. `filename`: name of a .DXF file. Returns a multiline string with one line for each recognized entity, in a format that can directly be used by :func:`convertDXF`. This function requires the external program `dxfparser` which comes with the pyFormex distribution. It currently recognizes entities of type 'Arc', 'Line', 'Polyline', 'Vertex'. """ print(filename) if utils.hasExternal('dxfparser'): cmd = 'pyformex-dxfparser %s 2>/dev/null' % filename print(cmd) P = utils.command(cmd, shell=True) if P.sta==0: return P.out else: return '' else: utils.warn('warn_dxf_noparser') return ''
Entities = [] Vertices = []
[docs]def convertDXF(text): """Convert a textual representation of a DXF format to pyFormex objects. `text` : a multiline text representation of the contents of a DXF file. This text representation can e.g. be obtained by the function :func:`readDXF`. It contains lines defining DXF entities. A small example:: Arc(0.0,0.0,0.0,1.0,-90.,90.) Arc(0.0,0.0,0.0,3.0,-90.,90.) Line(0.0,-1.0,0.0,0.0,1.0,0.0) Polyline(0) Vertex(0.0,3.0,0.0) Vertex(-2.0,3.0,0.0) Vertex(-2.0,-7.0,0.0) Vertex(0.0,-7.0,0.0) Vertex(0.0,-3.0,0.0) Each line of the text defines a single entity or starts a multiple component entity. The text should be well aligned to constitute a proper Python script. Currently, the only defined entities are 'Arc', 'Line', 'Polyline', 'Vertex'. Returns a list of pyFormex objects corresponding to the text. The returned objects are of the following type: ============= ================================ function name object ============= ================================ Arc :class:`plugins.curve.Arc` Line :class:`plugins.curve.Line` Polyline :class:`plugins.curve.PolyLine` ============= ================================ No object is returned for the `Vertex` function: they define the vertices of a PolyLine. """ import types global Entities, Vertices Entities = [] Vertices = [] # Simple type (Line, Arc) create the object and append it to the # Entities list # Compound types (like Polyline) append the corresponding # EndEntity function to the Entities list def EndEntity(): global Entities, Vertices if Entities: f = Entities[-1] if isinstance(f, types.FunctionType): f() def Arc(x0, y0, z0, r, a0, a1): global Entities, Vertices count = len(Entities) part = curve.Arc(center=[x0, y0, z0], radius=r, angles=[a0, a1]).setProp(count) part.dxftype = 'Arc' Entities.append(part) def Circle(x0, y0, z0, r): Arc(x0, y0, z0, r, 0., 360.) def Line(x0, y0, z0, x1, y1, z1): global Entities, Vertices count = len(Entities) part = curve.Line([[x0, y0, z0], [x1, y1, z1]]).setProp(count) part.dxftype = 'Line' Entities.append(part) def Polyline(n): global Entities, Vertices EndEntity() Entities.append(EndPolyline) Vertices = [] def EndPolyline(): global Entities, Vertices count = len(Entities) - 1 part = curve.PolyLine(Vertices).setProp(count) part.dxftype = 'Polyline' Entities[-1] = part Vertices = [] def Vertex(x, y, z): global Entities, Vertices Vertices.append([x, y, z]) l = {'Line': Line, 'Arc': Arc, 'Circle': Circle, 'Polyline': Polyline, 'EndPolyline': EndPolyline, 'Vertex': Vertex} execSource(text, l) EndEntity() return Entities
[docs]def collectByType(entities): """Collect the dxf entities by type.""" coll = {} types = {type(i) for i in entities} print("DXF collection:") for t in types: n = t.__name__ cn = [i for i in entities if isinstance(i, t)] print(" items of type %s: %s" % (n, len(cn))) coll[n] = cn return coll
[docs]def toLines(coll, chordal=0.01, arcdiv=None): """Convert the dxf entities in a dxf collection to a plex-2 Formex This converts Lines, Arcs and PolyLines to plex-2 elements and collects them in a single Formex. The chordal and arcdiv parameters are passed to :meth:`Arc.approx` to set the accuracy for the approximation of the Arc by line segments. """ Lines = [] for k, v in coll.items(): if k in ['Line', 'PolyLine']: Lines.extend([a.toFormex() for a in v]) elif k == 'Arc': Lines.extend([a.toFormex(chordal=chordal, ndiv=arcdiv) for a in v]) return Formex.concatenate(Lines)
[docs]class DxfExporter(object): """Export geometry in DXF format. While we certainly do not want to promote proprietary software, some of our users occasionally needed to export some model in DXF format. This class provides a minimum of functionality. """ def __init__(self, filename, terminator='\n'): """Open a file for export in DXF format. No check is done that the file has a '.dxf' extension. The file will by default be written in UNIX line termination mode. An existing file will be overwritten without warning! """ self.filename = filename self.fil = open(self.filename, 'w') self.term = terminator
[docs] def write(self, s): """Write a string to the dxf file. The string does not include the line terminator. """ self.fil.write(s+self.term)
[docs] def out(self, code, data): """Output a string data item to the dxf file. code is the group code, data holds the data """ self.write('%3s' % code) self.write('%s' % data)
[docs] def close(self): """Finalize and close the DXF file""" self.out(0, 'EOF') self.fil.close()
[docs] def section(self, name): """Start a new section""" self.out(0, 'SECTION') self.out(2, name)
[docs] def endSection(self): """End the current section""" self.out(0, 'ENDSEC')
[docs] def entities(self): """Start the ENTITIES section""" self.section('ENTITIES')
[docs] def layer(self, layer): """Export the layer""" self.out(8, layer)
[docs] def vertex(self, x, layer=0): """Export a vertex. x is a (3,) shaped array """ self.out(0, 'VERTEX') self.out(8, layer) for i in range(3): self.out(10*(i+1), x[i])
[docs] def line(self, x, layer=0): """Export a line. x is a (2,3) shaped array """ self.out(0, 'LINE') self.out(8, layer) for j in range(2): for i in range(3): self.out(10*(i+1)+j, x[j][i])
[docs] def polyline(self, x, layer=0): """Export a polyline. x is a (nvertices,3) shaped array """ self.out(0, 'POLYLINE') self.out(8, layer) for xi in x: self.vertex(xi, layer) self.out(0, 'SEQEND')
[docs] def arc(self, C, R, a, layer=0): """Export an arc. """ self.out(0, 'ARC') self.out(8, layer) for k, v in [ (10, C[0]), (20, C[1]), (30, C[2]), (40, R), (50, a[0]), (51, a[1]), ]: self.out(k, v)
[docs]def exportDXF(filename, F): """Export a Formex to a DXF file Currently, only plex-2 Formices can be exported to DXF. """ if F.nplex() != 2: raise ValueError("Can only export plex-2 Formices to DXF") dxf = DxfExporter(filename) dxf.entities() for i in F: dxf.line(i) dxf.endSection() dxf.close()
[docs]def exportDxf(filename, coll): """Export a collection of dxf parts a DXF file coll is a list of dxf objects Currently, only dxf objects of type 'Line' and 'Arc' can be exported. """ dxf = DxfExporter(filename) dxf.entities() for ent in coll: print(type(ent), ent) if isinstance(ent, curve.Line): dxf.line(ent.coords) elif isinstance(ent, curve.Arc): dxf.arc(ent.getCenter(), ent.radius, ent.getAngles()) elif isinstance(ent, curve.PolyLine): dxf.polyline(ent.coords) else: utils.warn('warn_dxf_export', data=type(ent)) dxf.endSection() dxf.close()
[docs]def exportDxfText(filename, parts): """Export a set of dxf entities to a .dxftext file.""" fil = open(filename, 'w') for p in parts: fil.write(p.dxftext()+'\n') fil.close()
# An example if __name__ == '__draw__': #chdir(__file__) from pyformex.simple import circle c = circle(360./20., 360./20., 360.) draw(c) exportDXF('circle1.dxf', c) #End