dxfImportObjects.py

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"""This module provides wrapper objects for dxf entities.
    
    The wrappers expect a "dxf object" as input.  The dxf object is
    an object with a type and a data attribute.  Type is a lowercase 
    string matching the 0 code of a dxf entity.  Data is a list containing
    dxf objects or lists of [code, data] pairs.
    
    This module is not general, and is only for dxf import.
"""

# --------------------------------------------------------------------------
# DXF Import Objects v0.8 by Ed Blake (AKA Kitsu)
# --------------------------------------------------------------------------
# ***** BEGIN GPL LICENSE BLOCK *****
#
# 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
#
# ***** END GPL LICENCE BLOCK *****
# --------------------------------------------------------------------------
from math import *


# from Stani's dxf writer v1.1 (c)www.stani.be (GPL)
#---color values
BYBLOCK=0
BYLAYER=256

#---block-type flags (bit coded values, may be combined): 
ANONYMOUS               =1  # This is an anonymous block generated by hatching, associative dimensioning, other internal operations, or an application
NON_CONSTANT_ATTRIBUTES =2  # This block has non-constant attribute definitions (this bit is not set if the block has any attribute definitions that are constant, or has no attribute definitions at all)
XREF                    =4  # This block is an external reference (xref)
XREF_OVERLAY            =8  # This block is an xref overlay 
EXTERNAL                =16 # This block is externally dependent
RESOLVED                =32 # This is a resolved external reference, or dependent of an external reference (ignored on input)
REFERENCED              =64 # This definition is a referenced external reference (ignored on input)

#---mtext flags
#attachment point
TOP_LEFT        = 1
TOP_CENTER      = 2
TOP_RIGHT       = 3
MIDDLE_LEFT     = 4
MIDDLE_CENTER   = 5
MIDDLE_RIGHT    = 6
BOTTOM_LEFT     = 7
BOTTOM_CENTER   = 8
BOTTOM_RIGHT    = 9
#drawing direction
LEFT_RIGHT      = 1
TOP_BOTTOM      = 3
BY_STYLE        = 5 #the flow direction is inherited from the associated text style
#line spacing style (optional): 
AT_LEAST        = 1 #taller characters will override
EXACT           = 2 #taller characters will not override

#---polyline flags
CLOSED                      =1      # This is a closed polyline (or a polygon mesh closed in the M direction)
CURVE_FIT                   =2      # Curve-fit vertices have been added
SPLINE_FIT                  =4      # Spline-fit vertices have been added
POLYLINE_3D                 =8      # This is a 3D polyline
POLYGON_MESH                =16     # This is a 3D polygon mesh
CLOSED_N                    =32     # The polygon mesh is closed in the N direction
POLYFACE_MESH               =64     # The polyline is a polyface mesh
CONTINOUS_LINETYPE_PATTERN  =128    # The linetype pattern is generated continuously around the vertices of this polyline

#---text flags
#horizontal
LEFT        = 0
CENTER      = 1
RIGHT       = 2
ALIGNED     = 3 #if vertical alignment = 0
MIDDLE      = 4 #if vertical alignment = 0
FIT         = 5 #if vertical alignment = 0
#vertical
BASELINE    = 0
BOTTOM      = 1
MIDDLE      = 2
TOP         = 3
class Object:
    """Empty container class for dxf objects"""
    
    def __init__(self, _type=''):
        """_type expects a string value."""
        self.type = _type
        self.name = ''
        self.data = []
    
    def __str__(self):
        if self.name:
            return self.name
        else:
            return self.type
    
    def __repr__(self):
        return str(self.data)
    
    def get_type(self, kind=''):
        """Despite the name, this method actually returns all objects of type 'kind' from self.data."""
        if type:
            objects = []
            for item in self.data:
                if type(item) != list and item.type == kind:
                    # we want this type of object
                    objects.append(item)
                elif type(item) == list and item[0] == kind:
                    # we want this type of data
                    objects.append(item[1])
            return objects
    

class Layer:
    """Class for objects representing dxf layers."""
    
    def __init__(self, obj):
        """Expects an entity object of type line as input."""
        self.type = obj.type
        self.data = obj.data[:]
        
        self.name = obj.get_type(2)[0]
        self.color = obj.get_type(62)[0]
        self.flags = obj.get_type(70)[0]
        self.frozen = self.flags&1
        
    
    
    def __repr__(self):
        return "%s: name - %s, color - %s" %(self.__class__.__name__, self.name, self.color)
    


class Line:
    """Class for objects representing dxf lines."""
    
    def __init__(self, obj):
        """Expects an entity object of type line as input."""
        if not obj.type == 'line':
            raise TypeError, "Wrong type %s for line object!" %obj.type
        self.type = obj.type
        self.data = obj.data[:]
        
        self.space = obj.get_type(67)
        if self.space:
            self.space = self.space[0]
        else:
            self.space = 0
        
        self.color_index = obj.get_type(62)
        if self.color_index:
            self.color_index = self.color_index[0]
        else:
            self.color_index = BYLAYER
        
        discard, self.layer, discard_index = get_layer(obj.data)
        del obj.data[discard_index]
        
        self.points = self.get_points(obj.data)
    
    
    
    
    def get_points(self, data):
        """Gets start and end points for a line type object.
        
        Lines have a fixed number of points (two) and fixed codes for each value.
        """
        
        # start x, y, z and end x, y, z = 0
        sx, sy, sz, ex, ey, ez = 0, 0, 0, 0, 0, 0
        for item in data:
            if item[0] == 10:   # 10 = x
                sx = item[1]
            elif item[0] == 20: # 20 = y
                sy = item[1]
            elif item[0] == 30: # 30 = z
                sz = item[1]
            elif item[0] == 11: # 11 = x
                ex = item[1]
            elif item[0] == 21: # 21 = y
                ey = item[1]
            elif item[0] == 31: # 31 = z
                ez = item[1]
        return [[sx, sy, sz], [ex, ey, ez]]
    
    
    
    def __repr__(self):
        return "%s: layer - %s, points - %s" %(self.__class__.__name__, self.layer, self.points)
    


class LWpolyline:
    """Class for objects representing dxf LWpolylines."""
    
    def __init__(self, obj):
        """Expects an entity object of type lwpolyline as input."""
        if not obj.type == 'lwpolyline':
            raise TypeError, "Wrong type %s for polyline object!" %obj.type
        self.type = obj.type
        self.data = obj.data[:]
        
        # required data
        self.num_points = obj.get_type(90)[0]
        
        # optional data (with defaults)
        self.space = obj.get_type(67)
        if self.space:
            self.space = self.space[0]
        else:
            self.space = 0
            
        self.color_index = obj.get_type(62)
        if self.color_index:
            self.color_index = self.color_index[0]
        else:
            self.color_index = BYLAYER
            
        self.elevation = obj.get_type(38)
        if self.elevation:
            self.elevation = self.elevation[0]
        else:
            self.elevation = 0
            
        self.flags = obj.get_type(70)
        if self.flags:
            self.flags = self.flags[0]
        else:
            self.flags = 0
        
        self.closed = self.flags&1 # byte coded, 1 = closed, 128 = plinegen
        discard, self.layer, discard_index = get_layer(obj.data)
        del obj.data[discard_index]
        self.points = self.get_points(obj.data)
        self.extrusion = self.get_extrusion(obj.data)
    
    
    
    
    
    
    def get_points(self, data):
        """Gets points for a polyline type object.
        
        Polylines have no fixed number of verts, and 
        each vert can have a number of properties.
        Verts should be coded as 
        10:xvalue
        20:yvalue
        40:startwidth or 0
        41:endwidth or 0
        42:bulge or 0
        for each vert
        """
        num = self.num_points
        point = None
        points = []
        for item in data:
            if item[0] == 10:   # 10 = x
                if point:
                    points.append(point)
                point = Vertex()
                point.x = item[1]
            elif item[0] == 20: # 20 = y
                point.y = item[1]
            elif item[0] == 40: # 40 = start width
                point.swidth = item[1]
            elif item[0] == 41: # 41 = end width
                point.ewidth = item[1]
            elif item[0] == 42: # 42 = bulge
                point.bulge = item[1]
        points.append(point)
        return points
    
    
    def get_extrusion(self, data):
        """Find the axis of extrusion.
        
        Used to get the objects Object Coordinate System (ocs).
        """
        vec = [0,0,1]
        for item in data:
            if item[0] == 210:   # 210 = x
                vec[0] = item[1]
            elif item[0] == 220: # 220 = y
                vec[1] = item[1]
            elif item[0] == 230: # 230 = z
                vec[2] = item[1]
        return vec
    
    
    def __repr__(self):
        return "%s: layer - %s, points - %s" %(self.__class__.__name__, self.layer, self.points)
    


class Polyline:
    """Class for objects representing dxf LWpolylines."""
    
    def __init__(self, obj):
        """Expects an entity object of type polyline as input."""
        if not obj.type == 'polyline':
            raise TypeError, "Wrong type %s for polyline object!" %obj.type
        self.type = obj.type
        self.data = obj.data[:]
        self.points = []
        
        # optional data (with defaults)
        self.space = obj.get_type(67)
        if self.space:
            self.space = self.space[0]
        else:
            self.space = 0
            
        self.color_index = obj.get_type(62)
        if self.color_index:
            self.color_index = self.color_index[0]
        else:
            self.color_index = BYLAYER
            
        self.elevation = obj.get_type(30)
        if self.elevation:
            self.elevation = self.elevation[0]
        else:
            self.elevation = 0
            
        self.flags = obj.get_type(70)
        if self.flags:
            self.flags = self.flags[0]
        else:
            self.flags = 0
        
        self.closed = self.flags&1 # byte coded, 1 = closed, 128 = plinegen
            
        discard, self.layer, discard_index = get_layer(obj.data)
        del obj.data[discard_index]
        self.extrusion = self.get_extrusion(obj.data)
    
    
    
    
    
    def get_extrusion(self, data):
        """Find the axis of extrusion.
        
        Used to get the objects Object Coordinate System (ocs).
        """
        vec = [0,0,1]
        for item in data:
            if item[0] == 210:   # 210 = x
                vec[0] = item[1]
            elif item[0] == 220: # 220 = y
                vec[1] = item[1]
            elif item[0] == 230: # 230 = z
                vec[2] = item[1]
        return vec
    
    
    def __repr__(self):
        return "%s: layer - %s, points - %s" %(self.__class__.__name__, self.layer, self.points)
    


class Vertex(object):
    """Generic vertex object used by polylines (and maybe others)."""
    
    def __init__(self, obj=None):
        """Initializes vertex data.
        
            The optional obj arg is an entity object of type vertex.
        """
        self.loc = [0,0,0]
        self.bulge = 0
        self.swidth = 0
        self.ewidth = 0
        self.flags = 0
        
        if obj is not None:
            if not obj.type == 'vertex':
                raise TypeError, "Wrong type %s for vertex object!" %obj.type
            self.type = obj.type
            self.data = obj.data[:]
            
            self.get_props(obj.data)
    
    
    def get_props(self, data):
        """Gets coords for a vertex type object.
        
        Each vert can have a number of properties.
        Verts should be coded as 
        10:xvalue
        20:yvalue
        40:startwidth or 0
        41:endwidth or 0
        42:bulge or 0
        """
        for item in data:
            if item[0] == 10:   # 10 = x
                self.x = item[1]
            elif item[0] == 20: # 20 = y
                self.y = item[1]
            elif item[0] == 30: # 30 = z
                self.z = item[1]
            elif item[0] == 40: # 40 = start width
                self.swidth = item[1]
            elif item[0] == 41: # 41 = end width
                self.ewidth = item[1]
            elif item[0] == 42: # 42 = bulge
                self.bulge = item[1]
            elif item[0] == 70: # 70 = vert flags
                self.flags = item[1]
    
    
    def __len__(self):
        return 3
    
    
    def __getitem__(self, key):
        return self.loc[key]
    
    
    def __setitem__(self, key, value):
        if key in [0,1,2]:
            self.loc[key]
    
    
    def __iter__(self):
        return self.loc.__iter__()
    
    
    def __str__(self):
        return str(self.loc)
    
    
    def __repr__(self):
        return "Vertex %s, swidth=%s, ewidth=%s, bulge=%s" %(self.loc, self.swidth, self.ewidth, self.bulge)
    
    
    def getx(self):
        return self.loc[0]
    
    def setx(self, value):
        self.loc[0] = value
    
    x = property(getx, setx)
    
    
    def gety(self):
        return self.loc[1]
    
    def sety(self, value):
        self.loc[1] = value
    
    y = property(gety, sety)
    
    
    def getz(self):
        return self.loc[2]
    
    def setz(self, value):
        self.loc[2] = value
    
    z = property(getz, setz)
    


class Text:
    """Class for objects representing dxf Text."""
    
    def __init__(self, obj):
        """Expects an entity object of type text as input."""
        if not obj.type == 'text':
            raise TypeError, "Wrong type %s for text object!" %obj.type
        self.type = obj.type
        self.data = obj.data[:]
        
        # required data
        self.height = obj.get_type(40)[0]
        self.value = obj.get_type(1)[0] # The text string value
        
        # optional data (with defaults)
        self.space = obj.get_type(67)
        if self.space:
            self.space = self.space[0]
        else:
            self.space = 0
            
        self.color_index = obj.get_type(62)
        if self.color_index:
            self.color_index = self.color_index[0]
        else:
            self.color_index = BYLAYER
            
        self.rotation = obj.get_type(50) # radians?
        if not self.rotation:
            self.rotation = 0
        else:
            self.rotation = self.rotation[0]
        
        self.width_factor = obj.get_type(41) # Scaling factor along local x axis
        if not self.width_factor:
            self.width_factor = 1
        else:
            self.width_factor = self.width_factor[0]
        
        self.oblique = obj.get_type(51) # skew in degrees -90 <= oblique <= 90
        if not self.oblique:
            self.oblique = 0
        else:
            self.oblique = self.oblique[0]
        
        self.halignment = obj.get_type(72) # horiz. alignment
        if not self.halignment:  # 0=left, 1=center, 2=right, 3=aligned, 4=middle, 5=fit
            self.halignment = 0
        else:
            self.halignment = self.halignment[0]
            
        self.valignment = obj.get_type(73) # vert. alignment
        if not self.valignment:  # 0=baseline, 1=bottom, 2=middle, 3=top
            self.valignment = 0
        else:
            self.valignment = self.valignment[0]
            
        discard, self.layer, discard_index = get_layer(obj.data)
        del obj.data[discard_index]
        self.loc = self.get_loc(obj.data, self.halignment, self.valignment)
        self.extrusion = self.get_extrusion(obj.data)
    
    
    
    
    def get_loc(self, data, halign, valign):
        """Gets adjusted location for text type objects.
        
        If group 72 and/or 73 values are nonzero then the first alignment point values
        are ignored and AutoCAD calculates new values based on the second alignment
        point and the length and height of the text string itself (after applying the
        text style). If the 72 and 73 values are zero or missing, then the second
        alignment point is meaningless.
        
        I don't know how to calc text size...
        """
        # bottom left x, y, z and justification x, y, z = 0
        x, y, z, jx, jy, jz = 0, 0, 0, 0, 0, 0
        for item in data:
            if item[0] == 10:   # 10 = x
                x = item[1]
            elif item[0] == 20: # 20 = y
                y = item[1]
            elif item[0] == 30: # 30 = z
                z = item[1]
            elif item[0] == 11: # 11 = x
                jx = item[1]
            elif item[0] == 21: # 21 = y
                jy = item[1]
            elif item[0] == 31: # 31 = z
                jz = item[1]
                
        if halign or valign:
            x, y, z = jx, jy, jz
        return [x, y, z]
    
    def get_extrusion(self, data):
        """Find the axis of extrusion.
        
        Used to get the objects Object Coordinate System (ocs).
        """
        vec = [0,0,1]
        for item in data:
            if item[0] == 210:   # 210 = x
                vec[0] = item[1]
            elif item[0] == 220: # 220 = y
                vec[1] = item[1]
            elif item[0] == 230: # 230 = z
                vec[2] = item[1]
        return vec
    
    
    def __repr__(self):
        return "%s: layer - %s, value - %s" %(self.__class__.__name__, self.layer, self.value)
    


class Mtext:
    """Class for objects representing dxf Mtext."""
    
    def __init__(self, obj):
        """Expects an entity object of type mtext as input."""
        if not obj.type == 'mtext':
            raise TypeError, "Wrong type %s for mtext object!" %obj.type
        self.type = obj.type
        self.data = obj.data[:]
        
        # required data
        self.height = obj.get_type(40)[0]
        self.width = obj.get_type(41)[0]
        self.alignment = obj.get_type(71)[0] # alignment 1=TL, 2=TC, 3=TR, 4=ML, 5=MC, 6=MR, 7=BL, 8=BC, 9=BR
        self.value = self.get_text(obj.data) # The text string value
        
        # optional data (with defaults)
        self.space = obj.get_type(67)
        if self.space:
            self.space = self.space[0]
        else:
            self.space = 0
            
        self.color_index = obj.get_type(62)
        if self.color_index:
            self.color_index = self.color_index[0]
        else:
            self.color_index = BYLAYER
            
        self.rotation = obj.get_type(50) # radians
        if not self.rotation:
            self.rotation = 0
        else:
            self.rotation = self.rotation[0]
        
        self.width_factor = obj.get_type(42) # Scaling factor along local x axis
        if not self.width_factor:
            self.width_factor = 1
        else:
            self.width_factor = self.width_factor[0]
        
        self.line_space = obj.get_type(44) # percentage of default
        if not self.line_space:
            self.line_space = 1
        else:
            self.line_space = self.line_space[0]
            
        discard, self.layer, discard_index = get_layer(obj.data)
        del obj.data[discard_index]
        self.loc = self.get_loc(obj.data)
        self.extrusion = self.get_extrusion(obj.data)
    
    
    
    
    
    def get_text(self, data):
        """Reconstructs mtext data from dxf codes."""
        primary = ''
        secondary = []
        for item in data:
            if item[0] == 1: # There should be only one primary...
                primary = item[1]
            elif item[0] == 3: # There may be any number of extra strings (in order)
                secondary.append(item[1])
        if not primary:
            #raise ValueError, "Empty Mtext Object!"
            string = "Empty Mtext Object!"
        if not secondary:
            string = primary.replace(r'\P', '\n')
        else:
            string = ''.join(secondary)+primary
            string = string.replace(r'\P', '\n')
        return string    
    def get_loc(self, data):
        """Gets location for a mtext type objects.
        
        Mtext objects have only one point indicating location.
        """
        loc = [0,0,0]
        for item in data:
            if item[0] == 10:   # 10 = x
                loc[0] = item[1]
            elif item[0] == 20: # 20 = y
                loc[1] = item[1]
            elif item[0] == 30: # 30 = z
                loc[2] = item[1]
        return loc
    
    
    
    
    def get_extrusion(self, data):
        """Find the axis of extrusion.
        
        Used to get the objects Object Coordinate System (ocs).
        """
        vec = [0,0,1]
        for item in data:
            if item[0] == 210:   # 210 = x
                vec[0] = item[1]
            elif item[0] == 220: # 220 = y
                vec[1] = item[1]
            elif item[0] == 230: # 230 = z
                vec[2] = item[1]
        return vec
    
    
    def __repr__(self):
        return "%s: layer - %s, value - %s" %(self.__class__.__name__, self.layer, self.value)
    


class Circle:
    """Class for objects representing dxf Circles."""
    
    def __init__(self, obj):
        """Expects an entity object of type circle as input."""
        if not obj.type == 'circle':
            raise TypeError, "Wrong type %s for circle object!" %obj.type
        self.type = obj.type
        self.data = obj.data[:]
        
        # required data
        self.radius = obj.get_type(40)[0]
        
        # optional data (with defaults)
        self.space = obj.get_type(67)
        if self.space:
            self.space = self.space[0]
        else:
            self.space = 0
            
        self.color_index = obj.get_type(62)
        if self.color_index:
            self.color_index = self.color_index[0]
        else:
            self.color_index = BYLAYER
            
        discard, self.layer, discard_index = get_layer(obj.data)
        del obj.data[discard_index]
        self.loc = self.get_loc(obj.data)
        self.extrusion = self.get_extrusion(obj.data)
    
    
    
    
    
    def get_loc(self, data):
        """Gets the center location for circle type objects.
        
        Circles have a single coord location.
        """
        loc = [0, 0, 0]
        for item in data:
            if item[0] == 10:   # 10 = x
                loc[0] = item[1]
            elif item[0] == 20: # 20 = y
                loc[1] = item[1]
            elif item[0] == 30: # 30 = z
                loc[2] = item[1]
        return loc
    
    
    
    def get_extrusion(self, data):
        """Find the axis of extrusion.
        
        Used to get the objects Object Coordinate System (ocs).
        """
        vec = [0,0,1]
        for item in data:
            if item[0] == 210:   # 210 = x
                vec[0] = item[1]
            elif item[0] == 220: # 220 = y
                vec[1] = item[1]
            elif item[0] == 230: # 230 = z
                vec[2] = item[1]
        return vec
    
    
    def __repr__(self):
        return "%s: layer - %s, radius - %s" %(self.__class__.__name__, self.layer, self.radius)
    


class Arc:
    """Class for objects representing dxf arcs."""
    
    def __init__(self, obj):
        """Expects an entity object of type arc as input."""
        if not obj.type == 'arc':
            raise TypeError, "Wrong type %s for arc object!" %obj.type
        self.type = obj.type
        self.data = obj.data[:]
        
        # required data
        self.radius = obj.get_type(40)[0]
        self.start_angle = obj.get_type(50)[0]
        self.end_angle = obj.get_type(51)[0]
        
        # optional data (with defaults)
        self.space = obj.get_type(67)
        if self.space:
            self.space = self.space[0]
        else:
            self.space = 0
            
        self.color_index = obj.get_type(62)
        if self.color_index:
            self.color_index = self.color_index[0]
        else:
            self.color_index = BYLAYER
            
        discard, self.layer, discard_index = get_layer(obj.data)
        del obj.data[discard_index]
        self.loc = self.get_loc(obj.data)
        self.extrusion = self.get_extrusion(obj.data)
    
    
    
    
    
    def get_loc(self, data):
        """Gets the center location for arc type objects.
        
        Arcs have a single coord location.
        """
        loc = [0, 0, 0]
        for item in data:
            if item[0] == 10:   # 10 = x
                loc[0] = item[1]
            elif item[0] == 20: # 20 = y
                loc[1] = item[1]
            elif item[0] == 30: # 30 = z
                loc[2] = item[1]
        return loc
    
    
    
    def get_extrusion(self, data):
        """Find the axis of extrusion.
        
        Used to get the objects Object Coordinate System (ocs).
        """
        vec = [0,0,1]
        for item in data:
            if item[0] == 210:   # 210 = x
                vec[0] = item[1]
            elif item[0] == 220: # 220 = y
                vec[1] = item[1]
            elif item[0] == 230: # 230 = z
                vec[2] = item[1]
        return vec
    
    
    def __repr__(self):
        return "%s: layer - %s, radius - %s" %(self.__class__.__name__, self.layer, self.radius)
    


class BlockRecord:
    """Class for objects representing dxf block_records."""
    
    def __init__(self, obj):
        """Expects an entity object of type block_record as input."""
        if not obj.type == 'block_record':
            raise TypeError, "Wrong type %s for block_record object!" %obj.type
        self.type = obj.type
        self.data = obj.data[:]
        
        # required data
        self.name = obj.get_type(2)[0]
        
        # optional data (with defaults)
        self.insertion_units = obj.get_type(70)
        if not self.insertion_units:
            self.insertion_units = None
        else:
            self.insertion_units = self.insertion_units[0]
            
        self.insert_units = obj.get_type(1070)
        if not self.insert_units:
            self.insert_units = None
        else:
            self.insert_units = self.insert_units[0]
        
    
    
    
    
    
    def __repr__(self):
        return "%s: name - %s, insert units - %s" %(self.__class__.__name__, self.name, self.insertion_units)
    



class Block:
    """Class for objects representing dxf blocks."""
    
    def __init__(self, obj):
        """Expects an entity object of type block as input."""
        if not obj.type == 'block':
            raise TypeError, "Wrong type %s for block object!" %obj.type
        self.type = obj.type
        self.data = obj.data[:]
        
        # required data
        self.flags = obj.get_type(70)[0]
        self.entities = Object('block_contents')
        self.entities.data = objectify([ent for ent in obj.data if type(ent) != list])
        
        # optional data (with defaults)
        self.name = obj.get_type(3)
        if self.name:
            self.name = self.name[0]
        else:
            self.name = obj.get_type(2)
            if self.name:
                self.name = self.name[0]
            else:
                self.name = 'blank'
            
        self.path = obj.get_type(1)
        if self.path:
            self.path = self.path[0]
        else:
            self.path = ''
            
        self.discription = obj.get_type(4)
        if self.discription:
            self.discription = self.discription[0]
        else:
            self.discription = ''
            
        discard, self.layer, discard_index = get_layer(obj.data)
        del obj.data[discard_index]
        self.loc = self.get_loc(obj.data)
    
    
    
    
    
    def get_loc(self, data):
        """Gets the insert point of the block."""
        loc = [0, 0, 0]
        for item in data:
            if type(item) != list:
                continue
            if item[0] == 10:   # 10 = x
                loc[0] = item[1]
            elif item[0] == 20: # 20 = y
                loc[1] = item[1]
            elif item[0] == 30: # 30 = z
                loc[2] = item[1]
        return loc
    
    
    
    def __repr__(self):
        return "%s: name - %s, description - %s, xref-path - %s" %(self.__class__.__name__, self.name, self.discription, self.path)
    



class Insert:
    """Class for objects representing dxf inserts."""
    
    def __init__(self, obj):
        """Expects an entity object of type insert as input."""
        if not obj.type == 'insert':
            raise TypeError, "Wrong type %s for insert object!" %obj.type
        self.type = obj.type
        self.data = obj.data[:]
        
        # required data
        self.block = obj.get_type(2)[0]
        
        # optional data (with defaults)
        self.rotation = obj.get_type(50)
        if self.rotation:
            self.rotation = self.rotation[0]
        else:
            self.rotation = 0
        
        self.space = obj.get_type(67)
        if self.space:
            self.space = self.space[0]
        else:
            self.space = 0
            
        self.color_index = obj.get_type(62)
        if self.color_index:
            self.color_index = self.color_index[0]
        else:
            self.color_index = BYLAYER
        
        discard, self.layer, discard_index = get_layer(obj.data)
        del obj.data[discard_index]
        self.loc = self.get_loc(obj.data)
        self.scale = self.get_scale(obj.data)
        self.rows, self.columns = self.get_array(obj.data)
        self.extrusion = self.get_extrusion(obj.data)
    
    
    
    
    
    def get_loc(self, data):
        """Gets the center location for circle type objects.
        
        Circles have a single coord location.
        """
        loc = [0, 0, 0]
        for item in data:
            if item[0] == 10:   # 10 = x
                loc[0] = item[1]
            elif item[0] == 20: # 20 = y
                loc[1] = item[1]
            elif item[0] == 30: # 30 = z
                loc[2] = item[1]
        return loc
    
    
    
    def get_scale(self, data):
        """Gets the x/y/z scale factor for the block.
        """
        scale = [1, 1, 1]
        for item in data:
            if item[0] == 41:   # 41 = x scale
                scale[0] = item[1]
            elif item[0] == 42: # 42 = y scale
                scale[1] = item[1]
            elif item[0] == 43: # 43 = z scale
                scale[2] = item[1]
        return scale
    
    
    
    def get_array(self, data):
        """Returns the pair (row number, row spacing), (column number, column spacing)."""
        columns = 1
        rows = 1
        cspace = 0
        rspace = 0
        for item in data:
            if item[0] == 70:   # 70 = columns
                columns = item[1]
            elif item[0] == 71: # 71 = rows
                rows = item[1]
            if item[0] == 44:   # 44 = columns
                cspace = item[1]
            elif item[0] == 45: # 45 = rows
                rspace = item[1]
        return (rows, rspace), (columns, cspace)
    
    
    
    def get_extrusion(self, data):
        """Find the axis of extrusion.
        
        Used to get the objects Object Coordinate System (ocs).
        """
        vec = [0,0,1]
        for item in data:
            if item[0] == 210:   # 210 = x
                vec[0] = item[1]
            elif item[0] == 220: # 220 = y
                vec[1] = item[1]
            elif item[0] == 230: # 230 = z
                vec[2] = item[1]
        return vec
    
    
    def __repr__(self):
        return "%s: layer - %s, block - %s" %(self.__class__.__name__, self.layer, self.block)
    



class Ellipse:
    """Class for objects representing dxf ellipses."""
    
    def __init__(self, obj):
        """Expects an entity object of type ellipse as input."""
        if not obj.type == 'ellipse':
            raise TypeError, "Wrong type %s for ellipse object!" %obj.type
        self.type = obj.type
        self.data = obj.data[:]
        
        # required data
        self.ratio = obj.get_type(40)[0]
        self.start_angle = obj.get_type(41)[0]
        self.end_angle = obj.get_type(42)[0]
        
        # optional data (with defaults)
        self.space = obj.get_type(67)
        if self.space:
            self.space = self.space[0]
        else:
            self.space = 0
            
        self.color_index = obj.get_type(62)
        if self.color_index:
            self.color_index = self.color_index[0]
        else:
            self.color_index = BYLAYER
            
        discard, self.layer, discard_index = get_layer(obj.data)
        del obj.data[discard_index]
        self.loc = self.get_loc(obj.data)
        self.major = self.get_major(obj.data)
        self.extrusion = self.get_extrusion(obj.data)
        self.radius = sqrt(self.major[0]**2 + self.major[0]**2 + self.major[0]**2)
    
    
    
    
    def get_loc(self, data):
        """Gets the center location for arc type objects.
        
        Arcs have a single coord location.
        """
        loc = [0, 0, 0]
        for item in data:
            if item[0] == 10:   # 10 = x
                loc[0] = item[1]
            elif item[0] == 20: # 20 = y
                loc[1] = item[1]
            elif item[0] == 30: # 30 = z
                loc[2] = item[1]
        return loc
    
    
    
    def get_major(self, data):
        """Gets the major axis for ellipse type objects.
        
        The ellipse major axis defines the rotation of the ellipse and its radius.
        """
        loc = [0, 0, 0]
        for item in data:
            if item[0] == 11:   # 11 = x
                loc[0] = item[1]
            elif item[0] == 21: # 21 = y
                loc[1] = item[1]
            elif item[0] == 31: # 31 = z
                loc[2] = item[1]
        return loc
    
    
    
    def get_extrusion(self, data):
        """Find the axis of extrusion.
        
        Used to get the objects Object Coordinate System (ocs).
        """
        vec = [0,0,1]
        for item in data:
            if item[0] == 210:   # 210 = x
                vec[0] = item[1]
            elif item[0] == 220: # 220 = y
                vec[1] = item[1]
            elif item[0] == 230: # 230 = z
                vec[2] = item[1]
        return vec
    
    
    def __repr__(self):
        return "%s: layer - %s, radius - %s" %(self.__class__.__name__, self.layer, self.radius)
    


class Face:
    """Class for objects representing dxf 3d faces."""
    
    def __init__(self, obj):
        """Expects an entity object of type 3dfaceplot as input."""
        if not obj.type == '3dface':
            raise TypeError, "Wrong type %s for 3dface object!" %obj.type
        self.type = obj.type
        self.data = obj.data[:]
        
        # optional data (with defaults)
        self.space = obj.get_type(67)
        if self.space:
            self.space = self.space[0]
        else:
            self.space = 0
        
        self.color_index = obj.get_type(62)
        if self.color_index:
            self.color_index = self.color_index[0]
        else:
            self.color_index = BYLAYER
        
        discard, self.layer, discard_index = get_layer(obj.data)
        del obj.data[discard_index]
        self.points = self.get_points(obj.data)
    
    
    
    
    def get_points(self, data):
        """Gets 3-4 points for a 3d face type object.
        
        Faces have three or optionally four verts.
        """
        
        a = [0, 0, 0]
        b = [0, 0, 0]
        c = [0, 0, 0]
        d = False
        for item in data:
            # ----------- a -------------
            if item[0] == 10:   # 10 = x
                a[0] = item[1]
            elif item[0] == 20: # 20 = y
                a[1] = item[1]
            elif item[0] == 30: # 30 = z
                a[2] = item[1]
            # ----------- b -------------
            elif item[0] == 11: # 11 = x
                b[0] = item[1]
            elif item[0] == 21: # 21 = y
                b[1] = item[1]
            elif item[0] == 31: # 31 = z
                b[2] = item[1]
            # ----------- c -------------
            elif item[0] == 12: # 12 = x
                c[0] = item[1]
            elif item[0] == 22: # 22 = y
                c[1] = item[1]
            elif item[0] == 32: # 32 = z
                c[2] = item[1]
            # ----------- d -------------
            elif item[0] == 13: # 13 = x
                d = [0, 0, 0]
                d[0] = item[1]
            elif item[0] == 23: # 23 = y
                d[1] = item[1]
            elif item[0] == 33: # 33 = z
                d[2] = item[1]
        out = [a,b,c]
        if d:
            out.append(d)
        return out
    
    
    def __repr__(self):
        return "%s: layer - %s, points - %s" %(self.__class__.__name__, self.layer, self.points)
    

def get_name(data):
    """Get the name of an object from its object data.
    
    Returns a pair of (data_item, name) where data_item is the list entry where the name was found
    (the data_item can be used to remove the entry from the object data).  Be sure to check 
    name not None before using the returned values!
    """
    value = None
    for i, item in enumerate(data):
        if item[0] == 2:
            value = item[1]
            break
    return item, value, i

def get_layer(data):
    """Expects object data as input.
    
    Returns (entry, layer_name, entry_index) where entry is the data item that provided the layer name.
    """
    value = None
    for i, item in enumerate(data):
        if item[0] == 8:
            value = item[1]
            break
    return item, value, i


# type to object map
type_map = {
    'line':Line,
    'lwpolyline':LWpolyline,
    'text':Text,
    'mtext':Mtext,
    'circle':Circle,
    'arc':Arc,
    'layer':Layer,
    'block_record':BlockRecord,
    'block':Block,
    'insert':Insert,
    'ellipse':Ellipse,
    '3dface':Face
}

def objectify(data):
    """Expects a section type object's data as input.
    
    Maps object data to the correct object type.
    """
    objects = [] # colector for finished objects
    known_types = type_map.keys() # so we don't have to call foo.keys() every iteration
    index = 0
    while index < len(data):
        item = data[index]
        if type(item) != list and item.type in known_types:
            # proccess the object and append the resulting object
            objects.append(type_map[item.type](item))
        elif type(item) != list and item.type == 'table':
            item.data = objectify(item.data) # tables have sub-objects
            objects.append(item)
        elif type(item) != list and item.type == 'polyline':
            pline = Polyline(item)
            while 1:
                index += 1
                item = data[index]
                if item.type == 'vertex':
                    v = Vertex(item)
                    pline.points.append(v)
                elif item.type == 'seqend':
                    break
                else:
                    print "Error: non-vertex found before seqend!"
                    index -= 1
                    break
            objects.append(pline)
        else:
            # we will just let the data pass un-harrased
            objects.append(item)
        index += 1
    return objects    
if __name__ == "__main__":
    print "No example yet!"