EdgeSmith

Added in version 1.4.

Purpose of this Module

This is a companion module to the ezdxf.edgeminer module:

create Edge instances from DXF primitives for processing by the edgeminer module:

Line

Arc

Ellipse

Spline

LWPolyline

Polyline

create LWPolyline and Polyline entities from a sequence of Edge objects.

create Hatch boundary paths from a sequence of Edge objects.

create ezdxf.path.Path objects from a sequence of Edge objects.

Make Edges

This functions convert open shapes into 2D edges, closed shapes as circles, closed arcs, closed ellipses, closed splines and closed polylines are ignored or return None.

ezdxf.edgesmith.make_edge_2d(entity: DXFEntity, *, gap_tol=GAP_TOL) → ezdxf.edgeminer.Edge | None

Makes an Edge instance from the following DXF entity types:

Line (length accurate)
Arc (length accurate)
Ellipse (length approximated)
Spline (length approximated as straight lines between control points)
LWPolyline (length of bulges as straight line from start- to end point)
Polyline (length of bulges as straight line from start- to end point)

The start- and end points of the edge is projected onto the xy-plane. Returns None if the entity has a closed shape or cannot be represented as an edge.

ezdxf.edgesmith.edges_from_entities_2d(entities: Iterable[DXFEntity], *, gap_tol=GAP_TOL) → Iterator[Edge]

Yields all DXF entities as 2D edges in the xy-plane of the WCS.

Skips all entities that have a closed shape or can not be represented as edge.

Build From Edges

ARC, LWPOLYLINE, POLYLINE and ELLIPSE entities must have an extrusion vector of (0, 0, 1) (WCS Z-Axis). Entities with an inverted extrusion vector (0, 0, -1) will be treated as a 3D curve and approximated by a polyline projected onto the xy-plane. The ezdxf.upright module can convert such inverted extrusion vectors to (0, 0, 1).

Curve Approximation

For some target entities curves have to be approximated by polylines. This process is also called flattening and is controlled by the parameter max_sagitta. (Wikipedia)

The max_sagitta argument defines the maximum distance from the center of the curve segment to the center of the line segment between two approximation points to determine if a segment should be subdivided. The default value is -1 and uses a 1/100 of the approximated length of the curve as max_sagitta.

The good choice for a max_sagitta depends on the output resolution and is maybe not known at the time of processing the data. E.g. for a printer/plotter a max_sagitta of around 1/300 inch (300 dpi) is maybe a good choice. The convertion from output units to drawing units depends on the scale and is the task of the package user.

All flattened curves will be projected onto the xy-plane of the WCS.

ezdxf.edgesmith.lwpolyline_from_chain(edges: Sequence[Edge], *, dxfattribs: Any = None, max_sagitta: float = -1) → LWPolyline

Returns a new virtual LWPolyline entity.

This function assumes the building blocks as simple DXF entities attached as payload to the edges. The edges are processed in order of the input sequence and the start- and end points of the edges should be connected. The output polyline is projected onto the xy-plane of the WCS.

Line as line segment

Arc as bulge

Ellipse as bulge or as flattened line segments

Spline as flattened line segments

LWPolyline and Polyline will be merged

Everything else will be added as line segment from Edge.start to Edge.end

Gaps between edges are connected by line segments.

ezdxf.edgesmith.polyline2d_from_chain(edges: Sequence[Edge], *, dxfattribs: Any = None, max_sagitta: float = -1) → Polyline

Returns a new virtual Polyline entity.

This function assumes the building blocks as simple DXF entities attached as payload to the edges. The edges are processed in order of the input sequence and the start- and end points of the edges should be connected. The output polyline is projected onto the xy-plane of the WCS.

Line as line segment

Arc as bulge

Ellipse as bulge or as flattened line segments

Spline as flattened line segments

LWPolyline and Polyline will be merged

Everything else will be added as line segment from Edge.start to Edge.end

Gaps between edges are connected by line segments.

ezdxf.edgesmith.edge_path_from_chain(edges: Sequence[Edge], *, max_sagitta: float = -1, flags: int = 1) → EdgePath

Returns a new EdgePath for Hatch entities.

This function assumes the building blocks as simple DXF entities attached as payload to the edges. The edges are processed in order of the input sequence and the start- and end points of the edges should be connected. The output path is projected onto the xy-plane of the WCS.

Line as LineEdge

Arc as ArcEdge

Ellipse as EllipseEdge

Spline as SplineEdge

LWPolyline and Polyline will be exploded and added as LineEdge and ArcEdge

Everything else will be added as line segment from Edge.start to Edge.end

Gaps between edges are connected by line segments.

Parameters:

edges – Sequence of Edge instances with DXF primitives attached as payload
max_sagitta (float) – curve flattening parameter
flags (int) – default(0), external(1), derived(4), textbox(8) or outermost(16)

ezdxf.edgesmith.polyline_path_from_chain(edges: Sequence[Edge], *, max_sagitta: float = -1, is_closed=True, flags: int = 1) → PolylinePath

Returns a new PolylinePath for Hatch entities.

This function assumes the building blocks as simple DXF entities attached as payload to the edges. The edges are processed in order of the input sequence and the start- and end points of the edges should be connected. The output path is projected onto the xy-plane of the WCS.

Line as line segment

Arc as bulge

Ellipse as bulge or flattened line segments

Spline as flattened line segments

LWPolyline and Polyline are merged

Everything else will be added as line segment from Edge.start to Edge.end

Gaps between edges are connected by line segments.

Parameters:

edges – Sequence of Edge instances with DXF primitives attached as payload
max_sagitta (float) – curve flattening parameter
is_closed (bool) – True if path is implicit closed
flags (int) – default(0), external(1), derived(4), textbox(8) or outermost(16)

ezdxf.edgesmith.path2d_from_chain(edges: Sequence[Edge]) → Path

Returns a new ezdxf.path.Path entity.

This function assumes the building blocks as simple DXF entities attached as payload to the edges. The edges are processed in order of the input sequence and the start- and end points of the edges should be connected. The output is a 2D path projected onto the xy-plane of the WCS.

Line as line segment

Arc as cubic Bézier curves

Ellipse as cubic Bézier curves

Spine cubic Bézier curves

LWPolyline and Polyline as line segments and cubic Bézier curves

Everything else will be added as line segment from Edge.start to Edge.end

Gaps between edges are connected by line segments.

Helper Functions

ezdxf.edgesmith.is_closed_entity(entity: DXFEntity) → bool

Returns True if the given entity represents a closed loop.

Tests the following DXF entities:

CIRCLE

ARC

ELLIPSE

SPLINE

LWPOLYLINE

POLYLINE

HATCH

SOLID

TRACE

Returns False for all other DXF entities.

ezdxf.edgesmith.is_pure_2d_entity(entity: DXFEntity) → bool

Returns True if the given entity represents a pure 2D entity in the xy-plane of the WCS.

All vertices must be in the xy-plane of the WCS.
Thickness must be 0.
The extrusion vector must be (0, 0, 1).
Entities with inverted extrusions vectors (0, 0, -1) are not pure 2D entities. The ezdxf.upright module can be used to revert inverted extrusion vectors back to (0, 0, 1).

Tests the following DXF entities:

LINE

CIRCLE

ARC

ELLIPSE

SPLINE

LWPOLYLINE

POLYLINE

HATCH

SOLID

TRACE

Returns False for all other DXF entities.

ezdxf.edgesmith.filter_edge_entities(entities: Iterable[DXFEntity]) → Iterator[DXFEntity]

Returns all entities that can be used to build edges in the context of ezdxf.edgeminer.

Returns the following DXF entities:

LINE

ARC

ELLIPSE

SPLINE

LWPOLYLINE

POLYLINE

Note

CIRCLE, TRACE and SOLID are closed shapes by definition and cannot be used as edge in the context of ezdxf.edgeminer or ezdxf.edgesmith.
This filter is not limited to pure 2D entities!
Does not test if the entity is a closed loop!

ezdxf.edgesmith.filter_2d_entities(entities: Iterable[DXFEntity]) → Iterator[DXFEntity]: Returns all pure 2D entities, ignores all entities placed outside or extending beyond the xy-plane of the WCS. See is_pure_2d_entity() for more information.

ezdxf.edgesmith.filter_open_edges(entities: Iterable[DXFEntity]) → Iterator[DXFEntity]

Returns all open linear entities usable as edges in the context of ezdxf.edgeminer or ezdxf.edgesmith.

Ignores all entities that represent closed loops like circles, closed arcs, closed ellipses, closed splines and closed polylines.

Note

This filter is not limited to pure 2D entities!

ezdxf.edgesmith.bounding_box_2d(edges: Sequence[Edge]) → BoundingBox2d: Returns the BoundingBox2d of all start- and end vertices.

ezdxf.edgesmith.loop_area(edges: Sequence[Edge], *, gap_tol=GAP_TOL) → float

Returns the area of a closed loop.

Raises:: ValueError – edges are not a closed loop

ezdxf.edgesmith.is_inside_polygon_2d(edges: Sequence[Edge], point: UVec, *, gap_tol=GAP_TOL) → bool

Returns True when point is inside the polygon.

The edges must be a closed loop. The polygon is build from edges as straight lines from start- to end vertex, independently whatever the edges really represent. A point at a boundary line is inside the polygon.

Parameters:

edges – sequence of Edge representing a closed loop
point – point to test
gap_tol – maximum vertex distance to consider two edges as connected

Raises:

ValueError – edges are not a closed loop

ezdxf.edgesmith.intersecting_edges_2d(edges: Sequence[em.Edge], p1: UVec, p2: UVec | None = None) → list[IntersectingEdge]

Returns all edges that intersect a line from point p1 to point p2.

If p2 is None an arbitrary point outside the bounding box of all start- and end vertices beyond extmax.x will be chosen. The edges are handled as straight lines from start- to end vertex, projected onto the xy-plane of the WCS. The result is sorted by the distance from intersection point to point p1.

class ezdxf.edgesmith.IntersectingEdge

NamedTuple as return type of intersecting_edges_2d().

edge: Intersecting edge as Edge; alias for field 0.

distance: Distance from intersection point to point p1 as float; alias for field 1.

Global Constants

GAP_TOL = 1e-9
LEN_TOL = 1e-9  # length and distance
DEG_TOL = 1e-9  # angles in degree
RAD_TOL = 1e-7  # angles in radians