Hatch¶
The HATCH entity (DXF Reference) fills an enclosed area defined by one or more boundary paths with a hatch pattern, solid fill, or gradient fill.
All points in OCS as (x, y) tuples (Hatch.dxf.elevation
is the
zaxis value).
There are two different hatch pattern default scaling, depending on the HEADER variable $MEASUREMENT, one for ISO measurement (m, cm, mm, …) and one for imperial measurement (in, ft, yd, …).
Starting with ezdxf v0.15 the default scaling for predefined hatch pattern will be chosen according this measurement setting in the HEADER section, this replicates the behavior of BricsCAD and other CAD applications. ezdxf uses the ISO pattern definitions as a base line and scales this pattern down by factor 1/25.6 for imperial measurement usage. The pattern scaling is independent from the drawing units of the document defined by the HEADER variable $INSUNITS.
Prior to ezdxf v0.15 the default scaling was always the ISO measurement scaling, no matter which value $MEASUREMENT had.
See also
Subclass of 

DXF type 

Factory function 

Inherited DXF attributes 

Required DXF version 
DXF R2000 ( 
Boundary paths helper classes
Path manager: BoundaryPaths
Pattern and gradient helper classes
Gradien

class
ezdxf.entities.
Hatch
¶ 
dxf.
pattern_name
¶ Pattern name as string

dxf.
solid_fill
¶ 1
solid fill, better use:
Hatch.set_solid_fill()
0
pattern fill, better use:
Hatch.set_pattern_fill()

dxf.
associative
¶ 1
associative hatch
0
not associative hatch
Associations not handled by ezdxf, you have to set the handles to the associated DXF entities by yourself.

dxf.
hatch_style
¶ 0
normal
1
outer
2
ignore
(search AutoCAD help for more information)

dxf.
pattern_type
¶ 0
user
1
predefined
2
custom

dxf.
pattern_angle
¶ Actual pattern angle in degrees (float). Changing this value does not rotate the pattern, use
set_pattern_angle()
for this task.

dxf.
pattern_scale
¶ Actual pattern scaling factor (float). Changing this value does not scale the pattern use
set_pattern_scale()
for this task.

dxf.
pattern_double
¶ 1 = double pattern size else 0. (int)

dxf.
n_seed_points
¶ Count of seed points (better user:
get_seed_points()
)

paths
¶ BoundaryPaths
object.

seeds
¶ List of
(x, y)
tuples.

has_solid_fill
¶ True
if hatch has a solid fill. (read only)

has_pattern_fill
¶ True
if hatch has a pattern fill. (read only)

has_gradient_data
¶ True
if hatch has a gradient fill. A hatch with gradient fill has also a solid fill. (read only)

bgcolor
¶ Property background color as (r, g, b)tuple, rgb values in the range [0, 255] (read/write/del)
usage:
color = hatch.bgcolor # get background color as (r, g, b) tuple hatch.bgcolor = (10, 20, 30) # set background color del hatch.bgcolor # delete background color

set_pattern_definition
(lines: Sequence, factor: float = 1, angle: float = 0) → None¶ Setup hatch patten definition by a list of definition lines and a definition line is a 4tuple [angle, base_point, offset, dash_length_items], the pattern definition should be designed for scaling factor 1 and angle 0.
angle: line angle in degrees
basepoint: 2tuple (x, y)
offset: 2tuple (dx, dy)
dash_length_items: list of dash items (item > 0 is a line, item < 0 is a gap and item == 0.0 is a point)
 Parameters
lines – list of definition lines
factor – pattern scaling factor
angle – rotation angle in degrees
Changed in version 0.13: added angle argument

set_pattern_scale
(scale: float) → None¶ Set scaling of pattern definition to scale.
Starts always from the original base scaling,
set_pattern_scale(1)
reset the pattern scaling to the original appearance as defined by the pattern designer, but only if the the pattern attributedxf.pattern_scale
represents the actual scaling, it is not possible to recreate the original pattern scaling from the pattern definition itself. Parameters
scale – pattern scaling factor

set_pattern_angle
(angle: float) → None¶ Set rotation of pattern definition to angle in degrees.
Starts always from the original base rotation 0,
set_pattern_angle(0)
reset the pattern rotation to the original appearance as defined by the pattern designer, but only if the the pattern attributedxf.pattern_angle
represents the actual rotation, it is not possible to recreate the original rotation from the pattern definition itself. Parameters
angle – rotation angle in degrees

set_solid_fill
(color: int = 7, style: int = 1, rgb: RGB = None)¶ Set
Hatch
to solid fill mode and removes all gradient and pattern fill related data. Parameters
color – AutoCAD Color Index (ACI), (0 = BYBLOCK; 256 = BYLAYER)
style – hatch style (0 = normal; 1 = outer; 2 = ignore)
rgb – true color value as (r, g, b)tuple  has higher priority than color. True color support requires DXF R2000.

set_pattern_fill
(name: str, color: int = 7, angle: float = 0.0, scale: float = 1.0, double: int = 0, style: int = 1, pattern_type: int = 1, definition=None) → None¶ Set
Hatch
to pattern fill mode. Removes all gradient related data. The pattern definition should be designed for scaling factor 1. Predefined hatch pattern like “ANSI33” are scaled according to the HEADER variable $MEASUREMENT for ISO measurement (m, cm, … ), or imperial units (in, ft, …), this replicates the behavior of BricsCAD. Parameters
name – pattern name as string
color – pattern color as AutoCAD Color Index (ACI)
angle – angle of pattern fill in degrees
scale – pattern scaling as float
double – double size flag
style – hatch style (0 = normal; 1 = outer; 2 = ignore)
pattern_type – pattern type (0 = userdefined; 1 = predefined; 2 = custom)
definition – list of definition lines and a definition line is a 4tuple [angle, base_point, offset, dash_length_items], see
set_pattern_definition()

set_gradient
(color1: RGB = (0, 0, 0), color2: RGB = (255, 255, 255), rotation: float = 0.0, centered: float = 0.0, one_color: int = 0, tint: float = 0.0, name: str = 'LINEAR') → None¶ Set
Hatch
to gradient fill mode and removes all pattern fill related data. Gradient support requires DXF DXF R2004. A gradient filled hatch is also a solid filled hatch.Valid gradient type names are:
'LINEAR'
'CYLINDER'
'INVCYLINDER'
'SPHERICAL'
'INVSPHERICAL'
'HEMISPHERICAL'
'INVHEMISPHERICAL'
'CURVED'
'INVCURVED'
 Parameters
color1 – (r, g, b)tuple for first color, rgb values as int in the range [0, 255]
color2 – (r, g, b)tuple for second color, rgb values as int in the range [0, 255]
rotation – rotation angle in degrees
centered – determines whether the gradient is centered or not
one_color – 1 for gradient from color1 to tinted color1
tint – determines the tinted target color1 for a one color gradient. (valid range 0.0 to 1.0)
name – name of gradient type, default “LINEAR”

set_seed_points
(points: Iterable[Tuple[float, float]]) → None¶ Set seed points, points is an iterable of (x, y)tuples. I don’t know why there can be more than one seed point. All points in OCS (
Hatch.dxf.elevation
is the Z value)

associate
(path: Union[PolylinePath, EdgePath], entities: Iterable[DXFEntity])¶ Set association from hatch boundary path to DXF geometry entities.
A HATCH entity can be associative to a base geometry, this association is not maintained nor verified by ezdxf, so if you modify the base geometry the geometry of the boundary path is not updated and no verification is done to check if the associated geometry matches the boundary path, this opens many possibilities to create invalid DXF files: USE WITH CARE!

remove_association
()¶ Remove associated path elements.

Boundary Paths¶
The hatch entity is build by different functional path types, this are
filter flags for the Hatch.dxf.hatch_style
:
EXTERNAL: defines the outer boundary of the hatch
OUTERMOST: defines the first tier of inner hatch boundaries
DEFAULT: default boundary path
As you will learn in the next sections, these are more the recommended usage type for the flags, but the fill algorithm doesn’t care much about that, for instance an OUTERMOST path doesn’t have to be inside the EXTERNAL path.
Island Detection¶
In general the island detection algorithm works always from outside to inside
and alternates filled and unfilled areas. The area between then 1st and the 2nd
boundary is filled, the area between the 2nd and the 3rd boundary is unfilled
and so on. The different hatch styles defined by the Hatch.dxf.hatch_style
attribute are created by filtering some boundary path types.
Hatch Style¶
HATCH_STYLE_IGNORE: Ignores all paths except the paths marked as EXTERNAL, if there are more than one path marked as EXTERNAL, they are filled in NESTED style. Creates no hatch if no path is marked as EXTERNAL.
HATCH_STYLE_OUTERMOST: Ignores all paths marked as DEFAULT, remaining EXTERNAL and OUTERMOST paths are filled in NESTED style. Creates no hatch if no path is marked as EXTERNAL or OUTERMOST.
HATCH_STYLE_NESTED: Use all existing paths.
Hatch Boundary Helper Classes¶

class
ezdxf.entities.
BoundaryPaths
¶ Defines the borders of the hatch, a hatch can consist of more than one path.

paths
¶ List of all boundary paths. Contains
PolylinePath
andEdgePath
objects. (read/write)

external_paths
() → Iterable[Union[PolylinePath, EdgePath]]¶ Iterable of external paths, could be empty.

outermost_paths
() → Iterable[Union[PolylinePath, EdgePath]]¶ Iterable of outermost paths, could be empty.

default_paths
() → Iterable[Union[PolylinePath, EdgePath]]¶ Iterable of default paths, could be empty.

rendering_paths
(hatch_style: int) → Iterable[Union[PolylinePath, EdgePath]]¶ Iterable of paths to process for rendering, filters unused boundary paths according to the given hatch style:
NESTED: use all boundary paths
OUTERMOST: use EXTERNAL and OUTERMOST boundary paths
IGNORE: ignore all paths except EXTERNAL boundary paths
Yields paths in order of EXTERNAL, OUTERMOST and DEFAULT.

add_polyline_path
(path_vertices, is_closed=1, flags=1) → PolylinePath¶ Create and add a new
PolylinePath
object. Parameters
path_vertices – list of polyline vertices as (x, y) or (x, y, bulge)tuples.
is_closed – 1 for a closed polyline else 0
flags – external(1) or outermost(16) or default (0)

add_edge_path
(flags=1) → EdgePath¶ Create and add a new
EdgePath
object. Parameters
flags – external(1) or outermost(16) or default (0)

polyline_to_edge_path
(just_with_bulge=True) → None¶ Convert polyline paths including bulge values to line and arc edges.
 Parameters
just_with_bulge – convert only polyline paths including bulge values if
True

arc_edges_to_ellipse_edges
() → None¶ Convert all arc edges to ellipse edges.

ellipse_edges_to_spline_edges
(num: int = 32) → None¶ Convert all ellipse edges to spline edges (approximation).
 Parameters
num – count of control points for a full ellipse, partial ellipses have proportional fewer control points but at least 3.

spline_edges_to_line_edges
(factor: int = 8) → None¶ Convert all spline edges to line edges (approximation).
 Parameters
factor – count of approximation segments = count of control points x factor

all_to_spline_edges
(num: int = 64) → None¶ Convert all bulge, arc and ellipse edges to spline edges (approximation).
 Parameters
num – count of control points for a full circle/ellipse, partial circles/ellipses have proportional fewer control points but at least 3.

all_to_line_edges
(num: int = 64, spline_factor: int = 8) → None¶ Convert all bulge, arc and ellipse edges to spline edges and approximate this splines by line edges.
 Parameters
num – count of control points for a full circle/ellipse, partial circles/ellipses have proportional fewer control points but at least 3.
spline_factor – count of spline approximation segments = count of control points x spline_factor

clear
() → None¶ Remove all boundary paths.


class
ezdxf.entities.
PolylinePath
¶ A polyline as hatch boundary path.

path_type_flags
¶ (bit coded flags)
0
default
1
external
2
polyline, will be set by ezdxf
16
outermost
My interpretation of the
path_type_flags
, see also Tutorial for Hatch:external  path is part of the hatch outer border
outermost  path is completely inside of one or more external paths
default  path is completely inside of one or more outermost paths
If there are troubles with AutoCAD, maybe the hatch entity has the
Hatch.dxf.pixel_size
attribute set  delete itdel hatch.dxf.pixel_size
and maybe the problem is solved. ezdxf does not use theHatch.dxf.pixel_size
attribute, but it can occur in DXF files created by other applications.

is_closed
¶ True
if polyline path is closed.

vertices
¶ List of path vertices as (x, y, bulge)tuples. (read/write)

source_boundary_objects
¶ List of handles of the associated DXF entities for associative hatches. There is no support for associative hatches by ezdxf, you have to do it all by yourself. (read/write)

set_vertices
(vertices: Sequence[Sequence[float]], is_closed: bool = True) → None¶ Set new vertices as new polyline path, a vertex has to be a (x, y) or a (x, y, bulge)tuple.

clear
() → None¶ Removes all vertices and all handles to associated DXF objects (
source_boundary_objects
).


class
ezdxf.entities.
EdgePath
¶ Boundary path build by edges. There are four different edge types:
LineEdge
,ArcEdge
,EllipseEdge
ofSplineEdge
. Make sure there are no gaps between edges. AutoCAD in this regard is very picky. ezdxf performs no checks on gaps between the edges.
path_type_flags
¶ (bit coded flags)
0
default
1
external
16
outermost

edges
¶ List of boundary edges of type
LineEdge
,ArcEdge
,EllipseEdge
ofSplineEdge

source_boundary_objects
¶ Required for associative hatches, list of handles to the associated DXF entities.

clear
() → None¶ Delete all edges.

add_line
(start, end) → LineEdge¶ Add a
LineEdge
from start to end. Parameters
start – start point of line, (x, y)tuple
end – end point of line, (x, y)tuple

add_arc
(center, radius=1., start_angle=0., end_angle=360., ccw: bool = True) → ArcEdge¶ Add an
ArcEdge
. Parameters
center – center point of arc, (x, y)tuple
radius – radius of circle
start_angle – start angle of arc in degrees
end_angle – end angle of arc in degrees
ccw –
True
for counter clockwiseFalse
for clockwise orientation

add_ellipse
(center, major_axis_vector=(1., 0.), minor_axis_length=1., start_angle=0., end_angle=360., ccw: bool = True) → EllipsePath¶ Add an
EllipseEdge
. Parameters
center – center point of ellipse, (x, y)tuple
major_axis – vector of major axis as (x, y)tuple
ratio – ratio of minor axis to major axis as float
start_angle – start angle of arc in degrees
end_angle – end angle of arc in degrees
ccw –
True
for counter clockwiseFalse
for clockwise orientation

add_spline
(fit_points=None, control_points=None, knot_values=None, weights=None, degree=3, rational=0, periodic=0) → SplinePath¶ Add a
SplineEdge
. Parameters
fit_points – points through which the spline must go, at least 3 fit points are required. list of (x, y)tuples
control_points – affects the shape of the spline, mandatory and AutoCAD crashes on invalid data. list of (x, y)tuples
knot_values – (knot vector) mandatory and AutoCAD crashes on invalid data. list of floats; ezdxf provides two tool functions to calculate valid knot values:
ezdxf.math.uniform_knot_vector()
,ezdxf.math.open_uniform_knot_vector()
(default ifNone
)weights – weight of control point, not mandatory, list of floats.
degree – degree of spline (int)
periodic – 1 for periodic spline, 0 for none periodic spline
start_tangent – start_tangent as 2d vector, optional
end_tangent – end_tangent as 2d vector, optional
Warning
Unlike for the spline entity AutoCAD does not calculate the necessary knot_values for the spline edge itself. On the contrary, if the knot_values in the spline edge are missing or invalid AutoCAD crashes.


class
ezdxf.entities.
LineEdge
¶ Straight boundary edge.

start
¶ Start point as (x, y)tuple. (read/write)

end
¶ End point as (x, y)tuple. (read/write)


class
ezdxf.entities.
ArcEdge
¶ Arc as boundary edge.

center
¶ Center point of arc as (x, y)tuple. (read/write)

radius
¶ Arc radius as float. (read/write)

start_angle
¶ Arc start angle in degrees. (read/write)

end_angle
¶ Arc end angle in degrees. (read/write)

ccw
¶ True
for counter clockwise arc elseFalse
. (read/write)


class
ezdxf.entities.
EllipseEdge
¶ Elliptic arc as boundary edge.

major_axis_vector
¶ Ellipse major axis vector as (x, y)tuple. (read/write)

minor_axis_length
¶ Ellipse minor axis length as float. (read/write)

radius
¶ Ellipse radius as float. (read/write)

start_angle
¶ Ellipse start angle in degrees. (read/write)

end_angle
¶ Ellipse end angle in degrees. (read/write)

ccw
¶ True
for counter clockwise ellipse elseFalse
. (read/write)


class
ezdxf.entities.
SplineEdge
¶ Spline as boundary edge.

degree
¶ Spline degree as int. (read/write)

rational
¶ 1 for rational spline else 0. (read/write)

periodic
¶ 1 for periodic spline else 0. (read/write)

knot_values
¶ List of knot values as floats. (read/write)

control_points
¶ List of control points as (x, y)tuples. (read/write)

fit_points
¶ List of fit points as (x, y)tuples. (read/write)

weights
¶ List of weights (of control points) as floats. (read/write)

start_tangent
¶ Spline start tangent (vector) as (x, y)tuple. (read/write)

end_tangent
¶ Spline end tangent (vector) as (x, y)tuple. (read/write)

Hatch Pattern Definition Helper Classes¶

class
ezdxf.entities.
Pattern
¶ 
lines
¶ List of pattern definition lines (read/write). see
PatternLine

add_line
(angle: float = 0, base_point: Vertex = (0, 0), offset: Vertex = (0, 0), dash_length_items: Iterable[float] = None) → None¶ Create a new pattern definition line and add the line to the
Pattern.lines
attribute.

clear
() → None¶ Delete all pattern definition lines.

scale
(factor: float = 1, angle: float = 0) → None¶ Scale and rotate pattern.
Be careful, this changes the base pattern definition, maybe better use
Hatch.set_pattern_scale()
orHatch.set_pattern_angle()
. Parameters
factor – scaling factor
angle – rotation angle in degrees


class
ezdxf.entities.
PatternLine
¶ Represents a pattern definition line, use factory function
Pattern.add_line()
to create new pattern definition lines.
angle
¶ Line angle in degrees. (read/write)

base_point
¶ Base point as (x, y)tuple. (read/write)

offset
¶ Offset as (x, y)tuple. (read/write)

dash_length_items
¶ List of dash length items (item > 0 is line, < 0 is gap, 0.0 = dot). (read/write)

Hatch Gradient Fill Helper Classes¶

class
ezdxf.entities.
Gradient
¶ 
color1
¶ First rgb color as (r, g, b)tuple, rgb values in range 0 to 255. (read/write)

color2
¶ Second rgb color as (r, g, b)tuple, rgb values in range 0 to 255. (read/write)

one_color
¶ If
one_color
is 1  the hatch is filled with a smooth transition betweencolor1
and a specifiedtint
ofcolor1
. (read/write)

rotation
¶ Gradient rotation in degrees. (read/write)

centered
¶ Specifies a symmetrical gradient configuration. If this option is not selected, the gradient fill is shifted up and to the left, creating the illusion of a light source to the left of the object. (read/write)
