Drawing / Export Addon

This add-on provides the functionality to render a DXF document to produce a rasterized or vector-graphic image which can be saved to a file or viewed interactively depending on the backend being used.

The module provides two example scripts in the folder examples/addons/drawing which can be run to save rendered images to files or view an interactive visualisation

Example for the usage of the matplotlib backend:

import sys
import matplotlib.pyplot as plt
from ezdxf import recover
from ezdxf.addons.drawing import RenderContext, Frontend
from ezdxf.addons.drawing.matplotlib import MatplotlibBackend

# Safe loading procedure (requires ezdxf v0.14):
    doc, auditor = recover.readfile('your.dxf')
except IOError:
    print(f'Not a DXF file or a generic I/O error.')
except ezdxf.DXFStructureError:
    print(f'Invalid or corrupted DXF file.')

# The auditor.errors attribute stores severe errors,
# which may raise exceptions when rendering.
if not auditor.has_errors:
    fig = plt.figure()
    ax = fig.add_axes([0, 0, 1, 1])
    ctx = RenderContext(doc)
    out = MatplotlibBackend(ax)
    Frontend(ctx, out).draw_layout(doc.modelspace(), finalize=True)
    fig.savefig('your.png', dpi=300)

Simplified render workflow but with less control:

from ezdxf import recover
from ezdxf.addons.drawing import matplotlib

# Exception handling left out for compactness:
doc, auditor = recover.readfile('your.dxf')
if not auditor.has_errors:
    matplotlib.qsave(doc.modelspace(), 'your.png')


class ezdxf.addons.drawing.matplotlib.MatplotlibBackend
__init__(ax: plt.Axes, *, adjust_figure: bool = True, font: FontProperties, use_text_cache: bool = True)


class ezdxf.addons.drawing.pyqt.PyQtBackend
__init__(scene: qw.QGraphicsScene = None, *, use_text_cache: bool = True, debug_draw_rect: bool = False)


Additional options for the drawing add-on can be passed by the config argument of the Frontend constructor __init__(). Not every option will be supported by all backends.

class ezdxf.addons.drawing.config.Configuration

Configuration options for the drawing add-on.


the size to draw POINT entities (in drawing units) set to None to use the $PDSIZE value from the dxf document header

0 5% of draw area height
<0 Specifies a percentage of the viewport size
>0 Specifies an absolute size
None use the $PDMODE value from the dxf document header

point styling mode (see POINT documentation)

see Point class documentation


whether to use metric or imperial units as enum ezdxf.enums.Measurement

0 use imperial units (in, ft, yd, …)
1 use metric units (ISO meters)
None use the $MEASUREMENT value from the dxf document header

whether to show or filter out POINT entities on the defpoints layer


the action to take when a proxy graphic is encountered


the method to use when drawing styled lines (eg dashed, dotted etc)


the method to use when drawing HATCH entities


the length to use when drawing infinite lines


set to 0.0 for a constant minimal width the current result is correct, in SVG the line width is 0.7 points for 0.25mm as required, but it often looks too thick


the minimum line width in 1/300 inch, set to None for let the the backend choose.


the minimum length for a dash when drawing a styled line (default value is arbitrary)


Max flattening distance in drawing units see Path.flattening documentation. The backend implementation should calculate an appropriate value, like 1 screen- or paper pixel on the output medium, but converted into drawing units. Sets Path() approximation accuracy


Approximate a full circle by n segments, arcs have proportional less segments. Only used for approximation of arcs in banded polylines.


Returns a frozen Configuration object with default values.


Returns a new frozen Configuration object with modified values.


my_config = Configuration.defaults()
my_config = my_config.with_changes(lineweight_scaling=2)


class ezdxf.addons.drawing.config.LinePolicy

draw all lines as solid regardless of the linetype style


use the closest approximation available to the backend for rendering styled lines


analyse and render styled lines as accurately as possible. This approach is slower and is not well suited to interactive applications.


class ezdxf.addons.drawing.config.HatchPolicy

The action to take when a HATCH entity is encountered


do not show HATCH entities at all


show only the outline of HATCH entities


show HATCH entities but draw with solid fill regardless of the pattern


show HATCH entities using the closest approximation available to the current backend


class ezdxf.addons.drawing.config.ProxyGraphicPolicy

The action to take when an entity with a proxy graphic is encountered


To get proxy graphics support proxy graphics have to be loaded: Set the global option ezdxf.options.load_proxy_graphics to True, which is the default value.

This can not prevent drawing proxy graphic inside of blocks, because this is outside of the domain of the drawing add-on!


do not display proxy graphics (skip_entity will be called instead)


if the entity cannot be rendered directly (eg if not implemented) but a proxy is present: display the proxy


display proxy graphics even for entities where direct rendering is available


class ezdxf.addons.drawing.properties.Properties


class ezdxf.addons.drawing.properties.LayerProperties


class ezdxf.addons.drawing.properties.RenderContext


class ezdxf.addons.drawing.frontend.Frontend


class ezdxf.addons.drawing.backend.Backend


The rendering is performed in two stages. The front-end traverses the DXF document structure, converting each encountered entity into primitive drawing commands. These commands are fed to a back-end which implements the interface: Backend.

Currently a PyQtBackend (QGraphicsScene based) and a MatplotlibBackend are implemented.

Although the resulting images will not be pixel-perfect with AutoCAD (which was taken as the ground truth when developing this add-on) great care has been taken to achieve similar behavior in some areas:

  • The algorithm for determining color should match AutoCAD. However, the color palette is not stored in the dxf file, so the chosen colors may be different to what is expected. The RenderContext class supports passing a plot style table (CTB-file) as custom color palette but uses the same palette as AutoCAD by default.
  • Text rendering is quite accurate, text positioning, alignment and word wrapping are very faithful. Differences may occur if a different font from what was used by the CAD application but even in that case, for supported backends, measurements are taken of the font being used to match text as closely as possible.
  • Visibility determination (based on which layers are visible) should match AutoCAD

See examples/addons/drawing/cad_viewer.py for an advanced use of the module.

See examples/addons/drawing/draw_cad.py for a simple use of the module.

See drawing.md in the ezdxf repository for additional behaviours documented during the development of this add-on.


  • Rich text formatting is ignored (drawn as plain text)
  • If the backend does not match the font then the exact text placement and wrapping may appear slightly different
  • MULTILEADER renders only proxy graphic if available
  • relative size of POINT entities cannot be replicated exactly
  • only basic support for:
    • infinite lines (rendered as lines with a finite length)
    • VIEWPORT and OLE2FRAME entities (rendered as rectangles)
    • 3D entities are projected into the xy-plane and 3D text is not supported
    • vertical text (will render as horizontal text)
    • multiple columns of text (placement of additional columns may be incorrect)