read_polygon_xld_dxf — Read XLD polygons from a DXF file.
read_polygon_xld_dxf reads the contents of the DXF file FileName (DXF version AC1009, AutoCAD Release 12) and converts them to the XLD polygons Polygons. If no absolute path is given in FileName the DXF file is searched in the current directory of the HALCON process.
The output parameter DxfStatus contains information about the number of polygons that were read and, if necessary, warnings that parts of the DXF file could not be interpreted.
The operator read_polygon_xld_dxf supports the following DXF entities:
2D curves made up of line segments
Closed 2D curves made up of line segments
The x and y coordinates of the DXF entities are stored in the column and row coordinates, respectively, of the XLD polygons Polygons. The z coordinates of the DXF entities are ignored.
DXF entities of the type CIRCLE, ARC, ELLIPSE, and SPLINE are approximated by XLD polygons. The accuracy of this approximation can be controlled with the two generic parameters 'min_num_points' and 'max_approx_error' (for SPLINE only 'max_approx_error'). Generic parameters are set by specifying the parameter name(s) in GenParamNames and the corresponding value(s) in GenParamValues. The parameter 'min_num_points' defines the minimum number of sampling points that are used for the approximation. Note that the parameter 'min_num_points' always refers to the full circle or ellipse, respectively, even for ARCs or elliptical arcs, i.e., if 'min_num_points' is set to 50 and a DXF entity of the type ARC is read that represents a semi-circle, this semi-circle is approximated by at least 25 sampling points. The parameter 'max_approx_error' defines the maximum deviation of the XLD polygon from the ideal circle or ellipse, respectively (unit: pixel). For the determination of the accuracy of the approximation both criteria are evaluated. Then, the criterion that leads to the more accurate approximation is used.
Internally, the following default values are used for the generic parameters:
'min_num_points' = 20
'max_approx_error' = 0.25
To achieve a more accurate approximation, either the value for 'min_num_points' must be increased or the value for 'max_approx_error' must be decreased.
Note that reading a DXF file with read_polygon_xld_dxf results in exactly the same geometric information as reading the file with read_contour_xld_dxf. However, the resulting data structure is different.
Read XLD polygons.
Name of the DXF file.
File extension: .dxf
Names of the generic parameters that can be adjusted for the DXF input.
Default value: 
List of values: 'max_approx_error', 'min_num_points'
Values of the generic parameters that can be adjusted for the DXF input.
Default value: 
Suggested values: 0.1, 0.25, 0.5, 1, 2, 5, 10, 20
If the parameters are correct and the file could be read the operator read_polygon_xld_dxf returns the value 2 (H_MSG_TRUE). Otherwise, an exception is raised.