read_contour_xld_dxf — Read XLD contours from a DXF file.
read_contour_xld_dxf( : Contours : FileName, GenParamName, GenParamValue : DxfStatus)
read_contour_xld_dxf reads the contents of the DXF file
FileName (DXF version AC1009, AutoCAD Release 12) and
converts them to the XLD contours Contours.
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 contours that were read and, if necessary,
warnings that parts of the DXF file could not be interpreted.
The operator read_contour_xld_dxf supports the following
DXF entities:
POLYLINE
2D curves made up of line segments
Closed 2D curves made up of line segments
LWPOLYLINE
LINE
POINT
CIRCLE
ARC
ELLIPSE
SPLINE
BLOCK
INSERT
The x and y coordinates of the DXF entities are stored in the column
and row coordinates, respectively, of the XLD contours
Contours. The z coordinates of the DXF entities are
ignored.
If the file has been created with the operator
write_contour_xld_dxf, all attributes and global attributes
that were originally defined for the XLD contours are read.
This means that read_contour_xld_dxf supports all the extended
data written by the operator write_contour_xld_dxf.
The reading of these attributes can be switched off by setting
the generic parameter 'read_attributes' to
'false'. Generic parameters are set by specifying the
parameter name(s) in GenParamName and the corresponding
value(s) in GenParamValue.
DXF entities of the type CIRCLE, ARC, ELLIPSE, and SPLINE are approximated by XLD contours. The accuracy of this approximation can be controlled with the two generic parameters 'min_num_points' and 'max_approx_error'. 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 contour 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:
'read_attributes' = 'true'
'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.
Contours (output_object) xld_cont(-array) → object
Read XLD contours.
FileName (input_control) filename.read → (string)
Name of the DXF file.
File extension: .dxf
GenParamName (input_control) attribute.name(-array) → (string)
Names of the generic parameters that can be adjusted for the DXF input.
Default value: []
List of values: 'max_approx_error', 'min_num_points', 'read_attributes'
GenParamValue (input_control) attribute.value(-array) → (real / integer / string)
Values of the generic parameters that can be adjusted for the DXF input.
Default value: []
Suggested values: 'true', 'false', 0.1, 0.25, 0.5, 1, 2, 5, 10, 20
DxfStatus (output_control) string(-array) → (string)
Status information.
If the parameters are correct and the file could be read the
operator read_contour_xld_dxf returns the value 2 (H_MSG_TRUE).
Otherwise, an exception is raised.
write_contour_xld_dxf,
read_polygon_xld_dxf,
query_contour_attribs_xld,
query_contour_global_attribs_xld,
get_contour_attrib_xld,
get_contour_global_attrib_xld
Foundation