I'm currently developing a CAD application using C++ and Qt, where I'm utilizing the libdxfrw library to generate DXF files. My application is focused on cloth pattern making, and it's crucial for me to support the DXF ASTM standard for exchanging data.
Recently, I've added support for mirror lines to define symmetry of pieces. However, I've encountered a challenge regarding certain parts that must not be mirrored. According to the documentation, I need to use a text attribute "NM" (Not Mirrored) at the start point and layer of the element to exclude specific internal lines from being mirrored.
Here's a quote from the documentation:
If a piece is to be mirrored, but one or more of the internal lines is to be excluded, as is the case in asymmetrical appearance, the line must carry the text attribute NM for 'Not Mirrored' at the start point and layer of the element. This is done by placing the text string NM at the XY coordinates of the first vertex of the (poly) line or point element.
I'm struggling to implement this feature correctly. I've searched for examples from other CAD applications, but I couldn't find any relevant files.
Could someone provide guidance or a working example of how to correctly implement the "NM" text attribute in the DXF ASTM standard for a C++/Qt CAD application using the libdxfrw library?
Any help or insights would be greatly appreciated. Thank you!