GetECStoWCSXform() in ON6

openNURBS
1

For ON5 I had used GetECStoWCSXform() to compute the object transform for a ON_TextEntity(). In the equivalent implementation of ON_Text in ON6, what is the proper way to compute the final object transform for the text annotation? This is not something I had wanted to second guess based on what I was seeing in the Rhino UI for the text item.

2

@lowell - Can you help with this?

3

The ECStoWCS xform transforms from the annotation object’s plane to the World XY plane.
It will transform 2d points in the annotation object to world coordinates.

A function like this would still do that :

// Converts 2d points in annotation to 3d WCS points
bool GetECStoWCSXform(ON_Annotation& obj,  ON_Xform& xform ) const
{
  ON_3dVector z = ON_CrossProduct( obj.m_plane.xaxis, obj.m_plane.yaxis );
  return xform.ChangeBasis( 
          obj.m_plane.origin, obj.m_plane.xaxis, obj.m_plane.yaxis, z,
          ON_3dPoint::Origin, ON_3dVector::XAxis, ON_3dVector::YAxis, ON_3dVector::ZAxis );
}