Keep Text entity always parallel to screen

The following Text entity, always maintains the text parallel to the screen. It can also be useful for dimension entities to facilitate reading during dynamic rotations.

public class MyText : Text 
{ 
     public MyText(double x, double y, string textString, double height) 
                : base(x, y, textString, height) 
     { 
     } 

     // In Eyeshot 7 since there is not the Viewport parameter in the "DrawParams", we must keep a reference to the viewport. 
     // Of course it will only work for ViewportLayouts with one viewport. 
     // In Eyeshot 8 there won't be this restriction anymore 
     public Viewport viewport; 

     protected override void Draw(DrawParams data) 
     { 
         Point3D orig; 
         Vector3D xAxis, yAxis, zAxis; 
         // data.Viewport.Camera.GetFrame(out orig, out xAxis, out yAxis, out zAxis); // EYESHOT 8 

         viewport.Camera.GetFrame(out orig, out xAxis, out yAxis, out zAxis); // EYESHOT 7 

         Align3D al = new Align3D(Plane, new Plane(this.InsertionPoint, xAxis, yAxis)); 

         gl.PushMatrix(); 
         gl.MultMatrixd(al.MatrixAsVectorByColumn); 
         DrawText(data); 
         gl.PopMatrix(); 
     } 
}