DrawableOverrule to highlight entities in nested block references and Xrefs

By Balaji Ramamoorthy

Some time back, I had posted this blog post to change the color of entities using DrawableOverrule. But it did not handle entities in block references well. Here is a completely rewritten code snippet that handles entities in block references, nested block references and Xrefs.

public class MyDrawOverrule : DrawableOverrule
{
    private bool mRegistered = false;
 
    private static bool mOldOverruleValue;
    public List _containerIds = new List();
    public ObjectId _selectedId = ObjectId.Null;
 
    public List ContainerIds
    {
        get { return _containerIds; }
        set { _containerIds = value; }
    }
 
    public ObjectId SelectedId
    {
        get { return _selectedId; }
        set { _selectedId = value; }
    }
 
    public void Highlight()
    {
        if (!mRegistered)
        {
            Overrule.AddOverrule(RXObject.GetClass
                                (typeof(Entity)), this, false);
            SetCustomFilter();
            mOldOverruleValue = Overrule.Overruling;
            mRegistered = true;
        }
        Overrule.Overruling = true;
 
        Application.DocumentManager.MdiActiveDocument
                                              .Editor.Regen();
    }
 
    public override bool WorldDraw(    Drawable drawable, 
                                    WorldDraw wd)
    {
        bool status = false;
 
        Entity ent = drawable as Entity;
 
        if(ContainerIds.Count == 0)
        {
            if(ent.ObjectId.Equals(_selectedId))
            { 
                // Not a nested entity, but selected 
                // for overruling
 
                short oldColor = wd.SubEntityTraits.Color;
                wd.SubEntityTraits.Color = 2;
 
                status = base.WorldDraw(drawable, wd);
 
                wd.SubEntityTraits.Color = oldColor;
            }
            else
                status = base.WorldDraw(drawable, wd);
        }
        else if (ContainerIds.Contains(ent.ObjectId))
        { // Selected a nested entity
 
            status = base.WorldDraw(drawable, wd);
 
            ColorizeNested(ent, Matrix3d.Identity, wd);
        }
        else
        {
            status = base.WorldDraw(drawable, wd);
        }
 
        return status;
    }
 
    public bool ColorizeNested(    Entity ent, 
                                Matrix3d transform, 
                                WorldDraw wd)
    {
        bool status = false;
        if (ent is BlockReference 
            && ContainerIds.Contains(ent.ObjectId))
        {
            BlockReference br = ent as BlockReference;
            transform 
                = transform.PreMultiplyBy(br.BlockTransform);
 
            if (br.Database != null)
            {
                using (Transaction tr 
                    = br.Database.TransactionManager
                                .StartOpenCloseTransaction())
                {
                    BlockTableRecord btr 
                        = tr.GetObject(    br.BlockTableRecord, 
                                        OpenMode.ForRead
                                      ) as BlockTableRecord;
                    foreach (ObjectId id in btr)
                    {
                        Entity btrEnt = tr.GetObject
                            (
                                id, 
                                OpenMode.ForRead
                            ) as Entity;
                        if (btrEnt is BlockReference)
                        {
                            status = ColorizeNested(
                                    btrEnt, transform, wd);
                        }
                        else
                        {
                            if (btrEnt.ObjectId.Equals(
                                                _selectedId))
                            {
                                using (Entity entClone 
                                    = btrEnt.Clone() as Entity)
                                {
                                    entClone.TransformBy
                                                  (transform);
                                    entClone.ColorIndex = 2;
                                    status 
                                    = wd.Geometry.Draw(entClone);
                                }
                            }
                        }
                    }
                    tr.Commit();
                }
            }
        }
        return status;
    }
 
    public override bool IsApplicable(RXObject overruledSubject)
    {
        bool isApplicable = false;
        Entity ent = overruledSubject as Entity;
        if (ent != null)
        {
            if (ContainerIds.Count == 0)
            {
                if(ent.ObjectId.Equals(SelectedId))
                {
                    isApplicable = true;
                }
            }
            else if (ent.ObjectId.Equals(ContainerIds[0]))
            {
                isApplicable = true;
            }
        }
        return isApplicable;
    }
}
 
public class Commands : IExtensionApplication
{
    private static MyDrawOverrule _myDrawOverrule 
                                       = new MyDrawOverrule();
 
    [CommandMethod("HighlightEnt")]
    static public void HighlightEnt()
    {
        Document doc 
              = Application.DocumentManager.MdiActiveDocument;
        Database db = doc.Database;
        Editor ed = doc.Editor;
 
        _myDrawOverrule.SelectedId = ObjectId.Null;
        _myDrawOverrule.ContainerIds.Clear();
        ObjectId selId = ObjectId.Null;
 
        PromptNestedEntityOptions pneo 
            = new PromptNestedEntityOptions(
                           "nSelect entity to highlight : ");
        PromptNestedEntityResult pner = ed.GetNestedEntity(pneo);
        if (pner.Status == PromptStatus.OK)
        {
            selId = pner.ObjectId;
            _myDrawOverrule.SelectedId = selId;
 
            List objIds 
                   = new List(pner.GetContainers());
            if (objIds.Count > 0)
            {
                objIds.Reverse();
                foreach (ObjectId id in objIds)
                    _myDrawOverrule.ContainerIds.Add(id);
            }
 
            _myDrawOverrule.Highlight();
        }
    }
 
    void IExtensionApplication.Initialize(){}
 
    void IExtensionApplication.Terminate(){}
}