feat(ui): ghost rendering for title block entities and text in EntityView

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

OpenNest/Controls/EntityView.cs

@@ -30,13 +30,16 @@ namespace OpenNest.Controls
         public List<Entity> OriginalEntities { get; set; }
         public bool ShowEntityLabels { get; set; }
         public List<CadText> Texts { get; set; } = new List<CadText>();
+        public HashSet<Guid> TitleBlockEntityIds { get; set; }
 
         private readonly Pen gridPen = new Pen(Color.FromArgb(70, 70, 70));
         private readonly Dictionary<int, Pen> penCache = new Dictionary<int, Pen>();
+        private readonly Dictionary<int, Pen> ghostPenCache = new Dictionary<int, Pen>();
         private readonly Font labelFont = new Font("Segoe UI", 7f);
         private readonly SolidBrush labelBrush = new SolidBrush(Color.FromArgb(220, 255, 255, 200));
         private readonly SolidBrush labelBackBrush = new SolidBrush(Color.FromArgb(33, 40, 48));
         private readonly SolidBrush textBrush = new SolidBrush(Color.FromArgb(180, 200, 200, 200));
+        private readonly SolidBrush ghostTextBrush = new SolidBrush(Color.FromArgb(50, 200, 200, 200));
 
         public event EventHandler<Line> LinePicked;
         public event EventHandler PickCancelled;
@@ -102,6 +105,13 @@ namespace OpenNest.Controls
             foreach (var entity in Entities)
             {
                 if (IsEtchLayer(entity.Layer)) continue;
+
+                if (TitleBlockEntityIds != null && TitleBlockEntityIds.Contains(entity.Id))
+                {
+                    DrawGhostEntity(e.Graphics, entity);
+                    continue;
+                }
+
                 var isHighlighted = simplifierHighlightSet != null && simplifierHighlightSet.Contains(entity);
                 var pen = isHighlighted
                     ? GetEntityPen(Color.FromArgb(60, entity.Color))
@@ -243,11 +253,26 @@ namespace OpenNest.Controls
             return pen;
         }
 
+        private Pen GetGhostPen(Color color)
+        {
+            var ghostColor = Color.FromArgb(60, color.R, color.G, color.B);
+            var argb = ghostColor.ToArgb();
+            if (!ghostPenCache.TryGetValue(argb, out var pen))
+            {
+                pen = new Pen(ghostColor);
+                ghostPenCache[argb] = pen;
+            }
+            return pen;
+        }
+
         public void ClearPenCache()
         {
             foreach (var pen in penCache.Values)
                 pen.Dispose();
             penCache.Clear();
+            foreach (var pen in ghostPenCache.Values)
+                pen.Dispose();
+            ghostPenCache.Clear();
         }
 
         private static bool IsEtchLayer(Layer layer) =>
@@ -413,10 +438,28 @@ namespace OpenNest.Controls
                 labelBrush.Dispose();
                 labelBackBrush.Dispose();
                 textBrush.Dispose();
+                ghostTextBrush.Dispose();
             }
             base.Dispose(disposing);
         }
 
+        private void DrawGhostEntity(Graphics g, Entity e)
+        {
+            var pen = GetGhostPen(e.Color);
+            switch (e.Type)
+            {
+                case EntityType.Arc:
+                    DrawArc(g, (Arc)e, pen);
+                    break;
+                case EntityType.Circle:
+                    DrawCircle(g, (Circle)e, pen);
+                    break;
+                case EntityType.Line:
+                    DrawLine(g, (Line)e, pen);
+                    break;
+            }
+        }
+
         private void DrawEntity(Graphics g, Entity e, Pen pen)
         {
             if (!e.Layer.IsVisible || !e.IsVisible)
@@ -501,8 +544,10 @@ namespace OpenNest.Controls
                 sf.Alignment = text.HAlign;
                 sf.LineAlignment = text.VAlign;
 
+                var brush = TitleBlockEntityIds != null && TitleBlockEntityIds.Count > 0
+                    ? ghostTextBrush : textBrush;
                 using var font = new Font("Segoe UI", fontSize, GraphicsUnit.Pixel);
-                g.DrawString(text.Value, font, textBrush, 0, 0, sf);
+                g.DrawString(text.Value, font, brush, 0, 0, sf);
                 g.Restore(state);
             }
         }

OpenNest/Forms/CadConverterForm.cs

@@ -162,6 +162,7 @@ namespace OpenNest.Forms
             entityView1.Entities.AddRange(item.Entities);
             entityView1.Bends = item.Bends ?? new List<Bend>();
             entityView1.Texts = item.Texts ?? new List<CadText>();
+            entityView1.TitleBlockEntityIds = item.TitleBlockEntityIds;
 
             item.Entities.ForEach(e => e.IsVisible = true);
             if (item.Entities.Any(e => e.Layer != null))