Adding PR RobinPerris#52

DarkTreeView rendering optimization from Quobi:patch-2

DarkUI/Controls/DarkTreeView.cs

@@ -1268,10 +1268,29 @@ private void DrawNode(DarkTreeNode node, Graphics g)
             }
 
             // 5. Draw child nodes
-            if (node.Expanded)
-            {
-                foreach (var childNode in node.Nodes)
-                    DrawNode(childNode, g);
+            DrawChildNodes(node, g);
+        }
+
+        /// <summary>
+        /// Recursively paints only the nodes and child nodes within the viewport.
+        /// </summary>
+        private void DrawChildNodes(DarkTreeNode node, Graphics g) {
+            if( node.Expanded ) {
+                foreach( var childNode in node.Nodes ) {
+
+                    if( childNode.Expanded )
+                        DrawChildNodes(childNode, g);
+
+                    bool isInTopView = Viewport.Top <= childNode.FullArea.Y;
+                    bool isWithin = childNode.FullArea.Y < Viewport.Top + Viewport.Height;
+                    bool isPastBottomView = childNode.FullArea.Y > Viewport.Top + Viewport.Height;
+
+                    if( isInTopView && isWithin )
+                        DrawNode(childNode, g);
+
+                    if( isPastBottomView )
+                        break;
+                }
             }
         }
 

SOURCES.md

@@ -15,4 +15,6 @@ These PRs came from RobinPerris' Repo
 3. #41 https://github.com/RobinPerris/DarkUI/pull/41
    - Fixed the display of the selected item in the combobox when changing its visibility from ricardodalarme:FixedComboBox
 4. #48 https://github.com/RobinPerris/DarkUI/pull/48
-   - Fix Issue #47 from cronoxyd:master
+   - Fix Issue #47 from cronoxyd:master
+5. #52 https://github.com/RobinPerris/DarkUI/pull/52
+   - DarkTreeView rendering optimization from Quobi:patch-2