feat: optimize selection implement by binary search

frontend/app_flowy/packages/flowy_editor/example/assets/example.json

@@ -9,12 +9,6 @@
           "image_src": "https://s1.ax1x.com/2022/07/28/vCgz1x.png"
         }
       },
-      {
-        "type": "youtube_link",
-        "attributes": {
-          "youtube_link": "https://flutter.github.io/assets-for-api-docs/assets/videos/bee.mp4"
-        }
-      },
       {
         "type": "text",
         "delta": [

frontend/app_flowy/packages/flowy_editor/example/lib/main.dart

@@ -99,6 +99,15 @@ class _MyHomePageState extends State<MyHomePage> {
             },
             icon: const Icon(Icons.text_fields),
           ),
+          ActionButton(
+            onPressed: () {
+              if (page == 3) return;
+              setState(() {
+                page = 3;
+              });
+            },
+            icon: const Icon(Icons.email),
+          ),
         ],
       ),
     );
@@ -111,6 +120,8 @@ class _MyHomePageState extends State<MyHomePage> {
       return _buildFlowyEditorWithEmptyDocument();
     } else if (page == 2) {
       return _buildTextField();
+    } else if (page == 3) {
+      return _buildFlowyEditorWithBigDocument();
     }
     return Container();
   }
@@ -205,4 +216,34 @@ class _MyHomePageState extends State<MyHomePage> {
       child: TextField(),
     );
   }
+
+  Widget _buildFlowyEditorWithBigDocument() {
+    return FutureBuilder<String>(
+      future: rootBundle.loadString('assets/big_document.json'),
+      builder: (context, snapshot) {
+        if (!snapshot.hasData) {
+          return const Center(
+            child: CircularProgressIndicator(),
+          );
+        } else {
+          final data = Map<String, Object>.from(json.decode(snapshot.data!));
+          final document = StateTree.fromJson(data);
+          _editorState = EditorState(
+            document: document,
+          );
+          return Container(
+            padding: const EdgeInsets.only(left: 20, right: 20),
+            child: FlowyEditor(
+              key: editorKey,
+              editorState: _editorState,
+              keyEventHandlers: const [],
+              customBuilders: {
+                'image': ImageNodeBuilder(),
+              },
+            ),
+          );
+        }
+      },
+    );
+  }
 }

frontend/app_flowy/packages/flowy_editor/example/pubspec.yaml

@@ -68,6 +68,7 @@ flutter:
   assets:
     - document.json
     - example.json
+    - big_document.json
   #   - images/a_dot_ham.jpeg
 
   # An image asset can refer to one or more resolution-specific "variants", see

frontend/app_flowy/packages/flowy_editor/lib/extensions/node_extensions.dart

@@ -19,4 +19,12 @@ extension NodeExtensions on Node {
       return selection.end.path <= path && path <= selection.start.path;
     }
   }
+
+  Rect get rect {
+    if (renderBox != null) {
+      final boxOffset = renderBox!.localToGlobal(Offset.zero);
+      return boxOffset & renderBox!.size;
+    }
+    return Rect.zero;
+  }
 }

frontend/app_flowy/packages/flowy_editor/lib/service/selection_service.dart

@@ -359,12 +359,14 @@ class _FlowySelectionState extends State<FlowySelection>
       panStartOffsetWithScrollDyGap =
           panStartOffsetWithScrollDyGap.translate(0, panStartScrollDy! - dy);
     }
-    final nodes = getNodesInRange(panStartOffsetWithScrollDyGap, panEndOffset!);
-    if (nodes.isEmpty) {
-      return;
-    }
-    final first = nodes.first.selectable;
-    final last = nodes.last.selectable;
+
+    final sortedNodes =
+        editorState.document.root.children.toList(growable: false);
+    final first = _lowerBound(
+            sortedNodes, panStartOffsetWithScrollDyGap, 0, sortedNodes.length)
+        .selectable;
+    final last = _upperBound(sortedNodes, panEndOffset!, 0, sortedNodes.length)
+        .selectable;
 
     // compute the selection in range.
     if (first != null && last != null) {
@@ -559,6 +561,41 @@ class _FlowySelectionState extends State<FlowySelection>
       }
     }
   }
+
+  // find the first node's rect.top <= offset.dy
+  Node _lowerBound(List<Node> sortedNodes, Offset offset, int start, int end) {
+    var min = start;
+    var max = end;
+    while (min <= max) {
+      final mid = min + ((max - min) >> 1);
+      if (sortedNodes[mid].rect.bottom <= offset.dy) {
+        min = mid + 1;
+      } else {
+        max = mid - 1;
+      }
+    }
+    return sortedNodes[min];
+  }
+
+  // find the first node's rect.top < offset.dy
+  Node _upperBound(
+    List<Node> sortedNodes,
+    Offset offset,
+    int start,
+    int end,
+  ) {
+    var min = start;
+    var max = end;
+    while (min <= max) {
+      final mid = min + ((max - min) >> 1);
+      if (sortedNodes[mid].rect.top < offset.dy) {
+        min = mid + 1;
+      } else {
+        max = mid - 1;
+      }
+    }
+    return sortedNodes[max];
+  }
 }
 
 /// Because the flutter's [DoubleTapGestureRecognizer] will block the [TapGestureRecognizer]