feat: add animation during auto scrolling (#1153)

lib/src/editor/editor_component/service/scroll/auto_scroller.dart

@@ -20,6 +20,7 @@ class AutoScroller extends EdgeDraggingAutoScroller
     super.velocityScalar = _kDefaultAutoScrollVelocityScalar,
     super.minimumAutoScrollDelta = _kDefaultMinAutoScrollDelta,
     super.maxAutoScrollDelta = _kDefaultMaxAutoScrollDelta,
+    super.animationDuration,
   });
 
   static const double _kDefaultAutoScrollVelocityScalar = 7;
@@ -28,6 +29,8 @@ class AutoScroller extends EdgeDraggingAutoScroller
 
   Offset? lastOffset;
   Duration? lastDuration;
+  double? lastEdgeOffset;
+  AxisDirection? lastDirection;
 
   @override
   void startAutoScroll(
@@ -38,9 +41,12 @@ class AutoScroller extends EdgeDraggingAutoScroller
   }) {
     lastOffset = offset;
     lastDuration = duration;
+    lastEdgeOffset = edgeOffset;
+    lastDirection = direction;
     if (direction != null && direction == AxisDirection.up) {
       return startAutoScrollIfNecessary(
         offset & Size(1, edgeOffset),
+        duration: duration,
       );
     }
 
@@ -52,6 +58,7 @@ class AutoScroller extends EdgeDraggingAutoScroller
 
     startAutoScrollIfNecessary(
       dragTarget,
+      duration: duration,
     );
   }
 
@@ -59,6 +66,8 @@ class AutoScroller extends EdgeDraggingAutoScroller
   void stopAutoScroll() {
     lastOffset = null;
     lastDuration = null;
+    lastEdgeOffset = null;
+    lastDirection = null;
     super.stopAutoScroll();
   }
 
@@ -66,6 +75,8 @@ class AutoScroller extends EdgeDraggingAutoScroller
     if (lastOffset != null) {
       startAutoScroll(
         lastOffset!,
+        edgeOffset: lastEdgeOffset ?? 200,
+        direction: lastDirection,
         duration: lastDuration,
       );
     }

lib/src/editor/editor_component/service/scroll_service_widget.dart

@@ -101,6 +101,14 @@ class _ScrollServiceWidgetState extends State<ScrollServiceWidget>
       AxisDirection? direction;
       final dynamic dragMode =
           editorState.selectionExtraInfo?['selection_drag_mode'];
+
+      // For desktop: if auto-scroller is already scrolling (from drag-to-select),
+      // don't override it here. The desktop_selection_service handles drag scrolling.
+      if (PlatformExtension.isDesktopOrWeb &&
+          (editorState.autoScroller?.scrolling ?? false)) {
+        return;
+      }
+
       switch (dragMode?.toString()) {
         case 'MobileSelectionDragMode.leftSelectionHandle':
           targetRect = selectionRects.first;

lib/src/editor/editor_component/service/selection/desktop_selection_service.dart

@@ -345,7 +345,8 @@ class _DesktopSelectionServiceWidgetState
 
     editorState.service.scrollService?.startAutoScroll(
       _lastPanOffset!,
-      edgeOffset: 80,
+      edgeOffset: 200,
+      duration: const Duration(milliseconds: 2),
     );
   }
 

lib/src/editor_state.dart

@@ -636,9 +636,10 @@ class EditorState {
       late AutoScroller scroller;
       scroller = AutoScroller(
         scrollableState,
-        velocityScalar: isDesktopOrWeb ? 0.125 : 0.02,
+        velocityScalar: isDesktopOrWeb ? 0.15 : 0.02,
         minimumAutoScrollDelta: isDesktopOrWeb ? 0.07 : 0.004,
-        maxAutoScrollDelta: isDesktopOrWeb ? 2.75 : 0.053,
+        maxAutoScrollDelta: isDesktopOrWeb ? 3.5 : 0.053,
+        animationDuration: Duration.zero,
         onScrollViewScrolled: () {
           _notifyScrollViewScrolledListeners();
           if (!isDesktopOrWeb) {

lib/src/flutter/scrollable_helpers.dart

@@ -150,10 +150,13 @@ class EdgeDraggingAutoScroller {
     required this.velocityScalar,
     double minimumAutoScrollDelta = 1.0,
     double maxAutoScrollDelta = 20.0,
+    Duration? animationDuration,
   })  : assert(minimumAutoScrollDelta >= 0),
         assert(maxAutoScrollDelta >= minimumAutoScrollDelta),
         _minimumAutoScrollDelta = minimumAutoScrollDelta,
-        _maxAutoScrollDelta = maxAutoScrollDelta;
+        _maxAutoScrollDelta = maxAutoScrollDelta,
+        _animationDuration =
+            animationDuration ?? const Duration(milliseconds: 5);
 
   /// The [Scrollable] this auto scroller is scrolling.
   final ScrollableState scrollable;
@@ -180,6 +183,8 @@ class EdgeDraggingAutoScroller {
   /// moving rather than treat it as too small to scroll.
   final double _minimumAutoScrollDelta;
   final double _maxAutoScrollDelta;
+  final Duration _animationDuration;
+  Duration? _currentDuration;
   double? _previousScrollDelta;
 
   late Rect _dragTargetRelatedToScrollOrigin;
@@ -212,10 +217,11 @@ class EdgeDraggingAutoScroller {
   ///
   /// If the scrollable is already scrolling, calling this method updates the
   /// previous dragTarget to the new value and continues scrolling if necessary.
-  void startAutoScrollIfNecessary(Rect dragTarget) {
+  void startAutoScrollIfNecessary(Rect dragTarget, {Duration? duration}) {
     final Offset deltaToOrigin = scrollable.deltaToScrollOrigin;
     _dragTargetRelatedToScrollOrigin =
         dragTarget.translate(deltaToOrigin.dx, deltaToOrigin.dy);
+    _currentDuration = duration;
     if (_scrolling) {
       // The change will be picked up in the next scroll.
       return;
@@ -228,9 +234,10 @@ class EdgeDraggingAutoScroller {
   void stopAutoScroll() {
     _scrolling = false;
     _previousScrollDelta = null;
+    _currentDuration = null;
   }
 
-  Future<void> _scroll({Duration? duration}) async {
+  Future<void> _scroll() async {
     try {
       final RenderBox scrollRenderBox =
           scrollable.context.findRenderObject()! as RenderBox;
@@ -354,13 +361,13 @@ class EdgeDraggingAutoScroller {
       }
       await scrollable.position.moveTo(
         newOffset,
-        duration: duration,
+        duration: _currentDuration ?? _animationDuration,
         curve: Curves.linear,
-        clamp: true,
+        // clamp: true,
       );
       onScrollViewScrolled?.call();
       if (_scrolling) {
-        await _scroll(duration: duration);
+        await _scroll();
       }
     } catch (e) {
       debugPrint(e.toString());