Avoid too close points being added to a drawing_line

lib/features/sheet_viewer/drawing/drawing_controller.dart

@@ -64,9 +64,11 @@ class DrawingController extends ChangeNotifier {
   void addPoint(Offset normalizedPoint) {
     if (_currentLine == null) return;
 
+    if (!currentLine!.isPointTooClose(normalizedPoint)) {
       _currentLine = _currentLine!.addPoint(normalizedPoint);
       notifyListeners();
     }
+  }
 
   /// Completes the current line and adds it to the history.
   void endLine() {

lib/features/sheet_viewer/drawing/drawing_line.dart

@@ -8,6 +8,9 @@ import 'dart:ui';
 ///
 /// This allows drawings to scale correctly when the canvas size changes.
 class DrawingLine {
+  /// The minimal squared distance between to points which are normalized so that this point is allowed to be added to the line
+  static const minNormalizedPointDistanceSquared = 0.001 * 0.001;
+
   /// Points in normalized coordinates (0.0 to 1.0)
   final List<Offset> points;
 
@@ -27,10 +30,9 @@ class DrawingLine {
   /// Creates a DrawingLine from JSON data.
   factory DrawingLine.fromJson(Map<String, dynamic> json) {
     final pointsList = (json['points'] as List)
-        .map((p) => Offset(
-              (p['x'] as num).toDouble(),
-              (p['y'] as num).toDouble(),
-            ))
+        .map(
+          (p) => Offset((p['x'] as num).toDouble(), (p['y'] as num).toDouble()),
+        )
         .toList();
 
     return DrawingLine(
@@ -58,6 +60,14 @@ class DrawingLine {
     );
   }
 
+  bool isPointTooClose(Offset nextNormalizedPoint) {
+    if (points.isEmpty) {
+      return false;
+    }
+    return (points.last - nextNormalizedPoint).distanceSquared <
+        minNormalizedPointDistanceSquared;
+  }
+
   /// Creates a copy with updated points.
   DrawingLine copyWith({
     List<Offset>? points,
@@ -85,9 +95,5 @@ class DrawingLine {
   }
 
   @override
-  int get hashCode => Object.hash(
-        Object.hashAll(points),
-        color,
-        strokeWidth,
-      );
+  int get hashCode => Object.hash(Object.hashAll(points), color, strokeWidth);
 }