取色器取色点移出屏幕会出现取色异常的bug

kits/flutter_ume_kit_ui/lib/components/color_sucker/color_sucker.dart

@@ -75,21 +75,35 @@ class _ColorSuckerState extends State<ColorSucker> {
   }
 
   void _onPanUpdate(DragUpdateDetails dragDetails) {
-    _magnifierPosition =
-        dragDetails.globalPosition - _magnifierSize.center(Offset.zero);
     double newX = dragDetails.globalPosition.dx;
     double newY = dragDetails.globalPosition.dy;
+    if (newX + (_magnifierSize.width / 2) < 0) {
+      newX = 0;
+    } else if (newX >= _windowSize.width) {
+      newX = _windowSize.width - 1;
+    }
+
+    if (newY + (_magnifierSize.height / 2) < 0) {
+      newY = 0;
+    } else if (newY + (_magnifierSize.height / 2) > _windowSize.height) {
+      newY = _windowSize.height - 1;
+    }
+
+    _magnifierPosition =
+        Offset(newX, newY) - _magnifierSize.center(Offset.zero);
+
     final Matrix4 newMatrix = Matrix4.identity()
       ..translate(newX, newY)
       ..scale(_scale, _scale)
       ..translate(-newX, -newY);
     _matrix = newMatrix;
-    _searchPixel(dragDetails.globalPosition);
+    _searchPixel(Offset(newX, newY));
     setState(() {});
   }
 
   void _toolBarPanUpdate(DragUpdateDetails dragDetails) {
     _toolBarY = dragDetails.globalPosition.dy - 40;
+    if (_toolBarY <= 0) _toolBarY = 0;
     setState(() {});
   }