Implement possibility to resize the crop area

README.md

@@ -5,7 +5,7 @@ A Flutter plugin enabling the user to detect edges of a given image. It returns
 ## Demo
 
 <p align="center">
-  <img src="https://www.flutterclutter.dev/wp-content/uploads/2020/09/flutter-edge-detection-animation.gif" height=600>
+  <img src="https://www.flutterclutter.dev/wp-content/uploads/2020/09/flutter-edge-detection-drag-animation.gif" height=600>
 </p>
 
 ## Try out

example/lib/edge_detection_shape/animated_touch_bubble_part.dart

@@ -0,0 +1,85 @@
+import 'package:flutter/material.dart';
+
+class AnimatedTouchBubblePart extends StatefulWidget {
+  AnimatedTouchBubblePart({this.dragging, this.size});
+
+  final bool dragging;
+  final double size;
+
+  @override
+  _AnimatedTouchBubblePartState createState() => _AnimatedTouchBubblePartState();
+}
+
+class _AnimatedTouchBubblePartState extends State<AnimatedTouchBubblePart> with SingleTickerProviderStateMixin  {
+  AnimationController _controller;
+  Animation<Color> _colorAnimation;
+  Animation<double> _sizeAnimation;
+
+  @override
+  void didChangeDependencies() {
+    _controller = new AnimationController(
+      duration: const Duration(milliseconds: 1000),
+      vsync: this,
+    );
+
+    _sizeAnimation = Tween<double>(
+        begin: 0.5,
+        end: 1.0
+    ).animate(_controller);
+
+    _colorAnimation = ColorTween(
+        begin: Theme.of(context).accentColor.withOpacity(0.5),
+        end: Theme.of(context).accentColor.withOpacity(0.0)
+    ).animate(
+        CurvedAnimation(
+            parent: _controller,
+            curve: Interval(0.5, 1.0)
+        )
+    );
+
+    _controller.repeat();
+    super.didChangeDependencies();
+  }
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Stack(
+      children: [
+        Center(
+          child: Container(
+            width: widget.dragging ? widget.size : widget.size / 2,
+            height: widget.dragging ? widget.size : widget.size / 2,
+            decoration: BoxDecoration(
+                color: Theme.of(context).accentColor.withOpacity(0.5),
+                borderRadius: widget.dragging ? BorderRadius.circular(widget.size) : BorderRadius.circular(widget.size / 4)
+            )
+          )
+        ),
+        AnimatedBuilder(
+            builder: (BuildContext context, Widget child) {
+              return Center(
+                child: Container(
+                  width: widget.dragging ? 0 : widget.size * _sizeAnimation.value,
+                  height: widget.dragging ? 0 : widget.size  * _sizeAnimation.value,
+                  decoration: BoxDecoration(
+                    border: Border.all(
+                        color: _colorAnimation.value,
+                        width: widget.size / 20
+                    ),
+                    borderRadius: widget.dragging ? BorderRadius.zero : BorderRadius.circular(widget.size * _sizeAnimation.value / 2)
+                  )
+                )
+              );
+            },
+            animation: _controller
+        )
+      ],
+    );
+  }
+}