first commit

lib/modules/camera/outside_dim_mask.dart

@@ -0,0 +1,69 @@
+import 'package:flutter/material.dart';
+
+class OutsideDimMask extends StatelessWidget {
+  final double opacity;
+  const OutsideDimMask({super.key, this.opacity = 0.6});
+
+  @override
+  Widget build(BuildContext context) {
+    const a5Ratio = 148 / 210;
+
+    return LayoutBuilder(
+      builder: (context, constraints) {
+        final width = constraints.maxWidth;
+        final height = constraints.maxHeight;
+
+        double frameWidth;
+        double frameHeight;
+
+        if (width / height > a5Ratio) {
+          frameHeight = height;
+          frameWidth = height * a5Ratio;
+        } else {
+          frameWidth = width;
+          frameHeight = width / a5Ratio;
+        }
+
+        final left = (width - frameWidth) / 2;
+        final top = (height - frameHeight) / 2;
+
+        return Stack(
+          children: [
+            // Top
+            Positioned(
+              left: 0,
+              right: 0,
+              top: 0,
+              height: top,
+              child: Container(color: Colors.black.withOpacity(opacity)),
+            ),
+            // Bottom
+            Positioned(
+              left: 0,
+              right: 0,
+              bottom: 0,
+              height: top,
+              child: Container(color: Colors.black.withOpacity(opacity)),
+            ),
+            // Left
+            Positioned(
+              left: 0,
+              top: top,
+              width: left,
+              height: frameHeight,
+              child: Container(color: Colors.black.withOpacity(opacity)),
+            ),
+            // Right
+            Positioned(
+              right: 0,
+              top: top,
+              width: left,
+              height: frameHeight,
+              child: Container(color: Colors.black.withOpacity(opacity)),
+            ),
+          ],
+        );
+      },
+    );
+  }
+}