Added method to retrieve min supported zoom level

Author: mvanbeusekom

packages/camera/camera_platform_interface/lib/src/method_channel/method_channel_camera.dart

@@ -181,6 +181,12 @@ class MethodChannelCamera extends CameraPlatform {
         <String, dynamic>{'cameraId': cameraId},
       );
 
+  @override
+  Future<double> getMinZoomLevel(int cameraId) => _channel.invokeMethod<double>(
+        'getMinZoomLevel',
+        <String, dynamic>{'cameraId': cameraId},
+      );
+
   @override
   Future<void> setZoomLevel(int cameraId, double zoom) async {
     try {

packages/camera/camera_platform_interface/lib/src/platform_interface/camera_platform.dart

@@ -113,6 +113,11 @@ abstract class CameraPlatform extends PlatformInterface {
     throw UnimplementedError('getMaxZoomLevel() is not implemented.');
   }
 
+  /// Gets the minimum supported zoom level for the selected camera.
+  Future<double> getMinZoomLevel(int cameraId) {
+    throw UnimplementedError('getMinZoomLevel() is not implemented.');
+  }
+
   /// Set the zoom level for the selected camera.
   ///
   /// The supplied [zoom] value should be between 1.0 and the maximum supported

packages/camera/camera_platform_interface/test/camera_platform_interface_test.dart

@@ -225,6 +225,19 @@ void main() {
       );
     });
 
+    test(
+        'Default implementation of getMinZoomLevel() should throw unimplemented error',
+        () {
+      // Arrange
+      final cameraPlatform = ExtendsCameraPlatform();
+
+      // Act & Assert
+      expect(
+        () => cameraPlatform.getMinZoomLevel(1),
+        throwsUnimplementedError,
+      );
+    });
+
     test(
         'Default implementation of setZoomLevel() should throw unimplemented error',
         () {

packages/camera/camera_platform_interface/test/method_channel/method_channel_camera_test.dart

@@ -506,6 +506,25 @@ void main() {
         ]);
       });
 
+      test('Should get the min zoom level', () async {
+        // Arrange
+        MethodChannelMock channel = MethodChannelMock(
+          channelName: 'plugins.flutter.io/camera',
+          methods: {'getMinZoomLevel': 1.0},
+        );
+
+        // Act
+        final maxZoomLevel = await camera.getMinZoomLevel(cameraId);
+
+        // Assert
+        expect(maxZoomLevel, 1.0);
+        expect(channel.log, <Matcher>[
+          isMethodCall('getMinZoomLevel', arguments: {
+            'cameraId': cameraId,
+          }),
+        ]);
+      });
+
       test('Should set the zoom level', () async {
         // Arrange
         MethodChannelMock channel = MethodChannelMock(