add params to set resolution (#46)

Author: kevin-sakemaer

lib/flutter_camera_ml_vision.dart

@@ -38,6 +38,7 @@ class CameraMlVision<T> extends StatefulWidget {
   final ErrorWidgetBuilder errorBuilder;
   final WidgetBuilder overlayBuilder;
   final CameraLensDirection cameraLensDirection;
+  final ResolutionPreset resolution;
 
   CameraMlVision({
     Key key,
@@ -47,6 +48,7 @@ class CameraMlVision<T> extends StatefulWidget {
     this.errorBuilder,
     this.overlayBuilder,
     this.cameraLensDirection = CameraLensDirection.back,
+    this.resolution,
   }) : super(key: key);
 
   @override
@@ -160,7 +162,9 @@ class CameraMlVisionState<T> extends State<CameraMlVision<T>> {
     }
     _cameraController = CameraController(
       description,
-      Platform.isIOS ? ResolutionPreset.low : ResolutionPreset.medium,
+      widget.resolution ?? Platform.isIOS
+          ? ResolutionPreset.low
+          : ResolutionPreset.medium,
       enableAudio: false,
     );
     if (!mounted) {