field_of_view #

A Flutter plugin to get the camera's field of view (FOV) on iOS and Android.

Features #

• Get horizontal and vertical field of view angles from the back camera
• No camera permissions required
• Strongly-typed API using Pigeon
• Supports iOS and Android

Installation #

Add this to your package's pubspec.yaml file:

dependencies:
  field_of_view: ^0.0.1

Usage #

import 'package:field_of_view/field_of_view.dart';

final fov = FieldOfView();

try {
  final response = await fov.getFieldOfView();
  print('Horizontal FOV: ${response.horizontalFov}°');
  print('Vertical FOV: ${response.verticalFov}°');
} on PlatformException catch (e) {
  print('Error: ${e.message}');
}

Response #

The FieldOfViewResponse contains:

Note: The FOV values represent the camera sensor's native orientation (landscape), so horizontal FOV will typically be larger than vertical FOV, regardless of device orientation.

Error handling #

The plugin throws PlatformException with the following error codes:

How it works #

• iOS: Uses AVCaptureDevice.Format.geometricDistortionCorrectedVideoFieldOfView for horizontal FOV (corrected for lens distortion) and calculates vertical FOV from the aspect ratio. Requires iOS 13.0+.

• Android: Uses Camera2 API to read SENSOR_INFO_PHYSICAL_SIZE and LENS_INFO_AVAILABLE_FOCAL_LENGTHS from CameraCharacteristics, then calculates FOV using the pinhole camera model:

FOV = 2 × atan(sensorSize / (2 × focalLength))