simple_custom_focus_camera

A Flutter package for custom camera functionality with native Android implementation. This package is specifically designed for use cases requiring manual focus control (e.g., locking focus to a near distance) and provides a highly-optimized camera preview that avoids common stretching and cropping issues.

Preview

Features

Aspect-Ratio Fixed Preview: Automatically handles various camera sensor orientations and aspect ratios to ensure the preview is never stretched or skewed.
Center-Fit Transform: The preview fits the view perfectly without the common width/height cropping issues.
Configurable Focus Distance: Lock the camera to a specific focus distance (in meters), ideal for scanning or close-up photography.
Manual Focus Support: Toggle between continuous auto-focus and manual focus.
Front/Back Camera Selection: Easily switch between front and back-facing cameras.
Still Image Capture: Directly capture images from the camera stream.

Installation

Add simple_custom_focus_camera to your pubspec.yaml:

dependencies:
  simple_custom_focus_camera: ^1.0.0

Android Setup

Ensure your minSdkVersion is at least 21 (Required for Camera2 API).

Add the following permission to your AndroidManifest.xml:

<uses-permission android:name="android.permission.CAMERA" />

Usage

Simple Implementation

import 'package:flutter/material.dart';
import 'package:simple_custom_focus_camera/simple_custom_focus_camera.dart';

class CameraScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: CustomCameraView(
        facing: 'back',
        useManualFocus: true,
        focusDistanceMeters: 0.1, // Focus distance in meters
        onImageCaptured: (Uint8List bytes) {
          // Handle captured image
        },
      ),
    );
  }
}

Advanced Control

You can use the CustomCameraView to configure settings dynamically:

// Example of dynamic configuration via MethodChannel or controller (depending on plugin implementation)

How it works

This plugin addresses a common problem in Android Camera2 implementations where the TextureView preview appears stretched or cropped when the view aspect ratio doesn't match the sensor's supported output sizes. It specifically calculates a fit-inside transform matrix and selects optimal preview sizes based on the actual TextureView dimensions, accounting for sensor rotation.

License

This project is licensed under the MIT License - see the LICENSE file for details.