packages/camera/camera/ios/Classes/CameraPlugin.m

// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#import "CameraPlugin.h"
#import "CameraPlugin_Test.h"

@import AVFoundation;

#import "CameraPermissionUtils.h"
#import "CameraProperties.h"
#import "FLTCam.h"
#import "FLTThreadSafeEventChannel.h"
#import "FLTThreadSafeFlutterResult.h"
#import "FLTThreadSafeMethodChannel.h"
#import "FLTThreadSafeTextureRegistry.h"
#import "QueueUtils.h"

@interface CameraPlugin ()
@property(readonly, nonatomic) FLTThreadSafeTextureRegistry *registry;
@property(readonly, nonatomic) NSObject<FlutterBinaryMessenger> *messenger;
@property(readonly, nonatomic) FLTThreadSafeMethodChannel *deviceEventMethodChannel;
@end

@implementation CameraPlugin

+ (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar> *)registrar {
  FlutterMethodChannel *channel =
      [FlutterMethodChannel methodChannelWithName:@"plugins.flutter.io/camera"
                                  binaryMessenger:[registrar messenger]];
  CameraPlugin *instance = [[CameraPlugin alloc] initWithRegistry:[registrar textures]
                                                        messenger:[registrar messenger]];
  [registrar addMethodCallDelegate:instance channel:channel];
}

- (instancetype)initWithRegistry:(NSObject<FlutterTextureRegistry> *)registry
                       messenger:(NSObject<FlutterBinaryMessenger> *)messenger {
  self = [super init];
  NSAssert(self, @"super init cannot be nil");
  _registry = [[FLTThreadSafeTextureRegistry alloc] initWithTextureRegistry:registry];
  _messenger = messenger;
  _captureSessionQueue = dispatch_queue_create("io.flutter.camera.captureSessionQueue", NULL);
  dispatch_queue_set_specific(_captureSessionQueue, FLTCaptureSessionQueueSpecific,
                              (void *)FLTCaptureSessionQueueSpecific, NULL);

  [self initDeviceEventMethodChannel];
  [self startOrientationListener];
  return self;
}

- (void)initDeviceEventMethodChannel {
  FlutterMethodChannel *methodChannel =
      [FlutterMethodChannel methodChannelWithName:@"flutter.io/cameraPlugin/device"
                                  binaryMessenger:_messenger];
  _deviceEventMethodChannel =
      [[FLTThreadSafeMethodChannel alloc] initWithMethodChannel:methodChannel];
}

- (void)startOrientationListener {
  [[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
  [[NSNotificationCenter defaultCenter] addObserver:self
                                           selector:@selector(orientationChanged:)
                                               name:UIDeviceOrientationDidChangeNotification
                                             object:[UIDevice currentDevice]];
}

- (void)orientationChanged:(NSNotification *)note {
  UIDevice *device = note.object;
  UIDeviceOrientation orientation = device.orientation;

  if (orientation == UIDeviceOrientationFaceUp || orientation == UIDeviceOrientationFaceDown) {
    // Do not change when oriented flat.
    return;
  }

  dispatch_async(self.captureSessionQueue, ^{
    // `FLTCam::setDeviceOrientation` must be called on capture session queue.
    [self.camera setDeviceOrientation:orientation];
    // `CameraPlugin::sendDeviceOrientation` can be called on any queue.
    [self sendDeviceOrientation:orientation];
  });
}

- (void)sendDeviceOrientation:(UIDeviceOrientation)orientation {
  [_deviceEventMethodChannel
      invokeMethod:@"orientation_changed"
         arguments:@{@"orientation" : FLTGetStringForUIDeviceOrientation(orientation)}];
}

- (void)handleMethodCall:(FlutterMethodCall *)call result:(FlutterResult)result {
  // Invoke the plugin on another dispatch queue to avoid blocking the UI.
  dispatch_async(_captureSessionQueue, ^{
    FLTThreadSafeFlutterResult *threadSafeResult =
        [[FLTThreadSafeFlutterResult alloc] initWithResult:result];

    [self handleMethodCallAsync:call result:threadSafeResult];
  });
}

- (void)handleMethodCallAsync:(FlutterMethodCall *)call
                       result:(FLTThreadSafeFlutterResult *)result {
  if ([@"availableCameras" isEqualToString:call.method]) {
    if (@available(iOS 10.0, *)) {
      AVCaptureDeviceDiscoverySession *discoverySession = [AVCaptureDeviceDiscoverySession
          discoverySessionWithDeviceTypes:@[ AVCaptureDeviceTypeBuiltInWideAngleCamera ]
                                mediaType:AVMediaTypeVideo
                                 position:AVCaptureDevicePositionUnspecified];
      NSArray<AVCaptureDevice *> *devices = discoverySession.devices;
      NSMutableArray<NSDictionary<NSString *, NSObject *> *> *reply =
          [[NSMutableArray alloc] initWithCapacity:devices.count];
      for (AVCaptureDevice *device in devices) {
        NSString *lensFacing;
        switch ([device position]) {
          case AVCaptureDevicePositionBack:
            lensFacing = @"back";
            break;
          case AVCaptureDevicePositionFront:
            lensFacing = @"front";
            break;
          case AVCaptureDevicePositionUnspecified:
            lensFacing = @"external";
            break;
        }
        [reply addObject:@{
          @"name" : [device uniqueID],
          @"lensFacing" : lensFacing,
          @"sensorOrientation" : @90,
        }];
      }
      [result sendSuccessWithData:reply];
    } else {
      [result sendNotImplemented];
    }
  } else if ([@"create" isEqualToString:call.method]) {
    [self handleCreateMethodCall:call result:result];
  } else if ([@"startImageStream" isEqualToString:call.method]) {
    [_camera startImageStreamWithMessenger:_messenger];
    [result sendSuccess];
  } else if ([@"stopImageStream" isEqualToString:call.method]) {
    [_camera stopImageStream];
    [result sendSuccess];
  } else if ([@"receivedImageStreamData" isEqualToString:call.method]) {
    [_camera receivedImageStreamData];
    [result sendSuccess];
  } else {
    NSDictionary *argsMap = call.arguments;
    NSUInteger cameraId = ((NSNumber *)argsMap[@"cameraId"]).unsignedIntegerValue;
    if ([@"initialize" isEqualToString:call.method]) {
      NSString *videoFormatValue = ((NSString *)argsMap[@"imageFormatGroup"]);
      [_camera setVideoFormat:FLTGetVideoFormatFromString(videoFormatValue)];

      __weak CameraPlugin *weakSelf = self;
      _camera.onFrameAvailable = ^{
        if (![weakSelf.camera isPreviewPaused]) {
          [weakSelf.registry textureFrameAvailable:cameraId];
        }
      };
      FlutterMethodChannel *methodChannel = [FlutterMethodChannel
          methodChannelWithName:[NSString stringWithFormat:@"flutter.io/cameraPlugin/camera%lu",
                                                           (unsigned long)cameraId]
                binaryMessenger:_messenger];
      FLTThreadSafeMethodChannel *threadSafeMethodChannel =
          [[FLTThreadSafeMethodChannel alloc] initWithMethodChannel:methodChannel];
      _camera.methodChannel = threadSafeMethodChannel;
      [threadSafeMethodChannel
          invokeMethod:@"initialized"
             arguments:@{
               @"previewWidth" : @(_camera.previewSize.width),
               @"previewHeight" : @(_camera.previewSize.height),
               @"exposureMode" : FLTGetStringForFLTExposureMode([_camera exposureMode]),
               @"focusMode" : FLTGetStringForFLTFocusMode([_camera focusMode]),
               @"exposurePointSupported" :
                   @([_camera.captureDevice isExposurePointOfInterestSupported]),
               @"focusPointSupported" : @([_camera.captureDevice isFocusPointOfInterestSupported]),
             }];
      [self sendDeviceOrientation:[UIDevice currentDevice].orientation];
      [_camera start];
      [result sendSuccess];
    } else if ([@"takePicture" isEqualToString:call.method]) {
      if (@available(iOS 10.0, *)) {
        [_camera captureToFile:result];
      } else {
        [result sendNotImplemented];
      }
    } else if ([@"dispose" isEqualToString:call.method]) {
      [_registry unregisterTexture:cameraId];
      [_camera close];
      [result sendSuccess];
    } else if ([@"prepareForVideoRecording" isEqualToString:call.method]) {
      [self.camera setUpCaptureSessionForAudio];
      [result sendSuccess];
    } else if ([@"startVideoRecording" isEqualToString:call.method]) {
      [_camera startVideoRecordingWithResult:result];
    } else if ([@"stopVideoRecording" isEqualToString:call.method]) {
      [_camera stopVideoRecordingWithResult:result];
    } else if ([@"pauseVideoRecording" isEqualToString:call.method]) {
      [_camera pauseVideoRecordingWithResult:result];
    } else if ([@"resumeVideoRecording" isEqualToString:call.method]) {
      [_camera resumeVideoRecordingWithResult:result];
    } else if ([@"getMaxZoomLevel" isEqualToString:call.method]) {
      [_camera getMaxZoomLevelWithResult:result];
    } else if ([@"getMinZoomLevel" isEqualToString:call.method]) {
      [_camera getMinZoomLevelWithResult:result];
    } else if ([@"setZoomLevel" isEqualToString:call.method]) {
      CGFloat zoom = ((NSNumber *)argsMap[@"zoom"]).floatValue;
      [_camera setZoomLevel:zoom Result:result];
    } else if ([@"setFlashMode" isEqualToString:call.method]) {
      [_camera setFlashModeWithResult:result mode:call.arguments[@"mode"]];
    } else if ([@"setExposureMode" isEqualToString:call.method]) {
      [_camera setExposureModeWithResult:result mode:call.arguments[@"mode"]];
    } else if ([@"setExposurePoint" isEqualToString:call.method]) {
      BOOL reset = ((NSNumber *)call.arguments[@"reset"]).boolValue;
      double x = 0.5;
      double y = 0.5;
      if (!reset) {
        x = ((NSNumber *)call.arguments[@"x"]).doubleValue;
        y = ((NSNumber *)call.arguments[@"y"]).doubleValue;
      }
      [_camera setExposurePointWithResult:result x:x y:y];
    } else if ([@"getMinExposureOffset" isEqualToString:call.method]) {
      [result sendSuccessWithData:@(_camera.captureDevice.minExposureTargetBias)];
    } else if ([@"getMaxExposureOffset" isEqualToString:call.method]) {
      [result sendSuccessWithData:@(_camera.captureDevice.maxExposureTargetBias)];
    } else if ([@"getExposureOffsetStepSize" isEqualToString:call.method]) {
      [result sendSuccessWithData:@(0.0)];
    } else if ([@"setExposureOffset" isEqualToString:call.method]) {
      [_camera setExposureOffsetWithResult:result
                                    offset:((NSNumber *)call.arguments[@"offset"]).doubleValue];
    } else if ([@"lockCaptureOrientation" isEqualToString:call.method]) {
      [_camera lockCaptureOrientationWithResult:result orientation:call.arguments[@"orientation"]];
    } else if ([@"unlockCaptureOrientation" isEqualToString:call.method]) {
      [_camera unlockCaptureOrientationWithResult:result];
    } else if ([@"setFocusMode" isEqualToString:call.method]) {
      [_camera setFocusModeWithResult:result mode:call.arguments[@"mode"]];
    } else if ([@"setFocusPoint" isEqualToString:call.method]) {
      BOOL reset = ((NSNumber *)call.arguments[@"reset"]).boolValue;
      double x = 0.5;
      double y = 0.5;
      if (!reset) {
        x = ((NSNumber *)call.arguments[@"x"]).doubleValue;
        y = ((NSNumber *)call.arguments[@"y"]).doubleValue;
      }
      [_camera setFocusPointWithResult:result x:x y:y];
    } else if ([@"pausePreview" isEqualToString:call.method]) {
      [_camera pausePreviewWithResult:result];
    } else if ([@"resumePreview" isEqualToString:call.method]) {
      [_camera resumePreviewWithResult:result];
    } else {
      [result sendNotImplemented];
    }
  }
}

- (void)handleCreateMethodCall:(FlutterMethodCall *)call
                        result:(FLTThreadSafeFlutterResult *)result {
  // Create FLTCam only if granted camera access (and audio access if audio is enabled)
  FLTRequestCameraPermissionWithCompletionHandler(^(FlutterError *error) {
    if (error) {
      [result sendFlutterError:error];
    } else {
      // Request audio permission on `create` call with `enableAudio` argument instead of the
      // `prepareForVideoRecording` call. This is because `prepareForVideoRecording` call is
      // optional, and used as a workaround to fix a missing frame issue on iOS.
      BOOL audioEnabled = [call.arguments[@"enableAudio"] boolValue];
      if (audioEnabled) {
        // Setup audio capture session only if granted audio access.
        FLTRequestAudioPermissionWithCompletionHandler(^(FlutterError *error) {
          if (error) {
            [result sendFlutterError:error];
          } else {
            [self createCameraOnSessionQueueWithCreateMethodCall:call result:result];
          }
        });
      } else {
        [self createCameraOnSessionQueueWithCreateMethodCall:call result:result];
      }
    }
  });
}

- (void)createCameraOnSessionQueueWithCreateMethodCall:(FlutterMethodCall *)createMethodCall
                                                result:(FLTThreadSafeFlutterResult *)result {
  dispatch_async(self.captureSessionQueue, ^{
    NSString *cameraName = createMethodCall.arguments[@"cameraName"];
    NSString *resolutionPreset = createMethodCall.arguments[@"resolutionPreset"];
    NSNumber *enableAudio = createMethodCall.arguments[@"enableAudio"];
    NSError *error;
    FLTCam *cam = [[FLTCam alloc] initWithCameraName:cameraName
                                    resolutionPreset:resolutionPreset
                                         enableAudio:[enableAudio boolValue]
                                         orientation:[[UIDevice currentDevice] orientation]
                                 captureSessionQueue:self.captureSessionQueue
                                               error:&error];

    if (error) {
      [result sendError:error];
    } else {
      if (self.camera) {
        [self.camera close];
      }
      self.camera = cam;
      [self.registry registerTexture:cam
                          completion:^(int64_t textureId) {
                            [result sendSuccessWithData:@{
                              @"cameraId" : @(textureId),
                            }];
                          }];
    }
  });
}

@end