iOS開發(fā)技巧之自定義相機

更新時間：2022年07月20日 15:29:27 作者：VKOOY

這篇文章主要為大家詳細介紹了iOS開發(fā)技巧之自定義相機，文中示例代碼介紹的非常詳細，具有一定的參考價值，感興趣的小伙伴們可以參考一下

最近公司的項目中用到了相機，由于不用系統的相機，UI給的相機切圖，必須自定義才可以。就花時間簡單研究了一下相機的自定義。

相機屬于系統硬件，這就需要我們來手動調用iPhone的相機硬件，分為以下步驟：

1、首先聲明以下對象

#import <AVFoundation/AVFoundation.h>
//捕獲設備，通常是前置攝像頭，后置攝像頭，麥克風（音頻輸入）
@property (nonatomic, strong) AVCaptureDevice *device;
 
//AVCaptureDeviceInput 代表輸入設備，他使用AVCaptureDevice 來初始化
@property (nonatomic, strong) AVCaptureDeviceInput *input;
 
//輸出圖片
@property (nonatomic ,strong) AVCaptureStillImageOutput *imageOutput;
 
//session：由他把輸入輸出結合在一起，并開始啟動捕獲設備（攝像頭）
@property (nonatomic, strong) AVCaptureSession *session;
 
//圖像預覽層，實時顯示捕獲的圖像
@property (nonatomic ,strong) AVCaptureVideoPreviewLayer *previewLayer;

2、初始化各個對象

- (void)cameraDistrict
{
// AVCaptureDevicePositionBack 后置攝像頭
// AVCaptureDevicePositionFront 前置攝像頭
 self.device = [self cameraWithPosition:AVCaptureDevicePositionFront];
 self.input = [[AVCaptureDeviceInput alloc] initWithDevice:self.device error:nil];
 
 self.imageOutput = [[AVCaptureStillImageOutput alloc] init];
 
 self.session = [[AVCaptureSession alloc] init];
 //  拿到的圖像的大小可以自行設定
 // AVCaptureSessionPreset320x240
 // AVCaptureSessionPreset352x288
 // AVCaptureSessionPreset640x480
 // AVCaptureSessionPreset960x540
 // AVCaptureSessionPreset1280x720
 // AVCaptureSessionPreset1920x1080
 // AVCaptureSessionPreset3840x2160
 self.session.sessionPreset = AVCaptureSessionPreset640x480;
 //輸入輸出設備結合
 if ([self.session canAddInput:self.input]) {
  [self.session addInput:self.input];
 }
 if ([self.session canAddOutput:self.imageOutput]) {
  [self.session addOutput:self.imageOutput];
 }
 //預覽層的生成
 self.previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.session];
 self.previewLayer.frame = CGRectMake(0, 64, SCREEN_WIDTH, SCREEN_HEIGHT-64);
 self.previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
 [self.view.layer addSublayer:self.previewLayer];
 //設備取景開始
 [self.session startRunning];
 if ([_device lockForConfiguration:nil]) {
 //自動閃光燈，
  if ([_device isFlashModeSupported:AVCaptureFlashModeAuto]) {
   [_device setFlashMode:AVCaptureFlashModeAuto];
  }
  //自動白平衡,但是好像一直都進不去
  if ([_device isWhiteBalanceModeSupported:AVCaptureWhiteBalanceModeAutoWhiteBalance]) {
   [_device setWhiteBalanceMode:AVCaptureWhiteBalanceModeAutoWhiteBalance];
  }
  [_device unlockForConfiguration];
 }
 
}

根據前后置位置拿到相應的攝像頭：

- (AVCaptureDevice *)cameraWithPosition:(AVCaptureDevicePosition)position{
 NSArray *devices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
 for ( AVCaptureDevice *device in devices )
  if ( device.position == position ){
   return device;
  }
 return nil;
}

3、拍照拿到相應圖片：

- (void)photoBtnDidClick
{
 AVCaptureConnection *conntion = [self.imageOutput connectionWithMediaType:AVMediaTypeVideo];
  if (!conntion) {
   NSLog(@"拍照失敗!");
   return;
   }
 [self.imageOutput captureStillImageAsynchronouslyFromConnection:conntion completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) {
  if (imageDataSampleBuffer == nil) {
   return ;
   }
  NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];
  self.image = [UIImage imageWithData:imageData];
  [self.session stopRunning];
  [self.view addSubview:self.cameraImageView];
}

4、保存照片到相冊：

#pragma - 保存至相冊
- (void)saveImageToPhotoAlbum:(UIImage*)savedImage
{
 
 UIImageWriteToSavedPhotosAlbum(savedImage, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);
 
}
// 指定回調方法
 
- (void)image: (UIImage *) image didFinishSavingWithError: (NSError *) error contextInfo: (void *) contextInfo
 
{
 NSString *msg = nil ;
 if(error != NULL){
  msg = @"保存圖片失敗" ;
 }else{
  msg = @"保存圖片成功" ;
 }
 UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"保存圖片結果提示"
           message:msg
           delegate:self
           cancelButtonTitle:@"確定"
           otherButtonTitles:nil];
 [alert show];
}

5、前后置攝像頭的切換

- (void)changeCamera{
 NSUInteger cameraCount = [[AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo] count];
 if (cameraCount > 1) {
  NSError *error;
  //給攝像頭的切換添加翻轉動畫
  CATransition *animation = [CATransition animation]；
  animation.duration = .5f；
  animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
  animation.type = @"oglFlip";
 
  AVCaptureDevice *newCamera = nil;
  AVCaptureDeviceInput *newInput = nil;
 //拿到另外一個攝像頭位置
  AVCaptureDevicePosition position = [[_input device] position];
  if (position == AVCaptureDevicePositionFront){
   newCamera = [self cameraWithPosition:AVCaptureDevicePositionBack];
   animation.subtype = kCATransitionFromLeft;//動畫翻轉方向
  }
  else {
   newCamera = [self cameraWithPosition:AVCaptureDevicePositionFront];
   animation.subtype = kCATransitionFromRight;//動畫翻轉方向
  }
  //生成新的輸入
  newInput = [AVCaptureDeviceInput deviceInputWithDevice:newCamera error:nil];
  [self.previewLayer addAnimation:animation forKey:nil];
  if (newInput != nil) {
   [self.session beginConfiguration];
   [self.session removeInput:self.input];
   if ([self.session canAddInput:newInput]) {
    [self.session addInput:newInput];
    self.input = newInput;
 
   } else {
    [self.session addInput:self.input];
   }
   [self.session commitConfiguration];
 
  } else if (error) {
   NSLog(@"toggle carema failed, error = %@", error);
  }
 }
}

6、相機的其它參數設置

//AVCaptureFlashMode 閃光燈
//AVCaptureFocusMode 對焦
//AVCaptureExposureMode 曝光
//AVCaptureWhiteBalanceMode 白平衡
//閃光燈和白平衡可以在生成相機時候設置
//曝光要根據對焦點的光線狀況而決定,所以和對焦一塊寫
//point為點擊的位置
- (void)focusAtPoint:(CGPoint)point{
 CGSize size = self.view.bounds.size;
 CGPoint focusPoint = CGPointMake( point.y /size.height ,1-point.x/size.width );
 NSError *error;
 if ([self.device lockForConfiguration:&error]) {
  //對焦模式和對焦點
  if ([self.device isFocusModeSupported:AVCaptureFocusModeAutoFocus]) {
   [self.device setFocusPointOfInterest:focusPoint];
   [self.device setFocusMode:AVCaptureFocusModeAutoFocus];
  }
  //曝光模式和曝光點
  if ([self.device isExposureModeSupported:AVCaptureExposureModeAutoExpose ]) {
   [self.device setExposurePointOfInterest:focusPoint];
   [self.device setExposureMode:AVCaptureExposureModeAutoExpose];
  }
 
  [self.device unlockForConfiguration];
  //設置對焦動畫
  _focusView.center = point;
  _focusView.hidden = NO;
  [UIView animateWithDuration:0.3 animations:^{
   _focusView.transform = CGAffineTransformMakeScale(1.25, 1.25);
  }completion:^(BOOL finished) {
   [UIView animateWithDuration:0.5 animations:^{
    _focusView.transform = CGAffineTransformIdentity;
   } completion:^(BOOL finished) {
    _focusView.hidden = YES;
   }];
  }];
 }
 
}

7、遇到的一些坑和解決辦法

1) 前后置攝像頭的切換

前后值不能切換，各種嘗試找了半天沒找到有原因。后來發(fā)現我在設置圖片尺寸的時候設置為1080P [self.session canSetSessionPreset: AVCaptureSessionPreset1920x1080] ，前置攝像頭并不支持這么大的尺寸，所以就不能切換前置攝像頭。我驗證了下前置攝像頭最高支持720P,720P以內可自由切換?！　?/p>

當然也可以在前后置攝像頭切換的時候，根據前后攝像頭來設置不同的尺寸，這里不在贅述。

2）焦點位置

CGPoint focusPoint = CGPointMake( point.y /size.height ,1-point.x/size.width );
setExposurePointOfInterest：focusPoint 函數后面Point取值范圍是取景框左上角（0，0）到取景框右下角（1，1）之間。官方是這么寫的：

　　The value of this property is a CGPoint that determines the receiver's focus point of interest, if it has one. A value of (0,0) indicates that the camera should focus on the top left corner of the image, while a value of (1,1) indicates that it should focus on the bottom right. The default value is (0.5,0.5).

我也試了按這個來但位置就是不對，只能按上面的寫法才可以。前面是點擊位置的y/PreviewLayer的高度，后面是1-點擊位置的x/PreviewLayer的寬度

3）對焦和曝光

我在設置對焦是先設置了模式setFocusMode，后設置對焦位置，就會導致很奇怪的現象，對焦位置是你上次點擊的位置。所以一定要先設置位置，再設置對焦模式。
曝光同上

8、寫在最后

附上demo：photographDemo

常用到的基本就這么多，寫的并不完善，有什么不對的，歡迎大家批評指正，共同學習。

以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持腳本之家。

您可能感興趣的文章: