iOS小技能：自定义相机（基础知识储备）

原创

#公众号：iOS逆向 2023-05-03 03:34:42 ©著作权

©著作权归作者所有：来自51CTO博客作者#公众号：iOS逆向的原创作品，请联系作者获取转载授权，否则将追究法律责任

引言

iOS小技能：自定义相机（基础知识储备）_CMS

I 常用基础功能

1.1模拟拍照动作

//振动，颤动，摆动
            AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);//            // 播放一下“拍照”的声音，模拟拍照            AudioServicesPlaySystemSound(1108);

1.2 能否切换前置后置

// 
- (BOOL)canSwitchCameras {
    return [[AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo] count] > 1;

}

1.3 从输出的元数据中捕捉人脸

实现输出流的代理AVCaptureMetadataOutputObjectsDelegate

_metadataOutput = [[AVCaptureMetadataOutput alloc]init];

        [_metadataOutput setMetadataObjectsDelegate:self queue:self.queue];
                [self.videoDataOutput setSampleBufferDelegate:nil queue:self.queue];

// 检测人脸是为了获得“人脸区域”，做“人脸区域”与“身份证人像框”的区域对比，当前者在后者范围内的时候，才能截取到完整的身份证图像
-(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection{
    if (metadataObjects.count) {
        AVMetadataMachineReadableCodeObject *metadataObject = metadataObjects.firstObject;

        AVMetadataObject *transformedMetadataObject = [self.previewLayer transformedMetadataObjectForMetadataObject:metadataObject];
        CGRect faceRegion = transformedMetadataObject.bounds;

        if (metadataObject.type == AVMetadataObjectTypeFace) {
            NSLog(@"是否包含头像：%d, facePathRect: %@, faceRegion: %@",CGRectContainsRect(self.faceDetectionFrame, faceRegion),NSStringFromCGRect(self.faceDetectionFrame),NSStringFromCGRect(faceRegion));

            if (CGRectContainsRect(self.faceDetectionFrame, faceRegion)) {// 只有当人脸区域的确在小框内时，才再去做捕获此时的这一帧图像
                // 为videoDataOutput设置代理，程序就会自动调用下面的代理方法，捕获每一帧图像
                if (!self.videoDataOutput.sampleBufferDelegate) {
                    [self.videoDataOutput setSampleBufferDelegate:self queue:self.queue];
                }
            }
        }
    }
}

1.4 捕获每一帧图像： AVCaptureVideoDataOutputSampleBufferDelegate

甚至代理

_videoDataOutput = [[AVCaptureVideoDataOutput alloc] init];

                    [self.videoDataOutput setSampleBufferDelegate:self queue:self.queue];

从输出的数据流捕捉单一的图像帧

#pragma mark - AVCaptureVideoDataOutputSampleBufferDelegate
#pragma mark 从输出的数据流捕捉单一的图像帧
// AVCaptureVideoDataOutput获取实时图像，这个代理方法的回调频率很快，几乎与手机屏幕的刷新频率一样快
-(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection {
    if ([self.outPutSetting isEqualToNumber:[NSNumber numberWithInt:kCVPixelFormatType_420YpCbCr8BiPlanarVideoRange]] || [self.outPutSetting isEqualToNumber:[NSNumber numberWithInt:kCVPixelFormatType_420YpCbCr8BiPlanarFullRange]]) {
        CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);

        if ([captureOutput isEqual:self.videoDataOutput]) {
            // 身份证信息识别 +(void)iDCardRecognit:(CVImageBufferRef)imageBuffer WithstopRunningBlcok:(void(^)(id make)) stopRunningBlcok finishBlock:(k_finishBlock)finishBlock;
            __weak __typeof__(self) weakSelf = self;

            [KNScanCardManage iDCardRecognit:imageBuffer  WithstopRunningBlcok:^(id  _Nonnull sender) {

                            if ([weakSelf.session isRunning]) {
                                [weakSelf.session stopRunning];
                            }

            } finishBlock:weakSelf.finishBlock];//imageBuffer






            // 身份证信息识别完毕后，就将videoDataOutput的代理去掉，防止频繁调用AVCaptureVideoDataOutputSampleBufferDelegate方法而引起的“混乱”
            if (self.videoDataOutput.sampleBufferDelegate) {
                [self.videoDataOutput setSampleBufferDelegate:nil queue:self.queue];
            }
        }
    } else {
        NSLog(@"输出格式不支持");
    }
}

1.5 点击屏幕对焦：聚焦

监听点击事件

UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc]initWithTarget:self action:@selector(focusGesture:)];
    [self.view addGestureRecognizer:tapGesture];

点击屏幕对焦

#pragma mark - 点击屏幕对焦：聚焦
- (void)focusGesture:(UITapGestureRecognizer*)gesture{
    CGPoint point = [gesture locationInView:gesture.view];
    [self focusAtPoint:point];
}
- (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]) {

        if ([self.device isFocusModeSupported:AVCaptureFocusModeAutoFocus]) {
            [self.device setFocusPointOfInterest:focusPoint];
            [self.device setFocusMode:AVCaptureFocusModeAutoFocus];
        }

        if ([self.device isExposureModeSupported:AVCaptureExposureModeAutoExpose ]) {
            [self.device setExposurePointOfInterest:focusPoint];
            [self.device setExposureMode:AVCaptureExposureModeAutoExpose];
        }

        [self.device unlockForConfiguration];
        self.focusView.center = point;
        _focusView.hidden = NO;

        //        self.focusView.alpha = 1;
        [UIView animateWithDuration:0.2 animations:^{
            self.focusView.transform = CGAffineTransformMakeScale(1.25f, 1.25f);
        } completion:^(BOOL finished) {
            [UIView animateWithDuration:0.3 animations:^{
                self.focusView.transform = CGAffineTransformMakeScale(1.0f, 1.0f);
            } completion:^(BOOL finished) {
                [self hiddenFocusAnimation];
            }];
        }];
    }

}
- (void)hiddenFocusAnimation{
    [UIView beginAnimations:nil context:UIGraphicsGetCurrentContext()];

    [UIView setAnimationDelay:3];
    self.focusView.alpha = 0;
    [UIView setAnimationDuration:0.5f];//动画时间
    [UIView commitAnimations];

}
- (void)hiddenFoucsView{
    self.focusView.alpha = !self.focusView.alpha;
}


- (void)focusDidFinsh{
    self.focusView.hidden = YES;
    self.focusView.transform = CGAffineTransformMakeScale(1.0f, 1.0f);
}

- (void)startFocusAnimation{
    self.focusView.hidden = NO;
    self.focusView.transform = CGAffineTransformMakeScale(1.25f, 1.25f);//将要显示的view按照正常比例显示出来
    [UIView beginAnimations:nil context:UIGraphicsGetCurrentContext()];

    [UIView setAnimationDidStopSelector:@selector(hiddenFocusAnimation)];
    [UIView setAnimationDuration:0.5f];//动画时间
    self.focusView.transform = CGAffineTransformIdentity;//先让要显示的view最小直至消失
    [UIView commitAnimations]; //启动动画
    //相反如果想要从小到大的显示效果，则将比例调换

}

初始化对焦区域

#pragma mark - 初始化对焦区域
-(UIImageView *)focusView{
    if (_focusView == nil) {
        _focusView = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 80, 80)];
        _focusView.backgroundColor = [UIColor clearColor];
//        _focusView.image = [UIImage imageNamed:@"foucs80pt"];
        _focusView.hidden = YES;
        [self.view addSubview:self.focusView];

    }
    return _focusView;
}

新增【触摸屏幕对焦】提示语

//  
- (UILabel *)tip4focusLabel {

    if (_tip4focusLabel == nil) {

        UILabel *tmp =[UILabel new];


        _tip4focusLabel =tmp;


        tmp.textColor = [UIColor whiteColor];
        tmp.numberOfLines = 0;
        tmp.textAlignment = NSTextAlignmentCenter;
        tmp.font = kPingFangFont(16);


        NSMutableAttributedString *xx  = [[NSMutableAttributedString alloc]init];

        xx.kn_addString(@" 触摸屏幕对焦").kn_fontColor(rgb(255,255,255)).kn_addString(@"").kn_fontColor(rgb(225,66,66)).kn_addString(@"").kn_fontColor(rgb(255,255,255));







        tmp.attributedText = xx;

        tmp.transform = CGAffineTransformMakeRotation(M_PI/2);


        [self.view addSubview:tmp];


        __weak __typeof__(self) weakSelf = self;


        [tmp mas_makeConstraints:^(MASConstraintMaker *make) {


            make.centerX.equalTo(weakSelf.view.mas_left).offset(kAdjustRatio( 23));



            make.centerY.offset(kAdjustRatio(0));


        }];





    }

    return _tip4focusLabel;
}

1.6 身份证和人头像的宽高比

身份证的宽高比

CGFloat width = iPhone5or5cor5sorSE? 240: (iPhone6or6sor7? 270: 300);
    _IDCardScanningWindowLayer.bounds = (CGRect){CGPointZero, {width, width * 1.574}};

人头像的宽高比

CGFloat facePathWidth = iPhone5or5cor5sorSE? 125: (iPhone6or6sor7? 150: 180);
    CGFloat facePathHeight = facePathWidth * 0.812;

1.7 调整屏幕亮度

常用场景我们可以在打开某个特定界面的时候调整亮度，退出时恢复亮度！

类似支付宝微信的二维码提供扫描时会使屏幕高亮状态

//获取当前屏幕的亮度
CGFloat value = [UIScreen mainScreen].brightness;

//设置屏幕亮度
//设置窗口亮度大小 范围是0.1 -1.0
[[UIScreen mainScreen] setBrightness:0.5];

//设置屏幕常亮
//设置屏幕常亮
[UIApplication sharedApplication].idleTimerDisabled = YES;

//恢复屏幕默认
　　[UIApplication sharedApplication].idleTimerDisabled = NO;

1.8 获取iPhone设备摄像头所感知的环境光强度

值越大，光强度效果越明显

使用场景：自定义相机进行OCR的时候，检测到光强度暗的时候，提示打开闪光灯(或者光线暗的时候，能够自动打开闪光灯)

#import <ImageIO/ImageIO.h>
-  (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{
    CFDictionaryRef metadataDict = CMCopyDictionaryOfAttachments(NULL,sampleBuffer, kCMAttachmentMode_ShouldPropagate);
    NSDictionary *metadata = [[NSMutableDictionary alloc] initWithDictionary:(__bridge NSDictionary*)metadataDict];
    CFRelease(metadataDict);
    NSDictionary *exifMetadata = [[metadata objectForKey:(NSString *)kCGImagePropertyExifDictionary] mutableCopy];
    float brightnessValue = [[exifMetadata objectForKey:(NSString *)kCGImagePropertyExifBrightnessValue] floatValue];

   NSLog(@"%f",brightnessValue);
    if (self.delegate && [self.delegate respondsToSelector:@selector(QRCodeScanManager:brightnessValue:)]) {
        [self.delegate QRCodeScanManager:self brightnessValue:brightnessValue];
    }

}

根据光线强弱值打开手电筒的方法

/** 根据光线强弱值打开手电筒的方法 (brightnessValue: 光线强弱值) */
- (void)QRCodeScanManager:(SGQRCodeScanManager *)scanManager brightnessValue:(CGFloat)brightnessValue;

光线明亮，隐藏闪光灯按钮;光线昏暗，显示闪光灯按钮

if (brightness > 0) {
        // 光线明亮，隐藏按钮
        [self.maskView hideLightButton];
    } else {
        // 光线昏暗，显示按钮
        [self.maskView showLightButton];
    }

1.9 手电筒

定义属性

/** 手电筒 */
@property (nonatomic, strong) UIButton * flashlight;

初始化手电筒

//
    CGFloat flashlight_width = 40;
    CGFloat flashlight_height = 40;

    self.flashlight = [UIButton buttonWithType:UIButtonTypeCustom];
    self.flashlight.frame = CGRectMake(0, 0, flashlight_width, flashlight_height);
    //icon_shoukuan_shoudian_p
    [self.flashlight setImage:[UIImage imageNamed:@"icon_shoukuan_shoudian"] forState:UIControlStateNormal];
    [self.flashlight addTarget:self action:@selector(flashlightAction:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:self.flashlight];

处理打开关闭手电筒动作flashlightAction

#pragma mark - 打开/关闭 手电筒

- (void)flashlightAction:(UIButton *)sender{
    sender.selected = !sender.selected;
    if (sender.selected) {
        [sender setImage:[UIImage imageNamed:@"icon_shoukuan_shoudian_p"] forState:UIControlStateSelected];
        self.flashlightHintLabel.textColor = ZFColor(133, 235, 0, 1);

        //打开闪光灯
        AVCaptureDevice *captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
        NSError *error = nil;

        if ([captureDevice hasTorch]) {
            BOOL locked = [captureDevice lockForConfiguration:&error];//请求独占访问硬件设备
            if (locked) {
                captureDevice.torchMode = AVCaptureTorchModeOn;
                [captureDevice unlockForConfiguration];// 请求解除独占访问硬件设备
            }
        }

    }else{
        [sender setImage:[UIImage imageNamed:@"icon_shoukuan_shoudian"] forState:UIControlStateSelected];
        self.flashlightHintLabel.textColor = ZFWhite;

        //关闭闪光灯
        AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
        if ([device hasTorch]) {
            [device lockForConfiguration:nil];
            [device setTorchMode: AVCaptureTorchModeOff];
            [device unlockForConfiguration];
        }
    }
}

II 常用视图

2.1 扫描线

2.1.1 采用动画组进行实现

扫描线控件

UIImage * scanLine = [UIImage imageNamed:@"img_shoukuan_red"];



    self.scanLineImg = [[UIImageView alloc] init];
    self.scanLineImg.image = scanLine;
    self.scanLineImg.contentMode = UIViewContentModeScaleAspectFit;
    [self addSubview:self.scanLineImg];
    [self.scanLineImg.layer addAnimation:[self animation] forKey:nil];

动画

/**
 *  动画
 */
- (CABasicAnimation *)animation{
    CABasicAnimation * animation = [CABasicAnimation animationWithKeyPath:@"position"];
    animation.duration = 3;
    animation.fillMode = kCAFillModeForwards;
    animation.removedOnCompletion = NO;
    animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
    animation.repeatCount = MAXFLOAT;

    //第一次旋转
    if (_isFirstTransition) {
        //横屏
        if ([[UIApplication sharedApplication] statusBarOrientation] == UIInterfaceOrientationLandscapeLeft || [[UIApplication sharedApplication] statusBarOrientation] == UIInterfaceOrientationLandscapeRight){

            animation.fromValue = [NSValue valueWithCGPoint:CGPointMake(self.center.x, (self.center.y - self.frame.size.height * ZFScanRatio * 0.3 + self.scanLineImg.image.size.height * 0.3))];
            animation.toValue = [NSValue valueWithCGPoint:CGPointMake(self.center.x, (self.center.y + self.frame.size.height * ZFScanRatio * 0.3 - self.scanLineImg.image.size.height * 0.3))];

        //竖屏
        }else{



            animation.toValue = [NSValue valueWithCGPoint:CGPointMake(self.center.x, self.center.y + self.frame.size.width * ZFScanRatio * 0.1 - self.scanLineImg.image.size.height * 0.5)];

            animation.fromValue = [NSValue valueWithCGPoint:CGPointMake(self.center.x,self.center.y + self.frame.size.width * ZFScanRatio * 0.1  -self.frame.size.width * ZFScanRatio *0.9      )];


            //

//            animation.fromValue = [NSValue valueWithCGPoint:CGPointMake(self.center.x, (self.topLeftImg.y))];
//            animation.toValue = [NSValue valueWithCGPoint:CGPointMake(self.center.x, self.bottomLeftImg.y)];





        }

        _isFirstTransition = NO;

        //非第一次旋转
    }else{
        //横屏
        if ([[UIApplication sharedApplication] statusBarOrientation] == UIInterfaceOrientationLandscapeLeft || [[UIApplication sharedApplication] statusBarOrientation] == UIInterfaceOrientationLandscapeRight){

            animation.fromValue = [NSValue valueWithCGPoint:CGPointMake(self.center.x, (self.frame.size.height - (self.frame.size.width * ZFScanRatio)) * 0.3)];
            animation.toValue = [NSValue valueWithCGPoint:CGPointMake(self.center.x, self.scanLineImg.frame.origin.y + self.frame.size.width * ZFScanRatio - self.scanLineImg.frame.size.height * 0.3)];


            //竖屏
        }else{

            animation.fromValue = [NSValue valueWithCGPoint:CGPointMake(self.center.x, (self.frame.size.height - (self.frame.size.height * ZFScanRatio)) * 0.3)];
            animation.toValue = [NSValue valueWithCGPoint:CGPointMake(self.center.x, self.scanLineImg.frame.origin.y + self.frame.size.height * ZFScanRatio - self.scanLineImg.frame.size.height * 0.3)];
        }
    }

    return animation;
}

移除动画

/**
 *  移除动画
 */
- (void)removeAnimation{
    [self.scanLineImg.layer removeAllAnimations];
}

设置扫描线frame

//CGFloat const ZFScanRatio = 0.68f;

        self.scanLineImg.frame = CGRectMake((self.frame.size.width - (self.frame.size.width * ZFScanRatio)) * 0.5,

                                            (self.frame.size.height - (self.frame.size.width * ZFScanRatio)) * tmp3,


                                            self.frame.size.width * ZFScanRatio, scanLine.size.height);

2.1.2 定时调用setNeedsDisplay定时redrawn，来实现实现水平扫描线

使用定时器进行实现水平扫描线

调用setNeedsDisplay定时redrawn

#pragma mark - 添加定时器
-(void)addTimer {
    _timer = [NSTimer scheduledTimerWithTimeInterval:0.02 target:self selector:@selector(timerFire:) userInfo:nil repeats:YES];
    [_timer fire];
}

-(void)timerFire:(id)notice {
    [self setNeedsDisplay];//Marks the receiver’s entire bounds rectangle as needing to be redrawn.
}

-(void)dealloc {
    [_timer invalidate];
}

- (void)drawRect:(CGRect)rect {
    rect = _IDCardScanningWindowLayer.frame;

    // 人像提示框
//    UIBezierPath *facePath = [UIBezierPath bezierPathWithRect:_facePathRect];
//    facePath.lineWidth = 1.5;
//    [[UIColor whiteColor] set];
//    [facePath stroke];

    // 水平扫描线
    CGContextRef context = UIGraphicsGetCurrentContext();

    static CGFloat moveX = 0;
    static CGFloat distanceX = 0;

    CGContextBeginPath(context);
    CGContextSetLineWidth(context, 2);
    CGContextSetRGBStrokeColor(context,0.3,0.8,0.3,0.8);
    CGPoint p1, p2;// p1, p2 连成水平扫描线;

    moveX += distanceX;
    if (moveX >= CGRectGetWidth(rect) - 2) {
        distanceX = -2;
    } else if (moveX <= 2){
        distanceX = 2;
    }

    p1 = CGPointMake(CGRectGetMaxX(rect) - moveX, rect.origin.y);
    p2 = CGPointMake(CGRectGetMaxX(rect) - moveX, rect.origin.y + rect.size.height);

    CGContextMoveToPoint(context,p1.x, p1.y);
    CGContextAddLineToPoint(context, p2.x, p2.y);

    /*
     // 竖直扫描线
     static CGFloat moveY = 0;
     static CGFloat distanceY = 0;
     CGPoint p3, p4;// p3, p4连成竖直扫描线

     moveY += distanceY;
     if (moveY >= CGRectGetHeight(rect) - 2) {
     distanceY = -2;
     } else if (moveY <= 2) {
     distanceY = 2;
     }
     p3 = CGPointMake(rect.origin.x, rect.origin.y + moveY);
     p4 = CGPointMake(rect.origin.x + rect.size.width, rect.origin.y + moveY);

     CGContextMoveToPoint(context,p3.x, p3.y);
     CGContextAddLineToPoint(context, p4.x, p4.y);
     */

    CGContextStrokePath(context);
}

2.2 iOS13适配【present 半屏问题】

自定义相机推荐模态展示，并且modalPresentationStyle设置为全屏UIModalPresentationFullScreen

iOS13适配【present 半屏问题】如果没适配会导致列表下拉刷新失效

modalPresentationStyle属性默认不是UIModalPresentationFullScreen了，需要根据需求手动设置。

- (void)K_presentViewController:(UIViewController *)viewControllerToPresent animated:(BOOL)flag completion:(void (^)(void))completion {
    if (@available(iOS 13.0, *)) {
        if (viewControllerToPresent.K_automaticallySetModalPresentationStyle) {
            viewControllerToPresent.modalPresentationStyle = UIModalPresentationFullScreen;
        }
        [self K_presentViewController:viewControllerToPresent animated:flag completion:completion];
    } else {
        // Fallback on earlier versions
        [self K_presentViewController:viewControllerToPresent animated:flag completion:completion];
    }
}

iOS13适配:灵活控制模态展示的视图样式（全屏/下滑返回）文中提供完整demo源码