iOS 扫描二维码自动打开灯 检测环境光线强度

扫描二维码自动打开灯 检测环境光线强度，做的不太好，打开灯了没有关闭，后期优化可以打开关闭的代码，并且加一个定时器时间间隔（例如10秒左右）来控制是否改变灯的状态，否则灯会随着光线闪来闪去的。最简单 的也可以价格灯光的按钮，点击打开就OK了，省的麻烦。

目前没有做到扫描时自动拉近镜头，个人猜想，微信等用的是自己的API, 封装的matlab，matlab里有识别范围的确定时机。 可以在距离远的时候，根据识别范围里的二维码大小来拉近焦距。

以上说的仅仅是猜想。。。。大神请过。

#import "ExScanViewController.h"

#import "EXScanHelper.h"

#import "ExScanHelperView.h"

#import <AVFoundation/AVFoundation.h>

#import <ImageIO/ImageIO.h>

@interface ExScanViewController ()<AVCaptureMetadataOutputObjectsDelegate,AVCaptureVideoDataOutputSampleBufferDelegate>{

    AVCaptureSession * session;//输入输出的中间桥梁

    NSString *scanMessage;

    BOOL isRequesting;

    float oriX_scan;

    float oriY_scan;

    float height_scan;

    float width_scan;

}

@property (nonatomic,strong) UIView          *lineView;//扫描线

@end

@implementation ExScanViewController

@synthesize delegate;

- (void)viewDidLoad {

    [super viewDidLoad];

    self.title = @"二维码";

    [self instanceDevice];

    

}

/**

 *  配置相机属性

 */

- (void)instanceDevice{

    oriX_scan = self.view.frame.size.width * 0.2;

    oriY_scan = self.view.frame.size.width * 0.2 + 40;

    height_scan = self.view.frame.size.width * 0.6;

    width_scan = SCREEN_WIDTH - oriX_scan * 2;

    

    AVCaptureDevice * device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

    AVCaptureDeviceInput * input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];

    

    //扫码

    AVCaptureMetadataOutput * output = [[AVCaptureMetadataOutput alloc]init];

    

    CGRect rectInterest = CGRectMake((oriY_scan - 20) / SCREEN_HEIGHT,(oriX_scan - 10 )/ SCREEN_WIDTH,(height_scan + 40) / SCREEN_HEIGHT,(width_scan + 20) / SCREEN_WIDTH);

    [output setRectOfInterest:rectInterest];

    [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];

    session = [[AVCaptureSession alloc]init];

    [session setSessionPreset:AVCaptureSessionPresetHigh];

    

    

    AVCaptureVideoDataOutput *lightOutput = [[AVCaptureVideoDataOutput alloc] init];

    [lightOutput setSampleBufferDelegate:self queue:dispatch_get_main_queue()];

    

    if (input) {

        [session addInput:input];

    }

    

    if (output) {

        //扫码输出

        [session addOutput:output];

        [session addOutput:lightOutput];

        

        NSMutableArray *a = [[NSMutableArray alloc] init];

        if ([output.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeQRCode]) {

            [a addObject:AVMetadataObjectTypeQRCode];

        }

        if ([output.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeEAN13Code]) {

            [a addObject:AVMetadataObjectTypeEAN13Code];

        }

        if ([output.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeEAN8Code]) {

            [a addObject:AVMetadataObjectTypeEAN8Code];

        }

        if ([output.availableMetadataObjectTypes containsObject:AVMetadataObjectTypeCode128Code]) {

            [a addObject:AVMetadataObjectTypeCode128Code];

        }

        output.metadataObjectTypes=a;

    }

    

    AVCaptureVideoPreviewLayer * layer = [AVCaptureVideoPreviewLayer layerWithSession:session];

    layer.videoGravity=AVLayerVideoGravityResizeAspectFill;

    layer.frame = self.view.layer.bounds;

    [self.view.layer insertSublayer:layer atIndex:0];

    

    [self setOverlayPickerView];

    

    [session addObserver:self forKeyPath:@"running" options:NSKeyValueObservingOptionNew context:nil];

    

    [session startRunning];

    

}

/**

 *  监听扫码状态-修改扫描动画

 */

- (void)observeValueForKeyPath:(NSString *)keyPath

                      ofObject:(id)object

                        change:(NSDictionary *)change

                       context:(void *)context{

    

    if ([object isKindOfClass:[AVCaptureSession class]]) {

        BOOL isRunning = ((AVCaptureSession *)object).isRunning;

        if (isRunning) {

            [self addAnimation];

        }else{

            [self removeAnimation];

        }

    }

}

/**

 *  获取扫码结果

 */

-(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection{

    if (metadataObjects.count>0) {

        

        [self stopRunning];

        

        AVMetadataMachineReadableCodeObject * metadataObject = [metadataObjects objectAtIndex :0];

        

        //输出扫描字符串

        NSString *data = metadataObject.stringValue;

        

        if (data) {

            scanMessage = data;

            

            //delegate

            if(delegate &&[delegate respondsToSelector:@selector(getScanDataString:)]){

                [self.navigationController popViewControllerAnimated:YES];

                [delegate getScanDataString:scanMessage];

            }

            

            //block

            if (self.block_scan) {

                [self.navigationController popViewControllerAnimated:YES];

                self.block_scan(scanMessage);

            }

            NSLog(@"%@",scanMessage);

        }

    }

}

/**

 *  创建扫码页面

 */

- (void)setOverlayPickerView

{

    

    self.view.backgroundColor = [UIColor whiteColor];

    ExScanHelperView *view = [[ExScanHelperView alloc]initWithFrame:CGRectMake(0, 0, SCREEN_WIDTH, SCREEN_HEIGHT) ScanAreaFrame:CGRectMake(oriX_scan,oriY_scan, width_scan ,height_scan)];

    view.backgroundColor = [UIColor clearColor];

    [self.view addSubview:view];

    

    

    

    UILabel *label_content = [[UILabel alloc]initWithFrame:CGRectMake(oriX_scan, oriY_scan + height_scan + 20, SCREEN_WIDTH - 2 * oriX_scan, 40)];

    label_content.text = @"放入框内，自动扫描";

    label_content.textColor = [UIColor whiteColor];

    label_content.font = [UIFont iconFontOfSize:14];

    label_content.textAlignment = NSTextAlignmentCenter;

    [self.view addSubview:label_content];

    

    UILabel *label_content2 = [[UILabel alloc]initWithFrame:CGRectMake(oriX_scan, label_content.tz_bottom + 30, SCREEN_WIDTH - 2 * oriX_scan, 40)];

    label_content2.text = @"加为好友，才可以互抢红包";

    label_content2.textColor = [UIColor colorWithHexString:@"2F7DF1"];

    label_content2.font = [UIFont iconFontOfSize:14];

    label_content2.textAlignment = NSTextAlignmentCenter;

    [self.view addSubview:label_content2];

    

    

    //扫描线

    _lineView = [[UIView alloc]init];

    _lineView.backgroundColor = [UIColor colorWithHexString:@"2F7DF1"];

    _lineView.frame = CGRectMake(oriX_scan + 15, oriY_scan, width_scan - 30, 0.5);

    [self.view addSubview:_lineView];

    

}

/**

 *  添加扫码动画

 */

- (void)addAnimation{

    _lineView.hidden = NO;

    NSNumber *y = [NSNumber numberWithFloat:0];

    NSNumber *toY = [NSNumber numberWithFloat:height_scan - 3];

    CABasicAnimation *animation = [self moveYTime:2 fromY:y  toY:toY rep:OPEN_MAX];

    [_lineView.layer addAnimation:animation forKey:@"LineAnimation"];

}

- (CABasicAnimation *)moveYTime:(float)time fromY:(NSNumber *)fromY toY:(NSNumber *)toY rep:(int)rep{

    

    CABasicAnimation *animationMove = [CABasicAnimation animationWithKeyPath:@"transform.translation.y"];

    [animationMove setFromValue:fromY];

    [animationMove setToValue:toY];

    animationMove.duration = time;

    animationMove.delegate = self;

    animationMove.repeatCount  = rep;

    animationMove.fillMode = kCAFillModeForwards;

    animationMove.removedOnCompletion = NO;

    animationMove.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];

    return animationMove;

}

/**

 *  去除扫码动画

 */

- (void)removeAnimation{

    [_lineView.layer removeAnimationForKey:@"LineAnimation"];

    _lineView.hidden = YES;

}

/**

 *  开始扫码

 */

- (void)startRunning{

    [session startRunning];

}

/**

 *  结束扫码

 */

- (void)stopRunning{

    [session stopRunning];

}

- (void)viewWillDisappear:(BOOL)animated {

    [super viewWillDisappear:animated];

    [self stopRunning];

}

/**

 *  开启/关闭手电筒

 */

- (void)clickLightBtn:(UIButton *)sender {

    Class captureDeviceClass = NSClassFromString(@"AVCaptureDevice");

    if (captureDeviceClass != nil) {

        AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

        if ([device hasTorch] &&[device hasFlash]){

            

            [device lockForConfiguration:nil];

            if (!sender.selected) {

                [device setTorchMode:AVCaptureTorchModeOn];

                [device setFlashMode:AVCaptureFlashModeOn];

                sender.selected = YES;

            } else {

                [device setTorchMode:AVCaptureTorchModeOff];

                [device setFlashMode:AVCaptureFlashModeOff];

                sender.selected = NO;

            }

            [device unlockForConfiguration];

        }

    }

}

/**

 *  移除监听

 */

- (void)dealloc{

    [session removeObserver:self forKeyPath:@"running"];

}

#pragma mark- AVCaptureVideoDataOutputSampleBufferDelegate的方法

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection {

    Class captureDeviceClass = NSClassFromString(@"AVCaptureDevice");

    if (captureDeviceClass != nil) {

        

        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);

        

        // 根据brightnessValue的值来打开和关闭闪光灯

       AVCaptureDevice * myLightDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

        BOOL result = [myLightDevice hasTorch];//判断设备是否有闪光灯

        if ((brightnessValue < 0) && result) {//打开闪光灯

            [myLightDevice lockForConfiguration:nil];

            [myLightDevice setTorchMode: AVCaptureTorchModeOn];//开

            [myLightDevice unlockForConfiguration];

            

        }else if((brightnessValue > 0) && result) {//关闭闪光灯

            //[myLightDevice lockForConfiguration:nil];

           // [myLightDevice setTorchMode: AVCaptureTorchModeOff];

            //[myLightDevice unlockForConfiguration];

        }

    }

}

@end