iOS 使用AVFoundation 扫描二维码并限定扫描区域(带代码生成蒙版)

使用AVFoundation 生成的二维码扫描器，扫描速度快，加上扫描限定区域缩小扫描范围，另外代码直接在扫描区域外生成黑色透明蒙版，简单扫描动画。相册相片识别二维码信息（只支持ios8及以上版本）。功能写的比较简单，细节需要的自己去优化吧~详情见附件！ 
 另外：二维码生成可以参考站内其他源码：http://blog.yourtion.com/custom-cifilter-qrcode-generator.html 

#import <UIKit/UIKit.h>#import <AVFoundation/AVFoundation.h>@interface QRCodeScanController : UIViewController<AVCaptureMetadataOutputObjectsDelegate>@end

//NOTE: 二维码扫描实现。  生成二维码以及扫描二维码实现方式是基于AVFoundation库，由于Apple 在 IOS8.0后才//      提供了从相册识别二维码的新特性（代码中已被注释掉），为了兼容IOS8.0以前机型，故识别相片二维码信息采用的是开源库ZXINGObjc.//      ZBar  Zxing均已停止更新且不支持64位架构。#import "QRCodeScanController.h"#import "NSObject+GCD.h"@interface QRCodeScanController ()@property (weak, nonatomic) IBOutlet UIImageView *scanBackgrondImageView;@property (weak, nonatomic) IBOutlet UIView *scanContainerView;@property (weak, nonatomic) IBOutlet UIView *scanView;@property (weak, nonatomic) IBOutlet UILabel *statusLabel;@property(strong,nonatomic) AVCaptureSession *session; // 二维码生成的绘画@property(strong,nonatomic)  AVCaptureVideoPreviewLayer *previewLayer;@property(assign,nonatomic) BOOL finished;@property (nonatomic,strong)UIImageView * readLineView;//扫描器灰色蒙板。@property (nonatomic,strong)CALayer * maskLayer;@property(nonatomic,strong)CIDetector * detector;@property(nonatomic,assign)CMVideoDimensions dimensions;@property (nonatomic,strong) NSString * albumId;@property (weak, nonatomic) IBOutlet UILabel *remindLabel;@end@implementation QRCodeScanController- (void)dealloc{        // 删除预览图层    if (self.previewLayer) {        [self.previewLayer removeFromSuperlayer];    }    if (self.maskLayer) {        self.maskLayer.delegate = nil;    }    NSLog(@"%@ will dealloc !",NSStringFromClass([self class]));}- (void)viewDidLoad {    [super viewDidLoad];    self.navigationController.navigationBar.translucent = NO;}- (void)viewWillDisappear:(BOOL)animated{    [super viewWillDisappear:animated];    [self stopScanning:self.session];}-(void)viewWillAppear:(BOOL)animated{    [super viewWillAppear:animated];    if (!self.session) {        [self readQRcode];    }}- (void)onCancelBarButtonTouched:(id)sender{    [self dismissViewControllerAnimated:YES completion:nil];}//ios8.0及以上版本可使用。- (CIDetector *)detector{    if (_detector == nil) {        NSDictionary * options = @{CIDetectorAccuracy : CIDetectorAccuracyHigh};        _detector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:nil options:options];    }    return _detector;}- (void)doneButtonTouched:(id)sender{    if (self.finished) {        // 1. 如果扫描完成，停止会话                [self stopScanning:self.session];                // 2. 删除预览图层                [self.previewLayer removeFromSuperlayer];    }        [self dismissViewControllerAnimated:YES completion:^{            }];}- (void)setStatusText:(NSString *)text{        CGRect stringRect = [text boundingRectWithSize:CGSizeMake(self.statusLabel.frame.size.width, 80.0)                                                  options:(NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading)                                               attributes:@{ NSFontAttributeName : self.statusLabel.font }                                                  context:nil];    CGRect rect = self.statusLabel.frame;    rect.size.height = MAX(stringRect.size.height, rect.size.height);    self.statusLabel.frame = rect;    self.statusLabel.text = text;}//停止扫描- (void)stopScanning:(AVCaptureSession *)session{        [session stopRunning];    safe_dispatch_main_async(^{        [self.scanBackgrondImageView.layer removeAllAnimations];    });}//开始扫描- (void)startScanning:(AVCaptureSession *)session{    [session startRunning];    safe_dispatch_main_async(^{        if (_readLineView) {            [self.scanBackgrondImageView.layer removeAllAnimations];        }else{            [self loopDrawLine];        }    });}#pragma mark 扫描动画-(void)loopDrawLine{        CGRect screenBounds = [[UIScreen mainScreen] bounds];    CGFloat scaleX = screenBounds.size.width/320.0;    CGFloat loopLineWidth = 244.0 * scaleX;        CGRect rect = CGRectMake(0, 5, loopLineWidth, 2);    if (_readLineView) {        [_readLineView removeFromSuperview];    }    __weak QRCodeScanController *weakSelf = self;    weakSelf.readLineView = [[UIImageView alloc] initWithFrame:rect];    [_readLineView setImage:[UIImage imageNamed:@"scan_line.png"]];    [UIView animateWithDuration:1.5                          delay: 0.0                        options: UIViewAnimationOptionCurveEaseIn                     animations:^{                         //修改fream的代码写在这里                         weakSelf.readLineView.frame =CGRectMake(weakSelf.scanBackgrondImageView.frame.origin.x, weakSelf.scanBackgrondImageView.frame.origin.y+weakSelf.scanBackgrondImageView.frame.size.height - 5, loopLineWidth, 2);                         [weakSelf.readLineView setAnimationRepeatCount:0];                                              }                     completion:^(BOOL finished){                         [weakSelf loopDrawLine];                     }];        [weakSelf.scanBackgrondImageView addSubview:weakSelf.readLineView];}#pragma mark - 读取二维码- (void)readQRcode{        // 1. 摄像头设备        AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];                // 2. 设置输入        // 因为模拟器是没有摄像头的，因此在此最好做一个判断        NSError *error = nil;        AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];        if (error) {                NSLog(@"没有摄像头-%@", error.localizedDescription);                return;    }    // 3. 设置输出(Metadata元数据)        AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc] init];        // 3.1 设置输出的代理        // 说明：使用主线程队列，相应比较同步，使用其他队列，相应不同步，容易让用户产生不好的体验        [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];        // 4. 拍摄会话        //在生成拍摄回话时原来直接设置的是最高清画质，但对于ipod 5这类低配设备是不支持的，故在此我采取了下面这种方式来设置画质。    AVCaptureSession *session = [[AVCaptureSession alloc] init];    if ([device supportsAVCaptureSessionPreset:AVCaptureSessionPreset1920x1080]) {        session.sessionPreset = AVCaptureSessionPreset1920x1080;//设置图像输出质量        self.dimensions = (CMVideoDimensions){1080,1920};    }else if ([device supportsAVCaptureSessionPreset:AVCaptureSessionPreset1280x720]){        session.sessionPreset = AVCaptureSessionPreset1280x720;        self.dimensions = (CMVideoDimensions){720,1280};    }else if ([device supportsAVCaptureSessionPreset:AVCaptureSessionPreset640x480]){        session.sessionPreset = AVCaptureSessionPreset640x480;        self.dimensions = (CMVideoDimensions){480,640};    }else if ([device supportsAVCaptureSessionPreset:AVCaptureSessionPreset352x288]){        session.sessionPreset = AVCaptureSessionPreset352x288;        self.dimensions = (CMVideoDimensions){288,352};    }        // 添加session的输入和输出        [session addInput:input];        [session addOutput:output];        // 4.1 设置输出的格式        // 提示：一定要先设置会话的输出为output之后，再指定输出的元数据类型！        [output setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode]];        CGRect scanBounds = [self.view bounds];        // 5. 设置预览图层（用来让用户能够看到扫描情况）        AVCaptureVideoPreviewLayer *preview = [AVCaptureVideoPreviewLayer layerWithSession:session];        // 5.1 设置preview图层的属性        [preview setVideoGravity:AVLayerVideoGravityResizeAspectFill];        // 5.2 设置preview图层的大小        [preview setFrame:scanBounds];        preview.backgroundColor = [UIColor lightGrayColor].CGColor;        // 5.3 将图层添加到视图的图层        [self.view.layer insertSublayer:preview atIndex:0];        self.previewLayer = preview;        self.maskLayer = [[CALayer alloc]init];    self.maskLayer.frame = self.view.layer.bounds;    self.maskLayer.delegate = self;    [self.view.layer insertSublayer:self.maskLayer above:self.previewLayer];    [self.maskLayer setNeedsDisplay];            //5.4设置扫描区域        /*获取图像输出大小*/    CMVideoDimensions dimensions = self.dimensions;    CGFloat width = dimensions.width;    CGFloat height = dimensions.height;        CGSize size = scanBounds.size;        CGRect screenBounds = [[UIScreen mainScreen] bounds];    CGFloat scaleX = screenBounds.size.width/320.0;    CGFloat scaleY = screenBounds.size.height/568.0;    CGRect scanFrame = [self.view convertRect:self.scanView.frame fromView:self.scanView.superview];    CGRect cropRect = CGRectMake(scanFrame.origin.x * scaleX, scanFrame.origin.y * scaleY, scanFrame.size.width*scaleX, scanFrame.size.height * scaleY);        CGFloat p1 = size.height/size.width;    CGFloat p2 = height/width; //与之前设置的图像输出质量应该对应。    if (p1 < p2) {        CGFloat fixHeight = self.view.bounds.size.width * height / width; //缩放并剪裁后的高度。        CGFloat fixPadding = (fixHeight - size.height)/2;        output.rectOfInterest = CGRectMake((cropRect.origin.y + fixPadding)/fixHeight,                                           cropRect.origin.x/size.width,                                           cropRect.size.height/fixHeight,                                           cropRect.size.width/size.width);    } else {        CGFloat fixWidth = self.view.bounds.size.height * width / height;        CGFloat fixPadding = (fixWidth - size.width)/2;        output.rectOfInterest = CGRectMake(cropRect.origin.y/size.height,                                           (cropRect.origin.x + fixPadding)/fixWidth,                                           cropRect.size.height/size.height,                                           cropRect.size.width/fixWidth);    }    //说明: rectOfInterest 参数和普通的Rect范围不太一样，它的四个值的范围都是0-1，表示比例    //      参数里的x对应的恰恰是距离左上角的垂直距离，y对应的是距离左上角的水平距离,宽度和高度设置的情况也是类似    //      举个例子如果我们想让扫描的处理区域是屏幕的下半部分，我们这样设置  output.rectOfInterest=CGRectMake(0.5,0,0.5, 1)        // 6. 启动会话        [self startScanning:session];        self.session = session;    }#pragma mark - 输出代理方法// 此方法是在识别到QRCode，并且完成转换// 如果QRCode的内容越大，转换需要的时间就越长- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection{        // 扫描结果        if (metadataObjects.count > 0) {                AVMetadataMachineReadableCodeObject *obj = metadataObjects[0];        NSString *result = obj.stringValue;                self.remindLabel.text = [NSString stringWithFormat:@"扫描结果:%@",result];        //result 即为扫描得到的结果。        //可以开始对扫描得到的结果进行相应处理了。    }}//Note: 蒙板生成。需设置代理，并在退出页面时取消代理。-(void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx{    if (layer == self.maskLayer) {        UIGraphicsBeginImageContextWithOptions(self.maskLayer.frame.size, NO, 1.0);        CGContextSetFillColorWithColor(ctx, [UIColor colorWithRed:0 green:0 blue:0 alpha:0.6].CGColor);        CGContextFillRect(ctx, self.maskLayer.frame);        CGRect scanFrame = [self.view convertRect:self.scanView.frame fromView:self.scanView.superview];        CGContextClearRect(ctx, scanFrame);    }}@end