二维码的生成与扫描

生成二维码

1. 导入库#import <CoreImage/CoreImage.h>

2. 通过滤镜CIFilter生成二维码

- (UIImage *)createQRCode:(NSString *)code{    //1. 创建过滤器, 这里的@"CIQRCodeGenerator"是固定的    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];    //2.恢复默认设置    [filter setDefaults];    //3. 给过滤器添加数据    NSData *codeData = [code dataUsingEncoding:NSUTF8StringEncoding];    //4. 数据value必须是NSData类型的    [filter setValue:codeData forKey:@"inputMessage"];    //5. 生成二维码    CIImage *ciImg = filter.outputImage;    return [UIImage imageWithCIImage:ciImg];}

上述方法生成的二维码是模糊的, 结合一下方法可以生成高清二维码:

/** *  根据CIImage生成指定大小的UIImage * *  @param image CIImage *  @param size  图片宽度 * *  @return 生成高清的UIImage */- (UIImage *)creatNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat)size{    CGRect extent = CGRectIntegral(image.extent);    CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));    // 1. 创建bitmap    size_t width = CGRectGetWidth(extent) * scale;    size_t height = CGRectGetHeight(extent) * scale;    CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();    CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, cs, (CGBitmapInfo)kCGImageAlphaNone);    CIContext *context = [CIContext contextWithOptions:nil];    CGImageRef bitmapImage = [context createCGImage:image fromRect:extent];    CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone);    CGContextScaleCTM(bitmapRef, scale, scale);    CGContextDrawImage(bitmapRef, extent, bitmapImage);    // 2.保存bitmap图片    CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);    CGContextRelease(bitmapRef);    CGImageRelease(bitmapImage);    return [UIImage imageWithCGImage:scaledImage];}

将上述生成高清二维码的方法封装成UIImage的Category如下

.h 文件

#import <UIKit/UIKit.h>@interface UIImage (Category)/** *  根据CIImage生成指定大小的UIImage * *  @param image CIImage *  @param size  图片宽度 * *  @return 生成的高清的UIImage */+ (UIImage *)creatNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat)size;@end

.m 文件

#import "UIImage+Category.h"@implementation UIImage (Category)/** *  根据CIImage生成指定大小的UIImage * *  @param image CIImage *  @param size  图片宽度 * *  @return 生成的高清的UIImage */+ (UIImage *)creatNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat)size{    CGRect extent = CGRectIntegral(image.extent);    CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));    // 1. 创建bitmap    size_t width = CGRectGetWidth(extent) * scale;    size_t height = CGRectGetHeight(extent) * scale;    CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();    CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, cs, (CGBitmapInfo)kCGImageAlphaNone);    CIContext *context = [CIContext contextWithOptions:nil];    CGImageRef bitmapImage = [context createCGImage:image fromRect:extent];    CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone);    CGContextScaleCTM(bitmapRef, scale, scale);    CGContextDrawImage(bitmapRef, extent, bitmapImage);    // 2.保存bitmap图片    CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);    CGContextRelease(bitmapRef);    CGImageRelease(bitmapImage);    return [UIImage imageWithCGImage:scaledImage];}@end

扫描二维码

1. 导入<AVFoundation/AVFoundation.h>

2. 扫描二维码实现

#import "ViewController.h"// 导入<AVFoundation/AVFoundation.h>框架#import <AVFoundation/AVFoundation.h>@interface ViewController ()<AVCaptureMetadataOutputObjectsDelegate>/** 捕捉会话 */@property (nonatomic, weak) AVCaptureSession *session;/** 预览图层 */@property (nonatomic, weak) AVCaptureVideoPreviewLayer *layer;@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    // 扫描二维码    [self scanCIQRCode];}/** *  扫描二维码 */- (void)scanCIQRCode{    // 1. 创建捕捉会话    AVCaptureSession *session = [[AVCaptureSession alloc] init];    self.session = session;    // 2. 添加输入设备(数据从摄像头输入)    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];    [session addInput:input];    // 3. 添加输出数据接口    AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc] init];    // 设置输出接口代理    [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];    [session addOutput:output];    // 3.1 设置输入元数据的类型(类型是二维码数据)    // 注意，这里必须设置在addOutput后面，否则会报错    [output setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode]];    // 4.添加扫描图层    AVCaptureVideoPreviewLayer *layer = [AVCaptureVideoPreviewLayer layerWithSession:session];    layer.frame = self.view.bounds;    [self.view.layer addSublayer:layer];    self.layer = layer;    // 5. 开始扫描    [session startRunning];}#pragma mark - <AVCaptureMetadataOutputObjectsDelegate>- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection{    if (metadataObjects.count) {// 扫描到了数据        AVMetadataMachineReadableCodeObject *object = [metadataObjects lastObject];        // 停止扫描        [self.session stopRunning];        // 将预览图层移除        [self.layer removeFromSuperlayer];    }else{        NSLog(@"没有扫描到数据");    }}@end

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