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  • 生成二维码

    #import "ViewController.h"
    #import <CoreImage/CoreImage.h>
    
    @interface ViewController ()
    @property (weak, nonatomic) IBOutlet UIImageView *imageView;
    
    @end
    
    @implementation ViewController
    
    - (void)viewDidLoad {
        [super viewDidLoad];
    }
    
    - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
    {
        // 1.创建过滤器
        CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
        
        // 2.恢复默认
        [filter setDefaults];
        
        // 3.给过滤器添加数据(正则表达式/账号和密码)
        NSString *dataString = @"http://www.520it.com";
        NSData *data = [dataString dataUsingEncoding:NSUTF8StringEncoding];
        [filter setValue:data forKeyPath:@"inputMessage"];
        
        // 4.获取输出的二维码
        CIImage *outputImage = [filter outputImage];
        
        // 5.显示二维码
        self.imageView.image = [self createNonInterpolatedUIImageFormCIImage:outputImage withSize:200];
    }
    
    /**
     *  根据CIImage生成指定大小的UIImage
     *
     *  @param image CIImage
     *  @param size  图片宽度
     */
    - (UIImage *)createNonInterpolatedUIImageFormCIImage:(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到图片
        CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
        CGContextRelease(bitmapRef);
        CGImageRelease(bitmapImage);
        return [UIImage imageWithCGImage:scaledImage];
    }
    
    @end
    

      

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  • 原文地址:https://www.cnblogs.com/yedayi/p/5140583.html
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