二维码生成

#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.创建滤镜对象

    CIFilter *fiter = [CIFilter filterWithName:@"CIQRCodeGenerator"];

    

    // 2.设置相关属性

    [fiter setDefaults];

    

    // 3.设置输入数据

    NSString *inputData = @"http://www.baidu.com";

    NSData *data = [inputData dataUsingEncoding:NSUTF8StringEncoding];

    [fiter setValue:data forKeyPath:@"inputMessage"];

    

    // 4.获取输出结果

    CIImage *outputImage = [fiter 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