最近看了看，怎么在应用中生成二维码，感觉挺好玩的。以下是核心代码。

黑白二维码代码

/// 黑白二维码
- (void)test
{
    // 二维码本质是字符串
    //    NSArray *array = [CIFilter filterNamesInCategory:kCICategoryBuiltIn];
    //    NSLog(@"%@",array);w
    // 1.获取二维码的过滤器
    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    // 2.设置默认值
    [filter setDefaults];
    // 3.获取过滤器的值
    NSLog(@"%@",filter.inputKeys);
    // 4.设置二维码内容
    NSString *string = @"哈哈哈哈哈";
    // inputMessage必须使用NSData类型,否则就崩溃
    [filter setValue:[string dataUsingEncoding:NSUTF8StringEncoding] forKey:@"inputMessage"];
    // 5.取出图片
    CIImage *ciimage = filter.outputImage;
    NSLog(@"%@",ciimage);
    // 修改图片大小
    ciimage = [ciimage imageByApplyingTransform:CGAffineTransformMakeScale(6, 6)];
    UIImage *image = [UIImage imageWithCIImage:ciimage];
    self.imageView.image = image;
}

运行后的效果

Snip20160523_4.png

彩色二维码加居中小图片

- (void)viewDidLoad {
    [super viewDidLoad];
    // 二维码本质是字符串
    NSArray *array = [CIFilter filterNamesInCategory:kCICategoryBuiltIn];
    NSLog(@"%@",array);
    // 1.获取二维码的过滤器
    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    // 2.设置默认值
    [filter setDefaults];
    // 3.获取过滤器的值
    NSLog(@"%@",filter.inputKeys);
    // 4.设置二维码内容
    NSString *string = @"哈哈哈哈哈";
    // inputMessage必须使用NSData类型,否则就崩溃
    [filter setValue:[string dataUsingEncoding:NSUTF8StringEncoding] forKey:@"inputMessage"];
    // 5.取出图片
    CIImage *ciimage = filter.outputImage;
//    NSLog(@"%@",ciimage);
    
    // 6.生成颜色过滤器
    /*
     inputImage,   需要设置颜色的图片
     inputColor0,  前景色
     inputColor1   背景色
     */ 
    // 6.1颜色过滤器
    CIFilter *colorFilter = [CIFilter filterWithName:@"CIFalseColor"];
    // 6.2设置默认值
    [colorFilter setDefaults];
    // 6.3打印可以使用的值
    NSLog(@"%@",colorFilter.inputKeys);
    // 6.4设置添加颜色的图片
    [colorFilter setValue:ciimage forKey:@"inputImage"];
    // 6.5设置前景色
//    [colorFilter setValue:[CIColor colorWithRed:1 green:0 blue:0 alpha:1] forKey:@"inputColor0"];
//    // 6.5设置背景色
//    [colorFilter setValue:[CIColor colorWithRed:0 green:1 blue:0 alpha:1] forKey:@"inputColor1"];
    // 6.6获取设置完颜色的图片
//    ciimage = colorFilter.outputImage;
    // 7.修改图片大小
    ciimage = [ciimage imageByApplyingTransform:CGAffineTransformMakeScale(6, 6)];
    UIImage *image = [UIImage imageWithCIImage:ciimage];
    // 8.添加中间图片
    // 8.1开启图形上下文
    UIGraphicsBeginImageContext(image.size);
    // 8.2画二维码图片
    [image drawInRect:CGRectMake(0, 0, image.size.width, image.size.height)];
    // 8.3画中间的图片
    UIImage *meImage = [UIImage imageNamed:@"程序员"];
    CGFloat meImageW = 40;
    CGFloat meImageH = 40;
    CGFloat meImageX = (image.size.width - meImageW) * 0.5;
    CGFloat meImageY = (image.size.height - meImageH) * 0.5;
    [meImage drawInRect:CGRectMake(meImageX, meImageY, meImageW, meImageH)];
    // 8.4取出图片
    UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
    // 8.5关闭图形上下文
    UIGraphicsEndImageContext();
    
    
    // 9.显示图片
    self.imageView.image = finalImage;
}

运行效果

Snip20160523_6.png