iOS -- 生成有logo的二維碼

- (void)createLogoImage {
    NSArray *filter = [CIFilter filterNamesInCategory:kCICategoryBuiltIn];
    NSLog(@"%@", filter);
    // 二維碼過濾器
    CIFilter *filterImage = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    // 將二位碼過濾器設置為默認屬性
    [filterImage setDefaults];
    // 將文字轉化為二進制
    NSData *dataImage = [@"mafeng" dataUsingEncoding:NSUTF8StringEncoding];
    // 打印輸入的屬性
    NSLog(@"%@", filterImage.inputKeys);
    // KVC 賦值
    [filterImage setValue:dataImage forKey:@"inputMessage"];
    // 取出輸出圖片
    CIImage *outputImage = [filterImage outputImage];
    outputImage = [outputImage imageByApplyingTransform:CGAffineTransformMakeScale(20, 20)];
    // 轉化圖片
    UIImage *image = [UIImage imageWithCIImage:outputImage];
    
    // 為二維碼加自定義圖片
    
    // 開啟繪圖, 獲取圖片 上下文<圖片大小>
    UIGraphicsBeginImageContext(image.size);
    // 將二維碼圖片畫上去
    [image drawInRect:CGRectMake(0, 0, image.size.width, image.size.height)];
    // 將小圖片畫上去
    UIImage *smallImage = [UIImage imageNamed:@"123.jpg"];
    [smallImage drawInRect:CGRectMake((image.size.width - 100) / 2, (image.size.width - 100) / 2, 100, 100)];
    // 獲取最終的圖片
    UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
    // 關閉上下文
    UIGraphicsEndImageContext();
    // 顯示
    self.imageview.image = finalImage;
    
    
}