iOS原生CIFilter建立二維碼，ioscifilter

iOS原生CIFilter建立二維碼，ioscifilter
iOS原生CIFilter建立二維碼2016-05-31 未來C

iOS原生CIFilter建立二維碼

 

 

關於二維碼產生，網上也是有很多，很早以前的第三方庫大多數都是通過C++寫，也是有的如zxing，也是挺好用，這裡介紹的是通過CIFilter建立二維碼。

 

 

 

建立二維碼非常簡單，只要傳入簡單的字串就好了

 - (CIImage *)createQRForString:(NSString *)qrString {    NSData *stringData = [qrString dataUsingEncoding:NSUTF8StringEncoding];    // 建立filter    CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];    // 設定內容和錯誤修正層級    [qrFilter setValue:stringData forKey:@"inputMessage"];    [qrFilter setValue:@"M" forKey:@"inputCorrectionLevel"];    // 返回CIImage    return qrFilter.outputImage;}

 

 

 

為產生的二維碼是一個CIImage，我們直接轉換成UIImage的話大小不好控制，所以使用下面方法返回需要大小的UIImage：

 

- (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size {    CGRect extent = CGRectIntegral(image.extent);    CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));   // 1.建立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.儲存bitmap到圖片    CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);    CGContextRelease(bitmapRef);     CGImageRelease(bitmapImage);     //原圖    UIImage *outputImage = [UIImage imageWithCGImage:scaledImage];     UIGraphicsBeginImageContextWithOptions(outputImage.size, NO, [[UIScreen mainScreen] scale]);    [outputImage drawInRect:CGRectMake(0,0 , size, size)];    //浮水印圖    UIImage *waterimage = [UIImage imageNamed:@"icon"];    [waterimage drawInRect:CGRectMake((size-waterImagesize)/2.0, (size-waterImagesize)/2.0, waterImagesize, waterImagesize)];    UIImage *newPic = UIGraphicsGetImageFromCurrentImageContext();    UIGraphicsEndImageContext();    return newPic; }

 

 

 

 

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