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[操作系统]iOS原生CIFilter创建二维码


iOS原生CIFilter创建二维码

2016-05-31 未来C

iOS原生CIFilter创建二维码


 

 

关于二维码生成,网上也是有很多,很早以前的第三方库大多数都是通过C++写,也是有的如zxing,也是挺好用,这里介绍的是通过CIFilter创建二维码。

 

 

 

创建二维码非常简单,只要传入简单的字符串就好了
 - (CIImage *)createQRForString:(NSString *)qrString {  NSData *stringData = [qrString dataUsingEncoding:NSUTF8StringEncoding];  // 创建filter  CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];  // 设置内容和纠错级别  [qrFilter setValue:stringData forKey:@"inputMessage"];  [qrFilter setValue:@"M" forKey:@"inputCorrectionLevel"];  // 返回CIImage  return qrFilter.outputImage;}

 

 

 

为生成的二维码是一个CIImage,我们直接转换成UIImage的话大小不好控制,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.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);   //原图  UIImage *outputImage = [UIImage imageWithCGImage:scaledImage];   UIGraphicsBeginImageContextWithOptions(outputImage.size, NO, [[UIScreen mainScreen] scale]);  [outputImage drawInRect:CGRectMake(0,0 , size, size)];  //水印图  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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