iOS 生成二维码，生成条形码图片

#pragma mark - 生成条形码以及二维码

// 参考文档
// https://developer.apple.com/library/mac/documentation/GraphicsImaging/Reference/CoreImageFilterReference/index.html

- (UIImage *)generateQRCode:(NSString *)code width:(CGFloat)width height:(CGFloat)height {
    
    // 生成二维码图片
    CIImage *qrcodeImage;
    NSData *data = [code dataUsingEncoding:NSISOLatin1StringEncoding allowLossyConversion:false];
    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    
    [filter setValue:data forKey:@"inputMessage"];
    [filter setValue:@"H" forKey:@"inputCorrectionLevel"];
    qrcodeImage = [filter outputImage];
    
    // 消除模糊
    CGFloat scaleX = width / qrcodeImage.extent.size.width; // extent 返回图片的frame
    CGFloat scaleY = height / qrcodeImage.extent.size.height;
    CIImage *transformedImage = [qrcodeImage imageByApplyingTransform:CGAffineTransformScale(CGAffineTransformIdentity, scaleX, scaleY)];
    
    return [UIImage imageWithCIImage:transformedImage];
}

- (UIImage *)generateBarCode:(NSString *)code width:(CGFloat)width height:(CGFloat)height {
    // 生成条码图片
    CIImage *barcodeImage;
    NSData *data = [_code dataUsingEncoding:NSISOLatin1StringEncoding allowLossyConversion:false];
    CIFilter *filter = [CIFilter filterWithName:@"CICode128BarcodeGenerator"];
    
    [filter setValue:data forKey:@"inputMessage"];
    barcodeImage = [filter outputImage];
    
    // 消除模糊
    CGFloat scaleX = width / barcodeImage.extent.size.width; // extent 返回图片的frame
    CGFloat scaleY = height / barcodeImage.extent.size.height;
    CIImage *transformedImage = [barcodeImage imageByApplyingTransform:CGAffineTransformScale(CGAffineTransformIdentity, scaleX, scaleY)];
    
    return [UIImage imageWithCIImage:transformedImage];
}