iOS 根据图片URL生成自定义大小的二维码

调用方法

UIImage *QRImg = [self generateQRCode:urlStr width:qrCodeImgWidth height:qrCodeImgWidth];

生成二维码方法

#pragma mark - 生成条形码以及二维码
- (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];
}