今天分享个小知识，项目需求生成二维码，然后把二维码图片保存到相册
很简单，使用系统方法
UIImageWriteToSavedPhotosAlbum(cgImage, self, @selector(imageSavedToPhotosAlbum:didFinishSavingWithError:contextInfo:), nil);
- (void)imageSavedToPhotosAlbum:(UIImage *)image didFinishSavingWithError:(NSError *)error contextInfo:(void *)contextInfo
{
NSString *message = @"";
if (!error) {
message = @"成功保存到相册";
[self.view makeToast:message duration:DisShowTime position:CSToastPositionBottom];
}else
{
message = [error description];
[self.view makeToast:@"保存失败" duration:DisShowTime position:CSToastPositionBottom];
}
NSLog(@"message is %@",message);
}
然后就发现保存成功， 相册中确没有找到
顺便把二维码生成也放上面
- (CIImage *)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 transformedImage;
}
下面直接结论了：
经过一番测试，发现方法[UIImage imageWithCIImage:codeImage];生产的UIImage并不算是实际意义上的图片UIImage.CGImage为nil，而相册保存方法UIImageWriteToSavedPhotosAlbum所保存的就是UIImage.CGImage
下面就简单了，先
CCImage ——> CGImage
CGImage ——> UIImage
// self.img 为 CIImage对象
CIFilter *filter = [CIFilter filterWithName:@"CISepiaTone"];
[filter setValue:self.img forKey:kCIInputImageKey];
[filter setValue:@0.5 forKey:kCIInputIntensityKey];
CIContext *context = [CIContext contextWithOptions:nil];
CGImageRef imageRef = [context createCGImage:filter.outputImage fromRect:filter.outputImage.extent];
UIImage *cgImage = [UIImage imageWithCGImage:imageRef];
此时cgImage.CGImage就有值了，在执行保存操作即可
