save UIImage to NSUserDefaults

Why don't you save a path to the image file instead of bloating up the prefs?

NSUserDefaults is for simple things like strings, numbers, etc. To save a UIImage, save it as a file in your app's Documents directory.

UIImage has the property "CGImage" of type CGImageRef which can get you the actual image data. CGImageRef is really a pointer to a CGImage object.

A CGImage object has the method "representationUsingType:properties:" which returns an NSData object containing the image data in a PNG, JPEG, BMP, etc.

Finally, NSData has "writeToFile:" methods that will save the data to a file.

Sorry, my mistake, I was looking at a different class. Here's another way. I haven't tested this, but it should get you on the right track.

UIImage *theImage;
// ...
CFDataRef dataRef = CGDataProviderCopyData(CGImageGetDataProvider(theImage.CGImage));
const UInt8 *bytes = CFDataGetBytePtr(dataRef);
CFIndex length = CFDataGetLength(dataRef);
NSData *dataObj = [NSData dataWithBytesNoCopy:(void*)bytes length:(NSUInteger)length freeWhenDone:NO];
[dataObj writeToFile:@"MySavedImage.bmp" atomically:NO];

Check out the CGImage reference:
http://developer.apple.com/iphone/library/documentation/GraphicsImaging/Referenc e/CGImage/Reference/reference.html

And this page under "How do I obtain raw pixel data...":
http://developer.apple.com/iphone/library/codinghowtos/GraphicsAndAnimation/inde x.html#2D-OBTAINRAW_PIXEL_DATA_FROM_MYIMAGES

If you realy want to save an UIImage to NSUserDefaults you can use the NSKeyedArchiver class.

NSData *imageData;
// create NSData-object from image
imageData = [NSKeyedArchiver archivedDataWithRootObject:yourUIImage];
// save NSData-object to UserDefaults
...

This is very helpful to a project I am working on. I am very unfamiliar with saving and restoring settings. Would you mind showing the code that saves the NSData-object to UserDefaults.

Thanks

Hi, that's quite simple:

NSData *imageData;
 
// create NSData-object from image
imageData = [NSKeyedArchiver archivedDataWithRootObject:yourUIImage];
// save NSData-object to UserDefaults
[[NSUserDefaults standardUserDefaults] setObject:imageData forKey:@"image"];

To load that image back on application-start use:

NSData *imageData;
imageData = [[NSUserDefaults standardUserDefaults] objectForKey:@"image"];
if (imageData != nil) {
 yourUIImage = [NSKeyedUnarchiver unarchiveObjectWithData: imageData];
}

Thank you so much. I was actually pretty close but my app keep terminating when my picture attempts to save. I must not be translating my image properly.

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
 if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
 
 NSData *imageData;
 UIImage *theImage;
 imageData = [[NSUserDefaults standardUserDefaults] objectForKey:@"image"];
 if (imageData != nil) {
 theImage = [NSKeyedUnarchiver unarchiveObjectWithData: imageData];
 }
 }
 return self;
}
- (IBAction)openPicker {
 if ([UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypePhotoLibrary])
 {
 UIImagePickerController *picker;
 picker = [[UIImagePickerController alloc]init];
 picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
 picker.allowsImageEditing = YES;
 picker.delegate = self;
 [self presentModalViewController:picker animated:YES];
 }
}
- (void)imagePickerController:(UIImagePickerController *)picker
 didFinishPickingImage:(UIImage *)image
 editingInfo:(NSDictionary *)editingInfo {
 
 [self useImage:image];
 [[picker parentViewController] dismissModalViewControllerAnimated:YES];
 
}
-(void)useImage:(UIImage *)theImage {
 pickerImage.image = theImage;
 
 NSData *imageData;
 
 imageData = [NSKeyedArchiver archivedDataWithRootObject:theImage];
 [[NSUserDefaults standardUserDefaults] setObject:imageData forKey:@"image"];
}

Are you getting an exception? What is the error you are getting?

After pressing "Choose" in the UIImagePickerController I go into perpetual "Saving photo" mode and never get out of it.

I ran across this page while trying to figure out how to save a UIImage to a png or jpg file, so I thought I'd post the two-line solution here that I finally found.

//Save to PNG
 NSData *dataObj = UIImagePNGRepresentation(self);
 [dataObj writeToFile:path atomically:NO];

//Save to JPG
 NSData *dataObj = UIImageJPEGRepresentation(self, 90);
 [dataObj writeToFile:path atomically:NO];

Message was edited by: wurp

Message was edited by: wurp

If you are running on the simulator that is expected behavior. The camera is not supported on the simulator.

Hi
I want to save my images data to database on the server side,
what should i do for that
after taking the picture
i will have one image thats what i know
how to deal with that and how to convert that to some string kind of data
so that i should pass that as parameter and save to the database on the server
and later after getting the data how to render that as image again
do you have any logic for that.
please help me , i dont have any idea how to encode and decode the image to some string or some thing. please mail me at narender.mudgal@gmail.com
thanks a lot