[black bear theory]

i have a document-based coredata program that draws a series of lines on top of an image. it may sound weird but there's a reason for it.

i've created a bunch of entities to handle the lines and they are managed by a NSArrayControllers (set up in IB) and hooked into the "File Owner's" managedObjectContext. there isn't a problem with the data; i can open and close documents and all the data remains through the different operations.

however, i can't figure out how to manage the image. there is only one image per document and (possibly) many lines. adding the image each time you open a document is not ideal.

i have tried creating a NSObjectController in MyDocument.nib file and i can access the image via [_imageController content] after the image is set, however, the image isn't retained when a document is closed and reopened, though the data remains.

the thing i like about coredata is that all the data for my app is handled automatically, but i need some pointers on how to manage the one image for each document so that it is present each time i open the document.

[Chuckit]

Maybe I'm misunderstanding, but I'd just create an Image entity with a binary data attribute to store the image's data.

[black bear theory]

i was thinking that might be the way, but i'm still having some trouble. i've set up the NSObjectController of entity "ImageMO".

i have this code in MyDocument.m:

Code:
-(void)awakeFromNib { 
	NSLog(@"awakeFromNib");
	NSImage *savedImage = [_imageController content];
	if (savedImage) {
		NSLog(@"found some content");
		[self setImage:savedImage];
	} else {
		NSLog(@"no content available");
	}
}

- (void)setImage:(NSImage *)value {
    if (image != value) {
        [image release];
        image = [value copy];
		[_view setImage:image];
		[_imageController setContent:image];

    }
	
	NSLog(@"now back in mydocument");
	
	NSLog(@"image %@", image);
	
	NSLog(@"image content %@", [_imageController content]);
}

and when i run the program, here is the output:

Code:
[Session started at 2007-06-20 11:54:58 -0800.]

// 1 

2007-06-20 11:54:58.876 Scanline[21485] awakeFromNib
2007-06-20 11:54:58.876 Scanline[21485] no content available

// 2

2007-06-20 11:55:03.318 Scanline[21485] now back in mydocument
2007-06-20 11:55:03.318 Scanline[21485] image NSImage 0x3ec980 Size={1024, 768} Reps=(
    NSBitmapImageRep 0x3d8120 Size={1024, 768} ColorSpace=NSCalibratedRGBColorSpace BPS=8 BPP=24 Pixels=1024x768 Alpha=NO Planar=NO Format=0
)
2007-06-20 11:55:03.319 Scanline[21485] image content NSImage 0x3ec980 Size={1024, 768} Reps=(
    NSBitmapImageRep 0x3d8120 Size={1024, 768} ColorSpace=NSCalibratedRGBColorSpace BPS=8 BPP=24 Pixels=1024x768 Alpha=NO Planar=NO Format=0
)

// 3

2007-06-20 11:55:07.277 Scanline[21485] awakeFromNib
2007-06-20 11:55:07.277 Scanline[21485] found some content
2007-06-20 11:55:07.277 Scanline[21485] now back in mydocument
2007-06-20 11:55:07.277 Scanline[21485] image NSImage 0x3ec980 Size={1024, 768} Reps=(
    NSBitmapImageRep 0x3d8120 Size={1024, 768} ColorSpace=NSCalibratedRGBColorSpace BPS=8 BPP=24 Pixels=1024x768 Alpha=NO Planar=NO Format=0
)
2007-06-20 11:55:07.277 Scanline[21485] image content NSImage 0x3ec980 Size={1024, 768} Reps=(
    NSBitmapImageRep 0x3d8120 Size={1024, 768} ColorSpace=NSCalibratedRGBColorSpace BPS=8 BPP=24 Pixels=1024x768 Alpha=NO Planar=NO Format=0
)

// 4

2007-06-20 11:55:18.169 Scanline[21485] awakeFromNib
2007-06-20 11:55:18.169 Scanline[21485] no content available

i added the comments.

the above output is generated when i 1) create a new document 2) add the image 3) close and save the document and then 4) reopen the document.

i'm not sure why awakeFromNib is being called a second time when i am in the process of saving.

are there any obvious steps i've messed up? i know that _imageController is hooked up properly because i can see it.

i guess i can see one problem. even though imageController is of entity "ImageMO" i just call it's setContent:. i get errors if i try something like:

Code:
[_imageController setContent:image] // ok
[_imageController setImage:image] // warning, doesn't function either

[black bear theory]

Originally Posted by Chuckit 

Maybe I'm misunderstanding, but I'd just create an Image entity with a binary data attribute to store the image's data.

after struggling with this and then re-reading your post i figured out what you meant. :) i remembered doing something like this for a color well i had.

i added ImageMO:

@implementation ImageMO

- (void)awakeFromFetch {
NSData *imageData = [self valueForKey:@"imageData"];
if (imageData != nil) {
NSLog(@"ImageMO : attempting to load imageData : %@", imageData);
NSImage *image = [NSUnarchiver unarchiveObjectWithData:imageData];
[self setPrimitiveValue:image forKey:@"image"];
} else {
NSLog(@"ImageMO : no data found :(");
}
}

-(void)willSave {
NSImage *tmpImage = [self primitiveValueForKey:@"image"];
if (tmpImage != nil) {
NSLog(@"ImageMO : trying to save : %@", tmpImage);
[self setPrimitiveValue:[NSArchiver archivedDataWithRootObject:tmpImage] forKey:@"imageData"];
} else {
NSLog(@"ImageMO : no data to save : %@", tmpImage);
[self setPrimitiveValue:nil forKey:@"imageData"];
}

[super willSave];
}


- (NSImage *)image
{
NSImage *tmpValue;

[self willAccessValueForKey: @"image"];
tmpValue = [self primitiveValueForKey: @"image"];
[self didAccessValueForKey: @"image"];

return tmpValue;
}

- (void)setImage:(NSImage *)value
{
[self willChangeValueForKey: @"image"];
[self setPrimitiveValue: value forKey: @"image"];
[self didChangeValueForKey: @"image"];
}

- (BOOL)validateImage: (id *)valueRef error:(NSError **)outError
{
// Insert custom validation logic here.
return YES;
}

- (NSData *)imageData
{
NSData * tmpValue;

[self willAccessValueForKey: @"imageData"];
tmpValue = [self primitiveValueForKey: @"imageData"];
[self didAccessValueForKey: @"imageData"];

return tmpValue;
}

- (void)setImageData:(NSData *)value
{
[self willChangeValueForKey: @"imageData"];
[self setPrimitiveValue: value forKey: @"imageData"];
[self didChangeValueForKey: @"imageData"];
}

- (BOOL)validateImageData: (id *)valueRef error:(NSError **)outError
{
// Insert custom validation logic here.
return YES;
}

@end

setup/code is the same as above post (aside from some NSLog's taken out). _imageController is an entity of type ImageMO and bound to "File Owner's" managedObjectContext.

here is the output:

[Session started at 2007-06-20 21:28:52 -0800.]
2007-06-20 21:28:52.933 Scanline[25050] doc : no content available
2007-06-20 21:29:04.269 Scanline[25050] doc : found some content - NSImage 0x3d3e70 Size={1024, 768} Reps=(
NSBitmapImageRep 0x3e9a60 Size={1024, 768} ColorSpace=NSCalibratedRGBColorSpace BPS=8 BPP=24 Pixels=1024x768 Alpha=NO Planar=NO Format=0
)
2007-06-20 21:29:06.212 Scanline[25050] ImageMO : trying to save : NSImage 0x3d3e70 Size={1024, 768} Reps=(
NSBitmapImageRep 0x3e9a60 Size={1024, 768} ColorSpace=NSCalibratedRGBColorSpace BPS=8 BPP=24 Pixels=1024x768 Alpha=NO Planar=NO Format=0
)
2007-06-20 21:29:10.535 Scanline[25050] doc : no content available
2007-06-20 21:30:07.521 Scanline[25050] doc : no content available

awakeFromFetch doesn't seem to be called?

[Chuckit]

You need to call [super awakeFromFetch] before you do your initialization, I believe.

[black bear theory]

no. that doesn't work. anyway, i should get the "no data found" message.

it's probably something simple. and stupid. it always is.

[edit: it was. ]