How do you get the image data from NSAttributedString - cocoa

Question

I have an NSTextView. I paste an image into it and see it. When I get the NSTextAttachment for the NSAttributedString of the text view, it's file wrapper is nil. How do I get the image data that was pasted into the text view?
I'm using a category on NSAttributedString to get the text attachments. I would prefer not to write to disk if it's possible.
- (NSArray *)allAttachments
{
NSError *error = NULL;
NSMutableArray *theAttachments = [NSMutableArray array];
NSRange theStringRange = NSMakeRange(0, [self length]);
if (theStringRange.length > 0)
{
NSUInteger N = 0;
do
{
NSRange theEffectiveRange;
NSDictionary *theAttributes = [self attributesAtIndex:N longestEffectiveRange:&theEffectiveRange inRange:theStringRange];
NSTextAttachment *theAttachment = [theAttributes objectForKey:NSAttachmentAttributeName];
if (theAttachment != NULL){
NSLog(#"filewrapper: %#", theAttachment.fileWrapper);
[theAttachments addObject:theAttachment];
}
N = theEffectiveRange.location + theEffectiveRange.length;
}
while (N < theStringRange.length);
}
return(theAttachments);
}

Answer 1

Enumerate the attachments. [NSTextStorage enumerateAttribute:...]
Get the attachment's filewrapper.
Write to a URL.
[textStorage enumerateAttribute:NSAttachmentAttributeName
inRange:NSMakeRange(0, textStorage.length)
options:0
usingBlock:^(id value, NSRange range, BOOL *stop)
{
NSTextAttachment* attachment = (NSTextAttachment*)value;
NSFileWrapper* attachmentWrapper = attachment.fileWrapper;
[attachmentWrapper writeToURL:outputURL options:NSFileWrapperWritingAtomic originalContentsURL:nil error:nil];
(*stop) = YES; // stop so we only write the first attachment
}];
This sample code will only write the first attachment to outputURL.

Answer 2

You can get the contained NSImage from the attachment cell.
Minimalistic example:
// assuming we have a NSTextStorage* textStorage object ready to go,
// and that we know it contains an attachment at some_index
// (in real code we would probably enumerate attachments).
NSRange range;
NSDictionary* textStorageAttrDict = [textStorage attributesAtIndex:some_index
longestEffectiveRange:&range
inRange:NSMakeRange(0,textStorage.length)];
NSTextAttachment* textAttachment = [textStorageAttributesDictionary objectForKey:#"NSAttachment"];
NSTextAttachmentCell* textAttachmentCell = textAttachment.attachmentCell;
NSImage* attachmentImage = textAttachmentCell.image;
EDITING:
OS X only (AppKit version)

Answer 3

#EmeraldWeapon's answer is good for Objective-C, but falls down in Swift, as in Swift the attachmentCell is not an NSTextAttachmentCell, but rather an NSTextAttachmentCellProtocol? (which does not provide .image) - so you need to cast it to a concrete instance before accessing the .image:
func firstImage(textStorage: NSTextStorage) -> NSImage? {
for idx in 0 ..< textStorage.string.count {
if
let attr = textStorage.attribute(NSAttributedString.Key.attachment, at: idx, effectiveRange: nil),
let attachment = attr as? NSTextAttachment,
let cell = attachment.attachmentCell as? NSTextAttachmentCell,
let image = cell.image {
return image
}
}
return nil
}