PackagedDocument/AttachmentView.m

/*
     File: AttachmentView.m
 Abstract: Custom view holding the image to attach to our document.
  Version: 1.1
 
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 */
 
#import "AttachmentView.h"
#import "MyWindowController.h"
 
@interface AttachmentView ()
@property BOOL highlightForDragAcceptence;
@end
 
@implementation AttachmentView
 
- (void)commonInit
{
    // register for all the image types we can display -- include NSFilenamesPboardType for Finder drags.
    NSMutableArray *dragTypes = [[NSImage imagePasteboardTypes] mutableCopy];
    [dragTypes addObject:NSFilenamesPboardType];
    [self registerForDraggedTypes:dragTypes];
    
    [self setKeyboardFocusRingNeedsDisplayInRect:[self bounds]];
    
    self.highlightForDragAcceptence = NO;
}
 
- (id)initWithCoder:(NSCoder *)coder
{
    // init method called for Interface Builder objects
    self = [super initWithCoder:coder];
    if (self)
    {
        [self commonInit];
    }
    return self;
}
 
- (id)initWithFrame:(NSRect)frame
{
    self = [super initWithFrame:frame];
    if (self)
    {
        [self commonInit];
    }
    
    return self;
}
 
- (void)drawRect:(NSRect)rect
{
    [super drawRect:rect];
 
    // draw the focus frame if necessary
    if (self.highlightForDragAcceptence)
    {
        [NSGraphicsContext saveGraphicsState];
        NSSetFocusRingStyle(NSFocusRingOnly);
        [[NSBezierPath bezierPathWithRect: NSInsetRect(self.bounds,3,3)] fill];
        [NSGraphicsContext restoreGraphicsState];
    }
}
 
- (void)dealloc
{
    [self unregisterDraggedTypes];
    // since we are using ARC no need to call super
}
 
- (NSDragOperation)draggingEntered:(id <NSDraggingInfo>)sender
{
    if ((NSDragOperationCopy & [sender draggingSourceOperationMask]) == NSDragOperationCopy)
    {
        self.highlightForDragAcceptence = YES;
        [self setNeedsDisplay:YES];
        
        // the sender is offering the type of operation we want,
        // return that we want the NSDragOperationCopy (cursor has a + image)
        //
        return NSDragOperationCopy;
    }
    else
    {
        // we aren't interested in this drag
        return NSDragOperationNone;
    }
}
 
- (void)draggingExited:(id <NSDraggingInfo>)sender
{
    // user has left our drag area, erase our focus frame
    self.highlightForDragAcceptence = NO;
    [self setNeedsDisplay:YES];
}
 
- (NSDragOperation)draggingUpdated:(id <NSDraggingInfo>)sender
{
    if ((NSDragOperationCopy & [sender draggingSourceOperationMask]) == NSDragOperationCopy)
    {
        // the sender is offering the type of operation we want,
        // return that we want the NSDragOperationCopy (cursor has a + image)
        //
        return NSDragOperationCopy;
    }
    else
    {
        // we aren't interested in this drag
        return NSDragOperationNone;
    }
}
 
- (void)draggingEnded:(id <NSDraggingInfo>)sender
{
    //..
}
 
- (BOOL)prepareForDragOperation:(id <NSDraggingInfo>)sender
{
    return YES;
}
 
- (BOOL)performDragOperation:(id <NSDraggingInfo>)sender
{
    NSPasteboard *paste = [sender draggingPasteboard];
    
    // gets the dragging-specific pasteboard from the sender
    NSArray *types = [NSArray arrayWithObjects:NSTIFFPboardType, NSFilenamesPboardType, nil];
    
    // a list of types that we can accept
    NSString *desiredType = [paste availableTypeFromArray:types];
    NSData *carriedData = [paste dataForType:desiredType];
    
    if (carriedData == nil)
    {
        // the drag operation failed
        return NO;
    }
    else
    {
        // the pasteboard was able to give us some meaningful data
        if ([desiredType isEqualToString:NSTIFFPboardType])
        {
            // We have TIFF bitmap data in the NSData object.
            // Keep a reference to the image for drawing
            self.image = [[NSImage alloc] initWithData:carriedData];
            
        }
        else if ([desiredType isEqualToString:NSFilenamesPboardType])
        {
            // we have a list of file names in an NSData object
            NSArray *fileArray = [paste propertyListForType:@"NSFilenamesPboardType"];
 
            NSString *path = [fileArray objectAtIndex:0];
            
            // assume that we can ignore all but the first path in the list
            NSImage *newImage = [[NSImage alloc] initWithContentsOfFile:path];
            if (newImage == nil)
            {
                // failed to open the file
                return NO;
            }
            else
            {
                // Keep a reference to the image for drawing
                self.image = newImage;
                
                // tell our window controller that a new image was dragged in by the user
                MyWindowController *windowController = (MyWindowController *)[[self window] windowController];
                [windowController updateImage:newImage];
            }
        }
        else
        {
            return NO;
        }
    }
    
    // erase the drag acceptance highlight, and draws the new image
    self.highlightForDragAcceptence = NO;
    [self setNeedsDisplay:YES];
 
    return YES;
}
 
@end