NSImageRep Class Reference

Discussion

This method should be overridden by subclasses. Note that this method does not need to do a comprehensive check of the image data; it should return NO only if it knows it cannot initialize itself from the data.

Discussion

This method invokes the imageUnfilteredPasteboardTypes class method and checks the list of types returned by that method against the data types in pasteboard. If it finds a match, it returns YES. When creating a subclass of NSImageRep that accepts image data from a non-default pasteboard type, override the imageUnfilteredPasteboardTypes method to assure this method returns the correct response.

Discussion

The list includes both those types returned by the imageUnfilteredFileTypes class method plus those that can be converted to a supported type by a user-installed filter service. The returned file types can include encoded HFS file types as well as filename extensions.

Don’t override this method when subclassing NSImageRep—it always returns a valid list for any subclass of NSImageRep that correctly overrides the imageUnfilteredFileTypes method.

Discussion

The list includes both those types returned by the imageUnfilteredPasteboardTypes class method plus those that can be converted to a supported type by a user-installed filter service. Don’t override this method when subclassing NSImageRep—it always returns a valid list for any subclass of NSImageRep that correctly overrides the imageUnfilteredPasteboardTypes method.

Discussion

If sent to the NSImageRep class object, this method returns an array of objects (all newly allocated instances of a subclass of NSImageRep, chosen through the use of imageRepClassForFileType:) that have been initialized with the contents of the file. If sent to a subclass of NSImageRep that recognizes the file type, this method returns an array of objects (all instances of that subclass) that have been initialized with the contents of the file.

This method returns nil in any of the following cases:

• The message is sent to the NSImageRep class object and there are no subclasses in the NSImageRep class registry that handle the data in the file.

• The message is sent to a subclass of NSImageRep and that subclass cannot handle the data in the file.

• The NSImageRep subclass is unable to initialize itself with the contents of filename.

The NSImageRep subclass is initialized by creating an NSData object based on the contents of the file and passing it to the imageRepsWithData: method of the subclass. By default, the files handled include those with the extensions “tiff”, “gif”, “jpg”, “pict”, “pdf”, and “eps”.

Discussion

If sent to the NSImageRep class object, this method returns an array of objects (all newly allocated instances of a subclass of NSImageRep) that have been initialized with the contents of the specified URL. If sent to a subclass of NSImageRep that recognizes the data at the specified URL, it returns an array of objects (all instances of that subclass) that have been initialized with the contents of that URL.

This method returns nil in any of the following cases:

• The message is sent to the NSImageRep class object and there are no subclasses in the NSImageRep class registry that handle data in the specified URL.

• The message is sent to a subclass of NSImageRep and that subclass cannot handle data in the specified URL.

• The NSImageRep subclass is unable to initialize itself with the contents of the specified URL.

The NSImageRep subclass is initialized by creating an NSData object based on the contents of the specified URL and passing it to the imageRepsWithData: method.

Discussion

If sent to the NSImageRep class object, this method returns an array of objects (all newly-allocated instances of a subclass of NSImageRep) that have been initialized with the data in the specified pasteboard. If sent to a subclass of NSImageRep that recognizes the pasteboard data, it returns an array of objects (all instances of that subclass) initialized with the pasteboard data.

This method returns nil in any of the following cases:

• The message is sent to the NSImageRep class object and there are no subclasses in the NSImageRep class registry that handle the pasteboard data.

• The message is sent to a subclass of NSImageRep and that subclass cannot handle the pasteboard data.

• The NSImageRep subclass is unable to initialize itself with the contents the pasteboard.

The NSImageRep subclass is initialized by creating an NSData object based on the data in pasteboard and passing it to the imageRepsWithData: method.

Discussion

If sent to the NSImageRep class object, this method returns a newly allocated instance of a subclass of NSImageRep (chosen through the use of imageRepClassForFileType:) initialized with the contents of the specified file. If sent to a subclass of NSImageRep that recognizes the type of data in the file, it returns an instance of that subclass initialized with the contents of the file.

This method returns nil in any of the following cases:

• The message is sent to the NSImageRep class object and there are no subclasses in the NSImageRep class registry that handle the type of data in the specified file.

• The message is sent to a subclass of NSImageRep and that subclass cannot handle the type of data in the specified file.

• The NSImageRep subclass is unable to initialize itself with the contents of the specified file.

The NSImageRep subclass is initialized by creating an NSData object based on the contents of the file and passing it to the imageRepWithData: method. By default, the files handled include those with the extensions “tiff”, “gif”, “jpg”, “pict”, “pdf”, and “eps”.

Discussion

If sent to the NSImageRep class object, this method returns a newly allocated instance of a subclass of NSImageRep initialized with the contents of the specified URL. If sent to a subclass of NSImageRep that recognizes the data contained in the URL, it returns an instance of that subclass initialized with the data in the URL.

This method returns nil in any of the following cases:

• The message is sent to the NSImageRep class object and there are no subclasses in the NSImageRep class registry that handle the data contained in the specified URL.

• The message is sent to a subclass of NSImageRep and that subclass cannot handle the data contained in the specified URL.

• The NSImageRep subclass is unable to initialize itself with the contents of the specified URL.

The NSImageRep subclass is initialized by creating an NSData object based on the contents of the file, then passing it to the imageRepWithData: method.

Discussion

If sent to the NSImageRep class object, this method returns a newly allocated instance of a subclass of NSImageRep initialized with the data in the specified pasteboard. If sent to a subclass of NSImageRep that recognizes the data on the pasteboard, it returns an instance of that subclass initialized with that data.

This method returns nil in any of the following cases:

• The message is sent to the NSImageRep class object and there are no subclasses in the NSImageRep class registry that handle data of the type contained in the specified pasteboard.

• The message is sent to a subclass of NSImageRep and that subclass cannot handle data of the type contained in the specified pasteboard.

• The NSImageRep subclass is unable to initialize itself with the contents of the pasteboard.

The NSImageRep subclass is initialized by creating an NSData object based on the data the specified pasteboard and passing it to the imageRepWithData: method.

Discussion

The returned list includes UTIs all file types supported by this image representation object plus those that can be opened by this image representation after being converted by a user-installed filter service. You can use the returned UTI strings with any method that supports UTIs.

Discussion

The returned file types can include encoded HFS file types as well as filename extensions. When creating a subclass of NSImageRep, override this method to return a list of strings representing the supported file types. For example, the NSBitmapImageRep class implements code similar to the following for this method:

+ (NSArray *)imageUnfilteredFileTypes {

    static NSArray *types = nil;

    if (!types) types = [[NSArray alloc]

        initWithObjects:@"tiff", @"gif", @"jpg",  @"bmp", nil];

    return types;

}

If your subclass supports the types supported by its superclass, you must explicitly get the array of types from the superclass and put them in the array returned by this method.

Discussion

When creating a subclass of NSImageRep, override this method to return a list representing the supported pasteboard types. For example, the NSBitmapImageRep class implements code similar to the following for this method:

+ (NSArray *)imageUnfilteredPasteboardTypes {

    static NSArray *types = nil;

    if (!types) types = [[NSArray alloc] initWithObjects:NSTIFFPboardType,  nil];

    return types;

}

If your subclass supports the types supported by its superclass, you must explicitly get the list of types from the superclass and add them to the array returned by this method.

Discussion

The returned list includes UTI strings only for those file types that are supported directly by the receiver. It does not include types that are supported through user-installed filter services. You can use the returned UTI strings with any method that supports UTIs.

Discussion

This method posts an NSImageRepRegistryDidChangeNotification, along with the receiving object, to the default notification center.

A good place to add image representation classes to the registry is in the load class method.

Discussion

This method posts the NSImageRepRegistryDidChangeNotification, along with the receiving object, to the default notification center.