NSImageRep

Inherits From: NSObject

Conforms To: NSCoding, NSCopying NSObject (NSObject)

Declared In: AppKit/NSImageRep.h

Class Description

NSImageRep is an abstract superclass; each of its subclasses knows how to draw an image from a particular kind of source data. While an NSImageRep subclass can be used directly, it's typically used through an NSImage object. An NSImage manages a group of representations, choosing the best one for the current output device.

There are four subclasses defined in the Application Kit:

Subclass Source Data

NSBitmapImageRep Tag Image File Format (TIFF) and other bitmap data

NSEPSImageRep Encapsulated PostScript code (EPS)

NSCustomImageRep A delegated method that can draw the image

NSCachedImageRep A rendered image, usually in an off-screen window

You can define other NSImageRep subclasses for objects that render images from other types of source information. New subclasses must be added to the NSImageRep class registry by invoking the registerImageRepClass: class method. The NSImageRep subclass informs the registry of the data types it can support through its imageUnfilteredFileTypes, imageUnfilteredPasteboardTypes, and canInitWithData: class methods. Once an NSImageRep subclass is registered, an instance of that subclass is created anytime NSImage encounters the type of data handled by that subclass.

Creating an NSImageRep

• + (id)imageRepWithContentsOfFile:(NSString *)filename In subclasses that respond to imageFileTypes and imageRepWithData:, returns an object that has been initialized with the data in filename. NSImageRep's implementation returns an instance of the appropriate registered subclass.
• + (NSArray *)imageRepsWithContentsOfFile:(NSString *)filename In subclasses that respond to imageFileTypes and imageRepWithData: (or imageRepWithData:), returns an array of objects that have been initialized with the data in filename. NSImageRep's implementation returns an array of objects (each an instance of the appropriate registered subclass) that have been initialized with the data in filename.
• + (id)imageRepWithPasteboard:(NSPasteboard *)pasteboard In subclasses that respond to imagePasteboardTypes and imageRepWithData:, returns an object that has been initialized with the data in pasteboard. NSImageRep's implementation returns an instance of the appropriate registered subclass.
• + (NSArray *)imageRepsWithPasteboard:(NSPasteboard *)pasteboard In subclasses that respond to imagePasteboardTypes and imageRepsWithData: (or imageRepWithData:), returns an array of objects that have been initialized with the data in pasteboard. NSImageRep's implementation returns an array of objects (each an instance of the appropriate registered subclass) that have been initialized with the data in pasteboard.

• + (BOOL)canInitWithData:(NSData *)data Overridden in subclasses to return YES if the receiver can initialize itself from data.
• + (BOOL)canInitWithPasteboard:(NSPasteboard *)pasteboard Overridden in subclasses to returnYES if the receiver can initialize itself from pasteboard.
• + (NSArray *)imageFileTypes Returns an array of strings representing all file types.
• + (NSArray *)imagePasteboardTypes Returns an array of strings representing all pasteboard types.
• + (NSArray *)imageUnfilteredFileTypes Returns an array of strings representing directly supported file types.
• + (NSArray *)imageUnfilteredPasteboardTypes Returns an array of strings representing directly supported pasteboards.

• - (void)setSize:(NSSize)aSize Sets the size of the image.
• - (NSSize)size Returns the size of the image.

• - (int)bitsPerSample Returns the number of bits per pixel in each component.
• - (NSString *)colorSpaceName Returns the name of the image's color space.
• - (BOOL)hasAlpha Returns whether there is a coverage component.
• - (BOOL)isOpaque Returns whether the representation is opaque.
• - (int)pixelsHigh Returns the height specified in the image data.
• - (int)pixelsWide Returns the width specified in the image data.
• - (void)setAlpha:(BOOL)flag Informs the receiver whether there is a coverage component.
• - (void)setBitsPerSample:(int)anInt Informs the receiver there are anInt bits/pixel in a component.
• - (void)setColorSpaceName:(NSString *)aString Informs the receiver of the image's color space.
• - (void)setOpaque:(BOOL)flag Informs the receiver of the image's opacity.
• - (void)setPixelsHigh:(int)anInt Informs the receiver that its data is for an image anInt pixels high.
• - (void)setPixelsWide:(int)anInt Informs the receiver that its data is for an image anInt pixels wide.

• - (BOOL)draw Implemented by subclasses to draw the image.
• - (BOOL)drawAtPoint:(NSPoint)aPoint Modifies current coordinates so the image is drawn at aPoint.
• - (BOOL)drawInRect:(NSRect)aRect Modifies current coordinates so the image is drawn in aRect.

• + (Class)imageRepClassForData:(NSData *)data Returns the NSImageRep subclass that handles data of type data.
• + (Class)imageRepClassForFileType:(NSString *)type Returns the NSImageRep subclass that handles data of file type type.
• + (Class)imageRepClassForPasteboardType:(NSString *)type Returns the NSImageRep subclass that handles data of pasteboard type type.
• + (void)registerImageRepClass:(Class)imageRepClass Adds imageRepClass to the registry of available NSImageRep classes. This method posts the NSImageRepRegistryChangedNotification notification with the receiving object to the default notification center.
• + (NSArray *)registeredImageRepClasses Returns the names of the registered NSImageRep classes.
• + (void)unregisterImageRepClass:(Class)imageRepClass Removes imageRepClass from the registry of available NSImageRep classes. This method posts the NSImageRepRegistryChangedNotification notification with the receiving object to the default notification center.