How to create a CGImageRef from a NSBitmapImageRep?

How can I create a CGImageRef from a NSBitmapImageRep? Or how can I define a complete new CGImageRef in the same way as the NSBitmapImageRep? The definition of a NSBitmapImageRep works fine. But I need an image as CGImageRef.

unsigned char *plane = (unsigned char *)[data bytes]; // data = 3 bytes for each RGB pixel

NSBitmapImageRep* imageRep = [[NSBitmapImageRep alloc]
                              initWithBitmapDataPlanes:     &plane
                              pixelsWide:                   width
                              pixelsHigh:                   height
                              bitsPerSample:                depth
                              samplesPerPixel:              channel
                              hasAlpha: NO
                              isPlanar: NO
                              colorSpaceName: NSCalibratedRGBColorSpace
                              //bitmapFormat: NSAlphaFirstBitmapFormat
                              bytesPerRow:                  channel * width
                              bitsPerPixel:                 channel * depth
                             ];

I have no idea how to create the CGImageRef from the NSBitmapImageRep or how to define a new CGImageRef:

CGImageRef imageRef = CGImageCreate(width, height, depth, channel*depth, channel*width, CGColorSpaceCreateDeviceRGB(), ... );

Please, can somebody give me a hint?

The easy way is by using the CGImage property (introduced in 10.5):

CGImageRef image = imageRep.CGImage;

Documentation:

https://developer.apple.com/library/mac/documentation/Cocoa/Reference/ApplicationKit/Classes/NSBitmapImageRep_Class/index.html#//apple_ref/occ/instm/NSBitmapImageRep/CGImage

Return Value

Returns an autoreleased CGImageRef opaque type based on the receiver’s current bitmap data.

Discussion

The returned CGImageRef has pixel dimensions that are identical to the receiver’s. This method might return a preexisting CGImageRef opaque type or create a new one. If the receiver is later modified, subsequent invocations of this method might return different CGImageRef opaque types.