docs:programming:cocoa_and_objective-c:nsview [hartungdesign.net wiki]

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====== NSView ======
Below we are using the NSImageRep object to draw into the view, instead of using the NSImage class.  The NSImageRep class allows us to select a representation, which is calculated elsewhere with "repOffset."

actualSize is used to set the image size to the actual pixels.  I don't fully understand why the system sometimes decides to use a size other than pixel size for a typical graphics file.
<code>
- (void)drawRect:(NSRect)rect
{

	if(image != nil){	
		NSImageRep *myRep = (NSImageRep *)[[image representations] objectAtIndex:repOffset];
		NSSize actualSize = NSMakeSize([myRep pixelsWide],[myRep pixelsHigh]);

		[myRep setSize:actualSize];
		rect.size = actualSize;
		
		// fix scrolling origin...
		// the superview of this class is the contentView of the scrollView, which
		// is of the NSClipView class
		NSRect contentFrame = [(NSView *)[self superview] frame];
		rect.origin = contentFrame.origin;

		[self setFrameSize:actualSize];

		[myRep drawInRect:rect];
		
	}
	
}
</code>