Detect clicked segment in NSSegmentedCell subclass

gistfile1.txt

// --------------------  CRSegmentedCell.h ------------------------------

#import <Cocoa/Cocoa.h>


@interface CRSegmentedCell : NSSegmentedCell {
	NSInteger highlightedSegment;
}
@property(assign) NSInteger highlightedSegment;
@end



// --------------------  CRSegmentedCell.m ------------------------------

#import "CRSegmentedCell.h"


@implementation CRSegmentedCell
@synthesize highlightedSegment;

- (id)initWithCoder:(NSCoder *)decoder;
{
	if (![super initWithCoder:decoder])
		return nil;
	[self setHighlightedSegment:-1];
	return self;
}


- (BOOL)trackMouse:(NSEvent *)event inRect:(NSRect)cellFrame ofView:(NSView *)controlView untilMouseUp:(BOOL)untilMouseUp;
{ 
	[self setHighlightedSegment:-1];
	NSPoint loc = [event locationInWindow];
	NSRect frame = cellFrame;
	NSUInteger i = 0, count = [self segmentCount];
	loc = [controlView convertPoint:loc fromView:nil];
	while(i < count && frame.origin.x < cellFrame.size.width) { 
		frame.size.width = [self widthForSegment:i];
		if(NSMouseInRect(loc, frame, NO))
		{
			[self setHighlightedSegment:i];
			break;
		}
		frame.origin.x+=frame.size.width;
		i++;
	}
	[controlView setNeedsDisplay:YES];
 	return [super trackMouse:event inRect:cellFrame ofView:controlView untilMouseUp:untilMouseUp];
}

- (void)stopTracking:(NSPoint)lastPoint at:(NSPoint)stopPoint inView:(NSView *)controlView mouseIsUp:(BOOL)flag;
{
	[self setHighlightedSegment:-1];
	[super stopTracking:lastPoint at:stopPoint inView:controlView mouseIsUp:flag];
}

@end

thanks!