Empirical determination of TouchUpInside area

TestView.m

//
//  TestView.m
//  ButtonHitTest
//
//  Created by Hamish Allan on 03/01/2012.
//

#import "TestView.h"

@implementation TestView
{
    UIView *myArea;
    UIButton *myButton;
}

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    
    if (self)
    {
        myArea = [[UIView alloc] init];
        myArea.backgroundColor = [UIColor redColor];
        
        myButton = [[UIButton alloc] init];
        myButton.backgroundColor = [UIColor blueColor];
        myButton.showsTouchWhenHighlighted = YES;
        
        [myButton addTarget:self action:@selector(touchUpInside:forEvent:) forControlEvents:UIControlEventTouchUpInside];
        [myButton addTarget:self action:@selector(touchUpOutside:forEvent:) forControlEvents:UIControlEventTouchUpOutside];
        [myButton addTarget:self action:@selector(touchDragInside:forEvent:) forControlEvents:UIControlEventTouchDragInside];
        [myButton addTarget:self action:@selector(touchDragOutside:forEvent:) forControlEvents:UIControlEventTouchDragOutside];

        [self addSubview:myArea];
        [self addSubview:myButton];
    }
    
    return self;
}

- (void)layoutSubviews
{
    [super layoutSubviews];
    
    myButton.bounds = CGRectMake(0.0, 0.0, 44.0, 44.0);
    myButton.center = self.center;
    
    CGRect touchUpArea = CGRectInset(myButton.bounds, -70.0, -70.0); // determined from NSLog output
    myArea.frame = [myButton convertRect:touchUpArea toView:self];
}

- (void)touchUpInside:(id)sender forEvent:(UIEvent *)event
{
    CGPoint location = [[[event touchesForView:myButton] anyObject] locationInView:myButton];
    NSLog(@"touchUpInside: %@", NSStringFromCGPoint(location));
}

- (void)touchUpOutside:(id)sender forEvent:(UIEvent *)event
{
    CGPoint location = [[[event touchesForView:myButton] anyObject] locationInView:myButton];
    NSLog(@"touchUpOutside: %@", NSStringFromCGPoint(location));
}

- (void)touchDragInside:(id)sender forEvent:(UIEvent *)event
{
    CGPoint location = [[[event touchesForView:myButton] anyObject] locationInView:myButton];
    NSLog(@"touchDragInside: %@", NSStringFromCGPoint(location));
}

- (void)touchDragOutside:(id)sender forEvent:(UIEvent *)event
{
    CGPoint location = [[[event touchesForView:myButton] anyObject] locationInView:myButton];
    NSLog(@"touchDragOutside: %@", NSStringFromCGPoint(location));
}

@end