Wrong touch point location in UIView after rotatation - ios

Question

I'm trying to make a custom button using a UIView and when touched on a specific part of the view perform an action, for example when touching the left part of the view log LEFT and when touching the Right part of the view log RIGHT.
I'm using touchesBegan and touchesEnded to detect touch.
Everything works fine when in portrait mode, however, once rotated to landscape mode it doesn't work, the view is displayed in the right place and the touch on the view is detected but it seems the touch point is not in the correct x,y coordinates so I can't detect the LEFT/RIGHT touches correctly.
Couldn't find any previous answers here that helped me.
Tried looking into CGAffineTransform, but still can't fix it.
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
self.backgroundColor = [[UIColor alloc] initWithPatternImage:[UIImage imageNamed:#"round_directions_button_default.png"]];
self.autoresizingMask = UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleTopMargin;
topLeft = CGPointMake(self.frame.origin.x, self.frame.origin.y);
topRight = CGPointMake(self.frame.origin.x + 105, self.frame.origin.y);
bottomLeft = CGPointMake(self.frame.origin.x, self.frame.origin.y + 105);
bottomRight = CGPointMake(self.frame.origin.x + 105, self.frame.origin.y + 105);
NSLog(#"topLeft: x = %f, y = %f", topLeft.x, topLeft.y);
NSLog(#"topRight: x = %f, y = %f", topRight.x, topRight.y);
NSLog(#"bottomLeft: x = %f, y = %f", bottomLeft.x, bottomLeft.y);
NSLog(#"bottomRight: x = %f, y = %f", bottomRight.x, bottomRight.y);
NSLog(#"self.center: x = %f, y = %f", self.center.x, self.center.y);
}
return self;
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"topLeft: x = %f, y = %f", topLeft.x, topLeft.y);
NSLog(#"topRight: x = %f, y = %f", topRight.x, topRight.y);
NSLog(#"bottomLeft: x = %f, y = %f", bottomLeft.x, bottomLeft.y);
NSLog(#"bottomRight: x = %f, y = %f", bottomRight.x, bottomRight.y);
NSLog(#"self.center: x = %f, y = %f", self.center.x, self.center.y);
UITouch *touch = [touches anyObject];
CGPoint touchPoint = [touch locationInView:nil];
NSLog(#"touchesBegan: touchPoint: x = %f, y = %f", touchPoint.x, touchPoint.y);
if ([self isPoint:touchPoint inTriangle:topLeft :self.center :topRight]) {
NSLog(#"touchesBegan: UP");
direction = 1;
self.backgroundColor = [[UIColor alloc] initWithPatternImage:[UIImage imageNamed:#"round_directions_button_pressed_up.png"]];
} else if ([self isPoint:touchPoint inTriangle:bottomLeft :self.center :bottomRight]) {
NSLog(#"touchesBegan: DOWN");
direction = 2;
self.backgroundColor = [[UIColor alloc] initWithPatternImage:[UIImage imageNamed:#"round_directions_button_pressed_down.png"]];
} else if ([self isPoint:touchPoint inTriangle:topLeft :self.center :bottomLeft]) {
NSLog(#"touchesBegan: LEFT");
direction = 3;
self.backgroundColor = [[UIColor alloc] initWithPatternImage:[UIImage imageNamed:#"round_directions_button_pressed_left.png"]];
} else if ([self isPoint:touchPoint inTriangle:topRight :self.center :bottomRight]) {
NSLog(#"touchesBegan: RIGHT");
direction = 4;
self.backgroundColor = [[UIColor alloc] initWithPatternImage:[UIImage imageNamed:#"round_directions_button_pressed_right.png"]];
} else {
NSLog(#"touchesBegan: NOTHING");
}
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
self.backgroundColor = [[UIColor alloc] initWithPatternImage:[UIImage imageNamed:#"round_directions_button_default.png"]];
}
- (BOOL) isPoint:(CGPoint)point inTriangle:(CGPoint)v1 :(CGPoint)v2 :(CGPoint)v3 {
BOOL b1, b2, b3;
b1 = ((point.x - v2.x) * (v1.y - v2.y) - (v1.x - v2.x) * (point.y - v2.y)) < 0.0f;
b2 = ((point.x - v3.x) * (v2.y - v3.y) - (v2.x - v3.x) * (point.y - v3.y)) < 0.0f;
b3 = ((point.x - v1.x) * (v3.y - v1.y) - (v3.x - v1.x) * (point.y - v1.y)) < 0.0f;
return ((b1 == b2) && (b2 == b3));
}
in view controller viewDidLoad:
CustomButton *customButton = [[CustomButton alloc] initWithFrame:CGRectMake(1, self.view.bounds.size.height - 106, 105, 105)];
[self.view addSubview:customButton];
Any help will be appreciated.
Thanks

Answer 1

If the size of the button doesn't change with rotation you can set points just once inside initWithFrame and use bounds instead of frame.
topLeft = CGPointMake(0, 0);
topRight = CGPointMake(self.bounds.size.width, 0);
bottomLeft = CGPointMake(0, self.bounds.size.height);
bottomRight = CGPointMake(self.bounds.size.width, self.bounds.size.height);
Then in touchesBegan use [touch locationInView:self]; to get the touch location in the button own coordinate system.
If the size changes, a solution can be to recalculate points on every touch so place the above code inside touchesBegan.
EDIT:
If you want to use local button coordinate you have to calculate the center because self.center contains center point of the view in the superview’s coordinate system.