get CGRect location in superview objective-c - objective-c

Question

I want to print out the x coordinate of a CGRect. The x,y coordinates of the rect is set to where the user touches, like this:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [[event allTouches]anyObject];
startPoint = [touch locationInView:self];
}
- (void)drawRect:(CGRect)rect
{
ctx = UIGraphicsGetCurrentContext();
jrect = CGRectMake(startPoint.x, startPoint.y, 100, 100);
CGContextAddRect(ctx, jrect);
CGContextFillPath(ctx);
}
I could just print out the startPoint but if I would print out the CGRect's coordinate I tried to do this:
int jrectX = lroundf(CGRectGetMinX(jrect));
xlabel.text = [NSString stringWithFormat:#"x: %i", jrectX];
But the number it returns doesn't make any sense at all, sometimes they are bigger to the left than to the right. Is there anything wrong with the code?

Answer 1

A CGRect is a struct with four CGFloat properties: x, y, width, height
To print the x value from a CGRect:
[NSString stringWithFormat:#"%f", rect.x]
To print the entire rect, there's a convenience function:
NSStringFromCGRect(rect)
You're having problems above, because you're storing the x value into an int, and then using a float rounding function on it. So it should be:
CGFloat jrectX = CGRectGetMinX(jrect);
. . . unless you're doing rotation transformation, you can just use:
CGFloat jrectX = jrect.origin.x;

Answer 2

DR.h
#import <UIKit/UIKit.h>
#interface DR : UIView
{
CGContextRef ctx;
CGRect jrect;
CGPoint startPoint;
UILabel *xlabel;
}
#end
DR.m file.
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
xlabel=[[UILabel alloc] initWithFrame:CGRectMake(0, 0, 100, 100)];
[self addSubview:xlabel];
// Initialization code
}
return self;
}
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{
ctx = UIGraphicsGetCurrentContext();
jrect = CGRectMake(startPoint.x, startPoint.y, 100, 100);
CGContextAddRect(ctx, jrect);
CGContextFillPath(ctx);
// Drawing code
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
UITouch *touch = [[event allTouches]anyObject];
startPoint = [touch locationInView:self];
int jrectX = lroundf(CGRectGetMinX(jrect));
NSLog(#"jrectX --------------");
xlabel.text = [NSString stringWithFormat:#"x: %i", jrectX];
[self setNeedsDisplay];
}
#end
In other viewController use it...
- (void)viewDidLoad
{
DR *drr=[[DR alloc] initWithFrame:CGRectMake(0, 0, 320, 460)];
[drr setBackgroundColor:[UIColor greenColor]];
[self.view addSubview:drr];
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}