YYFPSLabel

#import <UIKit/UIKit.h>

/**
 Show Screen FPS...
 
 The maximum fps in OSX/iOS Simulator is 60.00.
 The maximum fps on iPhone is 59.97.
 The maxmium fps on iPad is 60.0.
 */
@interface YYFPSLabel : UILabel

@end


//
//  YYWeakProxy.h
//  YYKit <https://github.com/ibireme/YYKit>
//
//  Created by ibireme on 14/10/18.
//  Copyright (c) 2015 ibireme.
//
//  This source code is licensed under the MIT-style license found in the
//  LICENSE file in the root directory of this source tree.
//
/**
 A proxy used to hold a weak object.
 It can be used to avoid retain cycles, such as the target in NSTimer or CADisplayLink.
 
 sample code:
 
 @implementation MyView {
 NSTimer *_timer;
 }
 
 - (void)initTimer {
 YYWeakProxy *proxy = [YYWeakProxy proxyWithTarget:self];
 _timer = [NSTimer timerWithTimeInterval:0.1 target:proxy selector:@selector(tick:) userInfo:nil repeats:YES];
 }
 
 - (void)tick:(NSTimer *)timer {...}
 @end
 */
@interface YYWeakProxy : NSProxy

/**
 The proxy target.
 */
@property (nonatomic, weak, readonly) id target;

/**
 Creates a new weak proxy for target.
 
 @param target Target object.
 
 @return A new proxy object.
 */
- (instancetype)initWithTarget:(id)target;

/**
 Creates a new weak proxy for target.
 
 @param target Target object.
 
 @return A new proxy object.
 */
+ (instancetype)proxyWithTarget:(id)target;

@end

///==========================================
#import "YYFPSLabel.h"
#define kSize CGSizeMake(55, 20)

@implementation YYFPSLabel {
    CADisplayLink *_link;
    NSUInteger _count;
    NSTimeInterval _lastTime;
    UIFont *_font;
    UIFont *_subFont;
    
    NSTimeInterval _llll;
}

- (instancetype)initWithFrame:(CGRect)frame {
    if (frame.size.width == 0 && frame.size.height == 0) {
        frame.size = kSize;
    }
    self = [super initWithFrame:frame];
    
    self.layer.cornerRadius = 5;
    self.clipsToBounds = YES;
    self.textAlignment = NSTextAlignmentCenter;
    self.userInteractionEnabled = NO;
    self.backgroundColor = [UIColor colorWithWhite:0.000 alpha:0.700];
    
    _font = [UIFont fontWithName:@"Menlo" size:14];
    if (_font) {
        _subFont = [UIFont fontWithName:@"Menlo" size:4];
    } else {
        _font = [UIFont fontWithName:@"Courier" size:14];
        _subFont = [UIFont fontWithName:@"Courier" size:4];
    }
    
    _link = [CADisplayLink displayLinkWithTarget:[YYWeakProxy proxyWithTarget:self] selector:@selector(tick:)];
    [_link addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];
    return self;
}

- (void)dealloc {
    [_link invalidate];
}

- (CGSize)sizeThatFits:(CGSize)size {
    return kSize;
}

- (void)tick:(CADisplayLink *)link {
    if (_lastTime == 0) {
        _lastTime = link.timestamp;
        return;
    }
    
    _count++;
    NSTimeInterval delta = link.timestamp - _lastTime;
    if (delta < 1) return;
    _lastTime = link.timestamp;
    float fps = _count / delta;
    _count = 0;
    
    CGFloat progress = fps / 60.0;
    UIColor *color = [UIColor colorWithHue:0.27 * (progress - 0.2) saturation:1 brightness:0.9 alpha:1];
    
    NSMutableAttributedString *text = [[NSMutableAttributedString alloc] initWithString:[NSString stringWithFormat:@"%d FPS",(int)round(fps)]];
    self.textColor = color;
    self.attributedText = text;
}

@end


#import <Foundation/Foundation.h>

@implementation YYWeakProxy

- (instancetype)initWithTarget:(id)target {
    _target = target;
    return self;
}

+ (instancetype)proxyWithTarget:(id)target {
    return [[YYWeakProxy alloc] initWithTarget:target];
}

- (id)forwardingTargetForSelector:(SEL)selector {
    return _target;
}

- (void)forwardInvocation:(NSInvocation *)invocation {
    void *null = NULL;
    [invocation setReturnValue:&null];
}

- (NSMethodSignature *)methodSignatureForSelector:(SEL)selector {
    return [NSObject instanceMethodSignatureForSelector:@selector(init)];
}

- (BOOL)respondsToSelector:(SEL)aSelector {
    return [_target respondsToSelector:aSelector];
}

- (BOOL)isEqual:(id)object {
    return [_target isEqual:object];
}

- (NSUInteger)hash {
    return [_target hash];
}

- (Class)superclass {
    return [_target superclass];
}

- (Class)class {
    return [_target class];
}

- (BOOL)isKindOfClass:(Class)aClass {
    return [_target isKindOfClass:aClass];
}

- (BOOL)isMemberOfClass:(Class)aClass {
    return [_target isMemberOfClass:aClass];
}

- (BOOL)conformsToProtocol:(Protocol *)aProtocol {
    return [_target conformsToProtocol:aProtocol];
}

- (BOOL)isProxy {
    return YES;
}

- (NSString *)description {
    return [_target description];
}

- (NSString *)debugDescription {
    return [_target debugDescription];
}

@end

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController

@end
///==========================================
#import "ViewController.h"
#import "YYFPSLabel.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    YYFPSLabel *label = [[YYFPSLabel alloc] init];
    label.frame = CGRectMake((CGRectGetWidth([UIScreen mainScreen].bounds)- 100)/2.0f, 0, 100, 30);
    [self.navigationController.navigationBar addSubview:label];
}

@end