Core Animation實戰三（圖層幾何學）

ZY_FlyWay發表於2017-10-30
原文網址 : https://blog.csdn.net/zy_flyway/article/details/78391652

錨點

   瞭解遊戲的人一般都知道錨點，在UIView中我們很少用到。anchorPoint位於圖層的中點，所以圖層的將會以這個點為中心放置。anchorPoint屬性並沒有被UIView介面暴露出來，這也是檢視的position屬性被叫做“center”的原因。但是圖層的anchorPoint可以被移動，比如你可以把它置於圖層frame的左上角，於是圖層的內容將會向右下角的position方向移動（圖3.3），而不是居中了。


Demo:

主要是看下指標的位置

Xib指標位置如圖（錨點在中心位置）：




最後效果如下:




Demo程式碼：

//
//  ClockViewController.m
//  LayerStudyDemo
//
//  Created by apple on 2017/9/25.
//  Copyright © 2017年 ZY. All rights reserved.
//

#import "ClockViewController.h"

@interface ClockViewController ()
@property (weak, nonatomic) IBOutlet UILabel *hourLabel;
@property (weak, nonatomic) IBOutlet UILabel *minuteLabel;
@property (weak, nonatomic) IBOutlet UILabel *secondLabel;
@property (nonatomic, weak) NSTimer *timer;
@end

@implementation ClockViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    self.timer = [NSTimer scheduledTimerWithTimeInterval:1.0f target:self selector:@selector(showTime) userInfo:nil repeats:YES];
}

-(void)showTime{
    NSCalendar  * calendar = [[NSCalendar alloc]initWithCalendarIdentifier:NSCalendarIdentifierChinese];
    NSUInteger units = NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond;
    NSDateComponents *components = [calendar components:units fromDate:[NSDate date]];
    CGFloat hoursAngle = (components.hour / 12.0) * M_PI * 2.0;
    //calculate hour hand angle //calculate minute hand angle
    CGFloat minsAngle = (components.minute / 60.0) * M_PI * 2.0;
    //calculate second hand angle
    CGFloat secsAngle = (components.second / 60.0) * M_PI * 2.0;
    
    //設定錨點
    self.hourLabel.layer.anchorPoint =self.minuteLabel.layer.anchorPoint =self.secondLabel.layer.anchorPoint = CGPointMake(0.5f, 0.9f);
    
    //rotate hands
    self.hourLabel.transform = CGAffineTransformMakeRotation(hoursAngle);
    self.minuteLabel.transform = CGAffineTransformMakeRotation(minsAngle);
    self.secondLabel.transform = CGAffineTransformMakeRotation(secsAngle);
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

@end

座標系和Hit Testing

CALayer並不關心任何響應鏈事件，所以不能直接處理觸控事件或者手勢。但是它有一系列的方法幫你處理事件：-containsPoint:和-hitTest:。


-containsPoint:接受一個在本圖層座標系下的CGPoint，如果這個點在圖層frame範圍內就返回YES。


-hitTest:方法同樣接受一個CGPoint型別引數，而不是BOOL型別，它返回圖層本身，或者包含這個座標點的葉子節點圖層。這意味著不再需要像使用-containsPoint:那樣，人工地在每個子圖層變換或者測試點選的座標。如果這個點在最外面圖層的範圍之外，則返回nil。


//
//  HitTestingViewController.m
//  LayerStudyDemo
//
//  Created by apple on 2017/9/25.
//  Copyright © 2017年 ZY. All rights reserved.
//

#import "HitTestingViewController.h"

@interface HitTestingViewController ()
@property (weak, nonatomic) IBOutlet UIView *wildView;
@property (nonatomic, strong) CALayer *innerLayer;
@end

@implementation HitTestingViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self creatInnerLayer];
}

-(void)creatInnerLayer{
    self.innerLayer = [CALayer layer];
    self.innerLayer.frame = CGRectMake((self.wildView.frame.size.width-100)/2, (self.wildView.frame.size.height-100)/2, 100.0f, 100.0f);
    self.innerLayer.backgroundColor = [UIColor blueColor].CGColor;
    //add it to our view
    [self.wildView.layer addSublayer:self.innerLayer];
}

// containsPoint 判斷較麻煩，需要把座標轉換圖層成每個座標系下的座標
-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    
    CGPoint point  =  [[touches anyObject] locationInView:self.view];
    //將點選的點從以 self.view.layer 為父類的座標系轉到self.wildView.layer為父類的座標系
    point = [self.wildView.layer convertPoint:point fromLayer:self.view.layer];
    if ([self.wildView.layer containsPoint:point]) {
        //convert point to blueLayer’s coordinates
        point = [self.innerLayer convertPoint:point fromLayer:self.wildView.layer];
        if ([self.innerLayer containsPoint:point]) {
            [[[UIAlertView alloc] initWithTitle:@"Inside innerLayer Layer"
                                        message:nil
                                       delegate:nil
                              cancelButtonTitle:@"OK"
                              otherButtonTitles:nil] show];
        } else {
            [[[UIAlertView alloc] initWithTitle:@"Inside wildView Layer"
                                        message:nil
                                       delegate:nil
                              cancelButtonTitle:@"OK"
                              otherButtonTitles:nil] show];
        }
    }
    
}
 

//-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
//
//    CGPoint point  =  [[touches anyObject] locationInView:self.view];
//    //返回點選layer
//    CALayer * hitLayer = [self.wildView.layer hitTest:point];
//    if (hitLayer==self.innerLayer) {
//
//            [[[UIAlertView alloc] initWithTitle:@"Inside innerLayer Layer"
//                                        message:nil
//                                       delegate:nil
//                              cancelButtonTitle:@"OK"
//                              otherButtonTitles:nil] show];
//    } else if(hitLayer==self.wildView.layer){
//            [[[UIAlertView alloc] initWithTitle:@"Inside wildView Layer"
//                                        message:nil
//                                       delegate:nil
//                              cancelButtonTitle:@"OK"
//                              otherButtonTitles:nil] show];
//    }else{
//        [[[UIAlertView alloc] initWithTitle:@"Inside  View"
//                                    message:nil
//                                   delegate:nil
//                          cancelButtonTitle:@"OK"
//                          otherButtonTitles:nil] show];
//    }
//}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}



@end


DEMO地址

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