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社区首页 >专栏 >Core Animation实战三(图层几何学)

Core Animation实战三(图层几何学)

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星宇大前端
发布2019-01-15 15:12:41
4180
发布2019-01-15 15:12:41
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文章被收录于专栏:大宇笔记

锚点

了解游戏的人一般都知道锚点,在UIView中我们很少用到。anchorPoint位于图层的中点,所以图层的将会以这个点为中心放置。anchorPoint属性并没有被UIView接口暴露出来,这也是视图的position属性被叫做“center”的原因。但是图层的anchorPoint可以被移动,比如你可以把它置于图层frame的左上角,于是图层的内容将会向右下角的position方向移动(图3.3),而不是居中了。

Demo:

主要是看下指针的位置

Xib指针位置如图(锚点在中心位置):

最后效果如下:

Demo代码:

代码语言:javascript
复制
//
//  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;
    
    //设置锚点
    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

坐标系和Hit Testing

CALayer并不关心任何响应链事件,所以不能直接处理触摸事件或者手势。但是它有一系列的方法帮你处理事件:-containsPoint:-hitTest:

-containsPoint:接受一个在本图层坐标系下的CGPoint,如果这个点在图层frame范围内就返回YES

-hitTest:方法同样接受一个CGPoint类型参数,而不是BOOL类型,它返回图层本身,或者包含这个坐标点的叶子节点图层。这意味着不再需要像使用-containsPoint:那样,人工地在每个子图层变换或者测试点击的坐标。如果这个点在最外面图层的范围之外,则返回nil。

代码语言:javascript
复制
//
//  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 判断较麻烦,需要把坐标转换图层成每个坐标系下的坐标
-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    
    CGPoint point  =  [[touches anyObject] locationInView:self.view];
    //将点击的点从以 self.view.layer 为父类的坐标系转到self.wildView.layer为父类的坐标系
    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];
//    //返回点击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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原始发表:2017年10月30日,如有侵权请联系 cloudcommunity@tencent.com 删除

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目录
  • 锚点
  • 坐标系和Hit Testing
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