2016-1-8 Quartz框架的学习，多个气球上升的小动画

//
//  BallonView.m
//  气球上升的动画
//
//  Created by Mac on 16/1/8.
//  Copyright © 2016年 Mac. All rights reserved.
//
 
#import "BallonView.h"
@interface BallonView()
 
@property (nonatomic, assign) NSString *postions;
@property (nonatomic, strong) CADisplayLink *link;
@property (nonatomic, strong) NSMutableArray *locations;
@property (nonatomic, strong) NSMutableArray *ballons;
 
@end
@implementation BallonView
//懒加载 存储位置
- (NSMutableArray *)locations
{
    if (!_locations) {
        _locations = [NSMutableArray array];
    }
    return _locations;
}
- (NSMutableArray *)ballons
{
    if (!_ballons) {
        _ballons = [NSMutableArray array];
        NSInteger count = ;
        UIImage *ballonImage =[UIImage imageNamed:@"sandyBalloon"];
        for (int i = ; i < count; i ++) {
            CGFloat left = ;
            CGPoint location = CGPointMake(left*(i+), self.frame.size.height - );
//            [ballonImage drawAtPoint:location];
            [self.locations addObject:[NSValue valueWithCGPoint:location]];
            [_ballons addObject:ballonImage];
        }
    }
   return _ballons;
}
 
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
    NSInteger ballonsOfCount = self.ballons.count;
    for (int i = ; i < ballonsOfCount; i ++) {
//        获取气球的位置
        CGPoint postion = [self.locations[i] CGPointValue];
        postion.y -= arc4random_uniform() * 0.7;
        if (postion.y == ) {
            postion.y = rect.size.height;
        }
 
        [self.locations replaceObjectAtIndex:i withObject:[NSValue valueWithCGPoint:postion]];
        [self.ballons[i] drawAtPoint:postion];
    }
    NSLog(@"%s",__func__);
 
}
 
//    ------------------------------------------------------------------------------------------------------------------
    // Drawing code
 
- (instancetype)init
{
    if (self = [super init]) {
        [self addAnimition];
    }
    return self;
}
- (void) addAnimition
{
//    [NSTimer scheduledTimerWithTimeInterval:0.01 target:self selector:@selector(setNeedsDisplay) userInfo:nil repeats:YES];
    CADisplayLink *link = [CADisplayLink displayLinkWithTarget:self selector:@selector(setNeedsDisplay)];
    [link addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];
    self.link = link;
}
- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event
{
    [self.link invalidate];
}
 
@end