//獲取兩個圓之間的距離CGFloat distance = [self distanceWithSmallCircle:self.smallCircle bigCircle:self];if(distance<=MAX_DIST){//只有距離不超過最大距離才計算小圓半徑 //計算小圓的半徑 //小圓半徑最小的時候是MIN_RADIUS,這個時候兩個圓達到最大距離MAX_DIST //小圓半徑最大的時候是原始半徑，這個時候兩圓距離是0 //處于前面兩者之間的時候，小圓的半徑是：MIN_RADIUS + (原始半徑 - MIN_RADIUS)/MAX_DIST * （MAX_DIST - 當前的距離） CGFloat smallR = self.bounds.size.width * 0.5; smallR = MIN_RADIUS + (MAX_DIST-distance) * (smallR-MIN_RADIUS)/MAX_DIST; //重新設置小圓的尺寸 self.smallCircle.bounds = CGRectMake(0, 0, smallR*2, smallR*2); //重新設置小圓的半徑 self.smallCircle.layer.cornerRadius = smallR;}else{//超過了最大距離 self.smallCircle.hidden = YES;}

//// BageValueView.m// 03_UIView78_粒子效果2//// Created by 杞文明 on 17/7/22.// Copyright © 2017年 杞文明. All rights reserved.//#import "BageValueView.h"#define MAX_DIST 80#define MIN_RADIUS 5@interface BageValueView()@property (nonatomic, weak) UIView *smallCircle;@property (nonatomic, weak) CAShapeLayer *shap;@end@implementation BageValueView-(void)awakeFromNib{ [self setUp];}-(instancetype)initWithFrame:(CGRect)frame{ if ( self = [super initWithFrame:frame] ) {  [self setUp]; } return self;}//形狀圖層-(CAShapeLayer*)shap{ if(_shap == nil){  //形狀圖層，它可以根據一個路徑生成一個形狀  CAShapeLayer *shap = [CAShapeLayer layer];  //設置形狀填充色  shap.fillColor = [UIColor redColor].CGColor;  _shap = shap;  //添加到最底層  [self.superview.layer insertSublayer:shap atIndex:0]; } return _shap;}//初始化-(void)setUp{ //設置圓角 self.layer.cornerRadius = self.bounds.size.width * 0.5; //設置背景文字顏色 [self setBackgroundColor:[UIColor redColor]]; [self setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal]; self.titleLabel.font = [UIFont systemFontOfSize:12]; //添加手勢 UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(pan:)]; [self addGestureRecognizer:pan]; //添加小圓 UIView *smallCircle = [[UIView alloc]initWithFrame:self.frame]; smallCircle.backgroundColor = self.backgroundColor; smallCircle.layer.cornerRadius = self.layer.cornerRadius; self.smallCircle = smallCircle; //把小圓添加到父控件中，并且在大圓下面 [self.superview insertSubview:smallCircle belowSubview:self];}-(void)pan:(UIPanGestureRecognizer*)pan{ //獲取當前點 CGPoint currentP = [pan translationInView:self]; //移動 CGPoint center = self.center; center.x += currentP.x; center.y += currentP.y; self.center = center; //復位 [pan setTranslation:CGPointZero inView:self]; //獲取兩個圓之間的距離 CGFloat distance = [self distanceWithSmallCircle:self.smallCircle bigCircle:self]; if(distance<=MAX_DIST){//只有距離不超過最大距離才計算小圓半徑  //計算小圓的半徑  //小圓半徑最小的時候是MIN_RADIUS,這個時候兩個圓達到最大距離MAX_DIST  //小圓半徑最大的時候是原始半徑，這個時候兩圓距離是0  //處于前面兩者之間的時候，小圓的半徑是：MIN_RADIUS + (原始半徑 - MIN_RADIUS)/MAX_DIST * （MAX_DIST - 當前的距離）  CGFloat smallR = self.bounds.size.width * 0.5;  smallR = MIN_RADIUS + (MAX_DIST-distance) * (smallR-MIN_RADIUS)/MAX_DIST;  //重新設置小圓的尺寸  self.smallCircle.bounds = CGRectMake(0, 0, smallR*2, smallR*2);  //重新設置小圓的半徑  self.smallCircle.layer.cornerRadius = smallR; }else{//超過了最大距離  self.smallCircle.hidden = YES;  [self.shap removeFromSuperlayer]; } //創建不規則路徑，其實就是連個圓之間連接的部分 //小圓不隱藏才創建 if(self.smallCircle.hidden == NO){  UIBezierPath *path = [self pathWithSmallCircle:self.smallCircle bigCircle:self];  self.shap.path = path.CGPath; } //當手指松開的時候 if (pan.state==UIGestureRecognizerStateEnded) {  //如果兩圓之間的距離小于最大距離，大圓復位  if (distance<MAX_DIST) {   //移除形狀圖層   [self.shap removeFromSuperlayer];   //添加一個彈性動畫   [UIView animateWithDuration:0.25 delay:0 usingSpringWithDamping:0.2 initialSpringVelocity:0 options:UIViewAnimationOptionCurveLinear animations:^{    //大圓復位    self.center = self.smallCircle.center;   } completion:^(BOOL finished) {    //小圓顯示    self.smallCircle.hidden = NO;   }];  } else {   //距離大于最大位置的時候，播放動畫，按鈕從父控件中刪除   //添加一個UIImageView 用來播放動畫   UIImageView *imageV = [[UIImageView alloc] initWithFrame:self.bounds];   [self addSubview:imageV];   //添加圖片   NSMutableArray *imageArray = [NSMutableArray array];   for (int i=1; i<=8; i++) {    NSString *imageName = [NSString stringWithFormat:@"%d",i];    UIImage *image = [UIImage imageNamed:imageName];    [imageArray addObject:image];   }   imageV.animationImages = imageArray;   //設置動畫時長   [imageV setAnimationDuration:1];   //開始動畫   [imageV startAnimating];   //一秒鐘后.把當前的按鈕從父控件當中移.   dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{    [self removeFromSuperview];   });  } }}//計算兩個圓之間的距離 使用勾股定理：兩直角邊的平方和等于斜邊的平方- (CGFloat)distanceWithSmallCircle:(UIView *)smallCircle bigCircle:(UIView *)bigCircle{ //X軸上的偏移量（就是x1-x2的值） CGFloat offsetX = bigCircle.center.x - smallCircle.center.x; //y軸上的偏移量（就是y1-y2的值） CGFloat offsetY = bigCircle.center.y - smallCircle.center.y; return sqrt(offsetX*offsetX + offsetY*offsetY);}//根據兩個圓設置一個不規的路徑- (UIBezierPath *)pathWithSmallCircle:(UIView *)smallCircle bigCircle:(UIView *)bigCircle{ CGFloat x1 = smallCircle.center.x; CGFloat y1 = smallCircle.center.y; CGFloat x2 = bigCircle.center.x; CGFloat y2 = bigCircle.center.y; CGFloat d = [self distanceWithSmallCircle:smallCircle bigCircle:self]; if (d <= 0) {  return nil; } CGFloat cosθ = (y2 - y1) / d; CGFloat sinθ = (x2 - x1) / d; CGFloat r1 = smallCircle.bounds.size.width * 0.5; CGFloat r2 = bigCircle.bounds.size.width * 0.5; CGPoint pointA = CGPointMake(x1 - r1 * cosθ, y1 + r1 * sinθ); CGPoint pointB = CGPointMake(x1 + r1 * cosθ, y1 - r1 * sinθ); CGPoint pointC = CGPointMake(x2 + r2 * cosθ, y2 - r2 * sinθ); CGPoint pointD = CGPointMake(x2 - r2 * cosθ, y2 + r2 * sinθ); CGPoint pointO = CGPointMake(pointA.x + d * 0.5 * sinθ, pointA.y + d * 0.5 * cosθ); CGPoint pointP = CGPointMake(pointB.x + d * 0.5 * sinθ, pointB.y + d * 0.5 * cosθ); UIBezierPath *path = [UIBezierPath bezierPath]; //AB [path moveToPoint:pointA]; [path addLineToPoint:pointB]; //BC(曲線) [path addQuadCurveToPoint:pointC controlPoint:pointP]; //CD [path addLineToPoint:pointD]; //DA(曲線) [path addQuadCurveToPoint:pointA controlPoint:pointO]; return path;}//清空高亮狀態-(void)setHighlighted:(BOOL)highlighted{}@end

//// ViewController.m// 03_UIView78_粒子效果2//// Created by 杞文明 on 17/7/22.// Copyright © 2017年 杞文明. All rights reserved.//#import "ViewController.h"@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad { [super viewDidLoad]; //讓View在顯示時不要把Autoresizing轉成自動布局 self.view.translatesAutoresizingMaskIntoConstraints = NO;}@end