iOS实现贝塞尔曲线动画
作者:imJackXu
本文实例为大家分享了iOS实现贝塞尔曲线动画的具体代码,供大家参考,具体内容如下
效果如图:
仿美人相机,手势滑动隐藏顶部view。为了方便讲解,将屏幕分为几个区域,如图:
在拖动过程中:
1、拖动距离小于minMoveDistance,贝赛尔曲线发生形变
2、拖动大于minMoveDistance,整个view开始下移
在松开手时:
1、拖动距离小于minMoveDistance,未发生位移,贝塞尔曲线恢复形变
2、拖动大于minMoveDistance,小于minDisappearDistance,贝塞尔曲线恢复形变、位移回到初始位置。
3、拖动大于minDisappearDistance,向下移动隐藏view
一、根据y轴位移量确定贝塞尔路径
在拖动时曲线形变、松手时曲线恢复形变的时候都需要改变贝塞尔曲线,实际上是改变二阶贝塞尔曲线的控制点,因此写一个方法,根据传入的y轴位移量得到新的贝塞尔路径:
- (CGPathRef)getPathWithMoveDistance:(CGFloat)distance{ UIBezierPath *path = [UIBezierPath bezierPath]; CGPoint startPoint = CGPointMake(0, 0); CGPoint controlPoint = CGPointMake(self.bounds.size.width*0.5, 60+distance); CGPoint endPoint = CGPointMake(self.bounds.size.width, 0); [path moveToPoint:startPoint]; [path addQuadCurveToPoint:endPoint controlPoint:controlPoint]; [path addLineToPoint:CGPointMake(self.bounds.size.width, self.bounds.size.height)]; [path addLineToPoint:CGPointMake(0, self.bounds.size.height)]; return path.CGPath; }
二、初始化图形
初始化的时候,可以根据上一步的方法,传入位移量0,获取贝塞尔路径,并将获得的路径赋给CAShapeLayer:
- (id)initWithFrame:(CGRect)frame{ if (self = [super initWithFrame:frame]) { self.originY = frame.origin.y; [self setUpLayer]; [self addGesure]; } return self; } - (void)setUpLayer{ self.topLineLayer = [CAShapeLayer layer]; self.topLineLayer.fillColor = ColorForTheme.CGColor; self.topLineLayer.strokeColor = ColorForTheme.CGColor; self.topLineLayer.path = [self getPathWithMoveDistance:0]; [self.layer addSublayer:self.topLineLayer]; }
三、添加手势
添加UIPanGestureRecognizer拖动手势,并处理手势拖动和结束拖动的事件。
拖动时:
1、拖动距离小于minMoveDistance,只有贝赛尔曲线发生形变,调用步奏一中的方法。
2、拖动距离大于minMoveDistance,整个view开始下移
结束拖动时:
调用revertFormY:方法,传入当前在y轴上已经发生的位移量
- (void)addGesure{ if (self.gesture == nil) { self.gesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)]; } [self addGestureRecognizer:self.gesture]; } - (void)handlePan:(UIPanGestureRecognizer *)gesture{ CGFloat distanceX = [gesture translationInView:self].x; CGFloat distanceY = [gesture translationInView:self].y; if (ABS(distanceX) > ABS(distanceY)) { return; } //拖动过程 if (gesture.state == UIGestureRecognizerStateChanged) { NSLog(@"%f",distanceY); //移动少于minMoveDistance,贝赛尔曲线形变 if (distanceY > 0 && distanceY <= minMoveDistance) { self.topLineLayer.path = [self getPathWithMoveDistance:distanceY]; } //移动大于minMoveDistance,整个view下移 else if (distanceY > minMoveDistance) { self.frame = CGRectMake(0, self.originY+distanceY-minMoveDistance, self.bounds.size.width, self.bounds.size.height); } } //手势结束 if (gesture.state == UIGestureRecognizerStateEnded || gesture.state == UIGestureRecognizerStateCancelled || gesture.state == UIGestureRecognizerStateFailed) { [self removeGestureRecognizer:self.gesture]; [self revertFormY:distanceY]; } }
四、revertFormY:恢复形变方法
根据传入的y轴上的位移量,实现不同的效果:
1、y小于minMoveDistance,未发生位移,贝塞尔曲线恢复形变
2、y大于minMoveDistance,小于minDisappearDistance,贝塞尔曲线恢复形变、位移回到初始位置。
3、y大于minDisappearDistance,向下移动隐藏view
//手势结束后恢复或隐藏 -(void)revertFormY:(CGFloat)y{ //y < 最小的隐藏位移距离,未发生位移,贝塞尔曲线恢复动画 if (y < minDisappearDistance) { CAKeyframeAnimation *vibrate = [CAKeyframeAnimation animationWithKeyPath:@"path"]; vibrate.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn]; vibrate.values = @[ (id) [self getPathWithMoveDistance:y], (id) [self getPathWithMoveDistance:-(y * 0.3)], (id) [self getPathWithMoveDistance:(y * 0.2)], (id) [self getPathWithMoveDistance:-(y * 0.15)], (id) [self getPathWithMoveDistance:(y * 0.1)], (id) [self getPathWithMoveDistance:-(y * 0.07)], (id) [self getPathWithMoveDistance:(y * 0.05)], (id) [self getPathWithMoveDistance:0.0] ]; vibrate.duration = 0.5; vibrate.removedOnCompletion = NO; vibrate.fillMode = kCAFillModeForwards; vibrate.delegate = self; [self.topLineLayer addAnimation:vibrate forKey:nil]; } //y > 最小位移距离,发生了位移 if(y > minMoveDistance){ [UIView animateWithDuration:0.3 animations:^{ CGFloat endY; //向上恢复view if (y < minDisappearDistance) { endY = self.originY; } //向下隐藏view else{ endY = SCREEN_HEIGHT; } self.frame = CGRectMake(0, endY, SCREEN_WIDTH, self.frame.size.height); }]; } }
五、双击屏幕空白,消失的view从底部上移,恢复到初始位置
这个只是为了回到初始状态,根据实际需求实现。
//恢复到初始位置 - (void)comeBack{ if (self.frame.origin.y <= self.originY) { return; } [UIView animateWithDuration:0.3 animations:^{ self.frame = CGRectMake(0, self.originY, SCREEN_WIDTH, self.frame.size.height); } completion:^(BOOL finished) { [self revertFormY:10]; }]; }
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持脚本之家。