微信小视频下拉时眼睛动画
###Demo
###Basic
首先你得画出这只眼睛，这是眼睛包括5个部分组成
@property (strong, nonatomic) CAShapeLayer *eyeFirstLightLayer;
@property (strong, nonatomic) CAShapeLayer *eyeSecondLightLayer;
@property (strong, nonatomic) CAShapeLayer *eyeballLayer;
@property (strong, nonatomic) CAShapeLayer *topEyesocketLayer;
@property (strong, nonatomic) CAShapeLayer *bottomEyesocketLayer;
然后，还是通过 UIBezierPath 和 CAShapeLayer 这样的老套路来画，代码较多
- (CAShapeLayer *)eyeFirstLightLayer {
if (!_eyeFirstLightLayer) {
_eyeFirstLightLayer = [CAShapeLayer layer];
CGPoint center = CGPointMake(CGRectGetWidth(self.frame) / 2, CGRectGetHeight(self.frame) / 2);
UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:center
radius:CGRectGetWidth(self.frame) * 0.2
startAngle:(230.f / 180.f) * M_PI
endAngle:(265.f / 180.f) * M_PI
clockwise:YES];
_eyeFirstLightLayer.borderColor = [UIColor blackColor].CGColor;
_eyeFirstLightLayer.lineWidth = 5.f;
_eyeFirstLightLayer.path = path.CGPath;
_eyeFirstLightLayer.fillColor = [UIColor clearColor].CGColor;
_eyeFirstLightLayer.strokeColor = [UIColor whiteColor].CGColor;
}
return _eyeFirstLightLayer;
}
- (CAShapeLayer *)eyeSecondLightLayer {
if (!_eyeSecondLightLayer) {
_eyeSecondLightLayer = [CAShapeLayer layer];
CGPoint center = CGPointMake(CGRectGetWidth(self.frame) / 2, CGRectGetHeight(self.frame) / 2);
UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:center
radius:CGRectGetWidth(self.frame) * 0.2
startAngle:(211.f / 180.f) * M_PI
endAngle:(220.f / 180.f) * M_PI
clockwise:YES];
_eyeSecondLightLayer.borderColor = [UIColor blackColor].CGColor;
_eyeSecondLightLayer.lineWidth = 5.f;
_eyeSecondLightLayer.path = path.CGPath;
_eyeSecondLightLayer.fillColor = [UIColor clearColor].CGColor;
_eyeSecondLightLayer.strokeColor = [UIColor whiteColor].CGColor;
}
return _eyeSecondLightLayer;
}
- (CAShapeLayer *)eyeballLayer {
if (!_eyeballLayer) {
_eyeballLayer = [CAShapeLayer layer];
CGPoint center = CGPointMake(CGRectGetWidth(self.frame) / 2, CGRectGetHeight(self.frame) / 2);
UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:center
radius:CGRectGetWidth(self.frame) * 0.3
startAngle:(0.f / 180.f) * M_PI
endAngle:(360.f / 180.f) * M_PI
clockwise:YES];
_eyeballLayer.borderColor = [UIColor blackColor].CGColor;
_eyeballLayer.lineWidth = 1.f;
_eyeballLayer.path = path.CGPath;
_eyeballLayer.fillColor = [UIColor clearColor].CGColor;
_eyeballLayer.strokeColor = [UIColor whiteColor].CGColor;
_eyeballLayer.anchorPoint = CGPointMake(0.5, 0.5);
}
return _eyeballLayer;
}
- (CAShapeLayer *)topEyesocketLayer {
if (!_topEyesocketLayer) {
_topEyesocketLayer = [CAShapeLayer layer];
CGPoint center = CGPointMake(CGRectGetWidth(self.frame) / 2, CGRectGetHeight(self.frame) / 2);
UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:CGPointMake(0, CGRectGetHeight(self.frame) / 2)];
[path addQuadCurveToPoint:CGPointMake(CGRectGetWidth(self.frame), CGRectGetHeight(self.frame) / 2)
controlPoint:CGPointMake(CGRectGetWidth(self.frame) / 2, center.y - center.y - 20)];
_topEyesocketLayer.borderColor = [UIColor blackColor].CGColor;
_topEyesocketLayer.lineWidth = 1.f;
_topEyesocketLayer.path = path.CGPath;
_topEyesocketLayer.fillColor = [UIColor clearColor].CGColor;
_topEyesocketLayer.strokeColor = [UIColor whiteColor].CGColor;
}
return _topEyesocketLayer;
}
- (CAShapeLayer *)bottomEyesocketLayer {
if (!_bottomEyesocketLayer) {
_bottomEyesocketLayer = [CAShapeLayer layer];
CGPoint center = CGPointMake(CGRectGetWidth(self.frame) / 2, CGRectGetHeight(self.frame) / 2);
UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:CGPointMake(0, CGRectGetHeight(self.frame) / 2)];
[path addQuadCurveToPoint:CGPointMake(CGRectGetWidth(self.frame), CGRectGetHeight(self.frame) / 2)
controlPoint:CGPointMake(CGRectGetWidth(self.frame) / 2, center.y + center.y + 20)];
_bottomEyesocketLayer.borderColor = [UIColor blackColor].CGColor;
_bottomEyesocketLayer.lineWidth = 1.f;
_bottomEyesocketLayer.path = path.CGPath;
_bottomEyesocketLayer.fillColor = [UIColor clearColor].CGColor;
_bottomEyesocketLayer.strokeColor = [UIColor whiteColor].CGColor;
}
return _bottomEyesocketLayer;
}
然后更改一下某些属性的值，方便稍后的动画
- (void)setupAnimation {
self.eyeFirstLightLayer.lineWidth = 0.f;
self.eyeSecondLightLayer.lineWidth = 0.f;
self.eyeballLayer.opacity = 0.f;
_bottomEyesocketLayer.strokeStart = 0.5f;
_bottomEyesocketLayer.strokeEnd = 0.5f;
_topEyesocketLayer.strokeStart = 0.5f;
_topEyesocketLayer.strokeEnd = 0.5f;
}
最后根据 UIScrollView 的 contentOffset 来控制各种属性，办法较笨，但管用。
- (void)animationWith:(CGFloat)y {
CGFloat flag = self.frame.origin.y * 2.f - 20.f;
if (y < flag) {
if (self.eyeFirstLightLayer.lineWidth < 5.f) {
self.eyeFirstLightLayer.lineWidth += 1.f;
self.eyeSecondLightLayer.lineWidth += 1.f;
}
}
if(y < flag - 20) {
if (self.eyeballLayer.opacity <= 1.0f) {
self.eyeballLayer.opacity += 0.1f;
}
}
if (y < flag - 40) {
if (self.topEyesocketLayer.strokeEnd < 1.f && self.topEyesocketLayer.strokeStart > 0.f) {
self.topEyesocketLayer.strokeEnd += 0.1f;
self.topEyesocketLayer.strokeStart -= 0.1f;
self.bottomEyesocketLayer.strokeEnd += 0.1f;
self.bottomEyesocketLayer.strokeStart -= 0.1f;
}
}
if (y > flag - 40) {
if (self.topEyesocketLayer.strokeEnd > 0.5f && self.topEyesocketLayer.strokeStart < 0.5f) {
self.topEyesocketLayer.strokeEnd -= 0.1f;
self.topEyesocketLayer.strokeStart += 0.1f;
self.bottomEyesocketLayer.strokeEnd -= 0.1f;
self.bottomEyesocketLayer.strokeStart += 0.1f;
}
}
if (y > flag - 20) {
if (self.eyeballLayer.opacity >= 0.0f) {
self.eyeballLayer.opacity -= 0.1f;
}
}
if (y > flag) {
if (self.eyeFirstLightLayer.lineWidth > 0.f) {
self.eyeFirstLightLayer.lineWidth -= 1.f;
self.eyeSecondLightLayer.lineWidth -= 1.f;
}
}
}