CAShapeLayer:是CALayer的子类，负责视图的显示—>CAShapeLayer有一个神奇的属性path,给它一个path它就能变成你想要的形状，配合UIBezierPath（贝赛尔曲线），可以随意画图。
要注意的是，这里就不要用 layer.backgroundColor 这个属性了，而要使用layer.fillColor 和 layer.strokeColor ，前者代表设置这个 Layer 的填充色，后者代表设置它的边框色
1: Bezier Path :每一个连接的直线或者曲线段的集合成为subpath。一个UIBezierPath对象定义一个完整的路径包括一个或者多个subpaths
微信下拉拍小视频的那只眼睛很有趣，来模仿一下那个效果吧，它是这样的
首先你得画出这只眼睛，这是眼睛包括5个部分组
@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。
转自：放肆地使用UIBezierPath和CAShapeLayer画各种图形
学无止境，做个记录
2017-01-12-SXH
