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放肆的使用UIBezierPath和CAShapeLayer画各种图形

2015-11-27 12:37 J0hnnny

放肆的使用UIBezierPath和CAShapeLayer画各种图形


CAShapeLayer 是 CALayer 的子类,但是比 CALayer 更灵活,可以画出各种图形,当然,你也可以使用其他方式来画,随你。

杂谈

在 CAShapeLayer 中,也可以像 CALayer 一样指定它的 frame 来画,就像这样:

let layer = CAShapeLayer()
layer.frame = CGRectMake(110, 100, 150, 100)
layer.backgroundColor = UIColor.blackColor().CGColor

view.layer.addSublayer(layer)


然后你就会得到如图这样的黑色矩形


但是,CAShapeLayer 有一个神奇的属性 path 用这个属性配合上 UIBezierPath 这个类就可以达到超神的效果。

UIBezierPath 顾名思义,这是用贝塞尔曲线的方式来构建一段弧线,你可以用任意条弧线来组成你想要的形状,比如,你想用它来和上面一样画一个矩形,那就可以这样子来做:

let path = UIBezierPath(rect: CGRectMake(110, 100, 150, 100))
let layer = CAShapeLayer()
layer.path = path.CGPath

layer.fillColor = UIColor.blackColor().CGColor

view.layer.addSublayer(layer)


要注意的是,这里就不要用backgroundColor 这个属性了,而要使用 fillColor 和 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

layer.fillColor = UIColor.clearColor().CGColor

layer.strokeColor = UIColor.blackColor().CGColor


可以试一下把上面代码设置颜色的部分改成这个样子,那么运行程序的时候就会是这种样子


玩一下UIBezierPath

在说回 UIBezierPath ,在 UIBezierPath 的 init 方法中,就有很多方便你画各种图形的方法,比如你可以画一个带圆角的图形

let path = UIBezierPath(roundedRect: CGRectMake(110, 100, 150, 100), cornerRadius: 50)
let layer = CAShapeLayer()
layer.path = path.CGPathlayer.fillColor = UIColor.clearColor().CGColor

layer.strokeColor = UIColor.blackColor().CGColor



还可以指定起始角和半径画圆

let radius: CGFloat = 60.0

let startAngle: CGFloat = 0.0

let endAngle: CGFloat = CGFloat(M_PI * 2)
let path = UIBezierPath(arcCenter: view.center, radius: radius, startAngle: startAngle, endAngle: endAngle, clockwise: true)
let layer = CAShapeLayer()
layer.path = path.CGPath

layer.fillColor = UIColor.clearColor().CGColor

layer.strokeColor = UIColor.blackColor().CGColor



在这里涉及到角度的问题,起始角和结束角,这里的角度使使用弧度制来表示,这里我收藏了一张图片,以方便参考


怎么画曲线

贝塞尔曲线的画法是由起点、终点、控制点三个参数来画的,为了解释清楚这个点,我写了几行代码来解释它


let startPoint = CGPointMake(50, 300)
let endPoint = CGPointMake(300, 300)
let controlPoint = CGPointMake(170, 200)

let layer1 = CALayer()
layer1.frame = CGRectMake(startPoint.x, startPoint.y, 5, 5)
layer1.backgroundColor = UIColor.redColor().CGColor

let layer2 = CALayer()
layer2.frame = CGRectMake(endPoint.x, endPoint.y, 5, 5)
layer2.backgroundColor = UIColor.redColor().CGColor

let layer3 = CALayer()
layer3.frame = CGRectMake(controlPoint.x, controlPoint.y, 5, 5)
layer3.backgroundColor = UIColor.redColor().CGColor

let path = UIBezierPath()
let layer = CAShapeLayer()

path.moveToPoint(startPoint)
path.addQuadCurveToPoint(endPoint, controlPoint: controlPoint)

layer.path = path.CGPath

layer.fillColor = UIColor.clearColor().CGColor

layer.strokeColor = UIColor.blackColor().CGColor

view.layer.addSublayer(layer)
view.layer.addSublayer(layer1)
view.layer.addSublayer(layer2)
view.layer.addSublayer(layer3)


我很随意的定义了三个点,为了清楚显示它们的位置,我放了三个矩形在上面以便观察,然后调用 path.moveToPoint(startPoint) 让它移动到起始点,然后调用path.addQuadCurveToPoint(endPoint, controlPoint: controlPoint) 这个方法告诉它结束点和控制点,这样它就能画出一条有弧度的线条了,如果把fillColor设置一个颜色,那么它就会变成一个很丑的形状了,示例图如下


控制点决定了它的曲率,曲线的顶点不等于控制点的位置,具体可以看一下贝塞尔曲线的定义,你还可以使用两个控制点来画,两个控制点可以使用方法 path.addCurveToPoint(endPoint, controlPoint1: controlPoint, controlPoint2: controlPoint2)来搞定

这样它会是这个样子


再来说说 CAShapeLayer

CAShapeLayer 是个神奇的东西,给它一个path它就能变成你想要的形状,它还有很多可以玩的地方。综合使用可以组合成不同的动画,比如下面这样







这三个动画就是使用了 strokeEnd strokeStart lineWidth 三个属性,第一个动画用了strokeEnd这个属性的值范围是0-1,动画显示了从0到1之间每一个值对这条曲线的影响,strokeStart的方法则是相反的,如果把这两个值首先都设置成0.5然后慢慢改变成0和1的时候就会变成第二个动画,配合lineWidth则曲线会慢慢变粗,这里的很多属性都是支持动画的。

示例代码


private func animation1() {
let animation = CABasicAnimation(keyPath: "strokeEnd")

animation.fromValue = 0
animation.toValue = 1
animation.duration = 2
layer.addAnimation(animation, forKey: "")
}

private func animation2() {

layer.strokeStart = 0.5
layer.strokeEnd = 0.5

let animation = CABasicAnimation(keyPath: "strokeStart")

animation.fromValue = 0.5
animation.toValue = 0
animation.duration = 2

let animation2 = CABasicAnimation(keyPath: "strokeEnd")
animation2.fromValue = 0.5
animation2.toValue = 1
animation2.duration = 2

layer.addAnimation(animation, forKey: "")
layer.addAnimation(animation2, forKey: "")
}

private func animation3() {
let animation = CABasicAnimation(keyPath: "lineWidth")
animation.fromValue = 1
animation.toValue = 10
animation.duration = 2
layer.addAnimation(animation, forKey: "")
}


应用一下

前一阵子在仿时光网这个APP,其中有一个Layer的形状很怪异,是这样的


很明显它可以用 CAShapeLayer + UIBezierPath 来做,思路大概是这样,先移动到左上方的位置,然后向下划线,然后往右划线,然后往上划线,还剩一个盖子,这个盖子就用一个控制点控制曲率,非常简单,代码如下


let finalSize = CGSizeMake(CGRectGetWidth(view.frame), 400)
let layerHeight = finalSize.height * 0.2let layer = CAShapeLayer()
let bezier = UIBezierPath()
bezier.moveToPoint(CGPointMake(0, finalSize.height - layerHeight))
bezier.addLineToPoint(CGPointMake(0, finalSize.height - 1))
bezier.addLineToPoint(CGPointMake(finalSize.width, finalSize.height - 1))
bezier.addLineToPoint(CGPointMake(finalSize.width, finalSize.height - layerHeight))
bezier.addQuadCurveToPoint(CGPointMake(0,finalSize.height - layerHeight),
controlPoint: CGPointMake(finalSize.width / 2, (finalSize.height - layerHeight) - 40))
layer.path = bezier.CGPath

layer.fillColor = UIColor.blackColor().CGColor

view.layer.addSublayer(layer)


就能画出这样的形状来


再来一个复杂点的,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个部分组成(这个是用OC写的)


@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;
}
}
}


最后

总之使用 UIbezierPath 和 CAShapeLayer 可以画出你想要的任何形状,没有它做不到,只有你想不到,搞定了它们你就可以轻松定制你想要的任何控件了。



横屏 或“阅读原文”代码显示效果更好



 
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