放肆的使用 UIBezierPath 和 CAShapeLayer 画各种图形
thwi1315
7年前
<p>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。</p> <h2>杂谈</h2> <p>在 CAShapeLayer 中，也可以像 CALayer 一样指定它的 frame 来画，就像这样：</p> <pre> <code class="language-objectivec">letlayer = CAShapeLayer() layer.frame = CGRectMake(110, 100, 150, 100) layer.backgroundColor = UIColor.blackColor().CGColor view.layer.addSublayer(layer) </code></pre> <p>然后你就会得到如图这样的黑色矩形</p> <p><img src="https://simg.open-open.com/show/f29132c30b1969f1dc78d0fa748e4ed9.png"></p> <p>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。</p> <p>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：</p> <pre> <code class="language-objectivec">letpath = UIBezierPath(rect: CGRectMake(110, 100, 150, 100)) letlayer = CAShapeLayer() layer.path = path.CGPath layer.fillColor = UIColor.blackColor().CGColor view.layer.addSublayer(layer) </code></pre> <p>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</p> <pre> <code class="language-objectivec">layer.fillColor = UIColor.clearColor().CGColor layer.strokeColor = UIColor.blackColor().CGColor </code></pre> <p>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</p> <p><img src="https://simg.open-open.com/show/ccb01c27173ae5a520618ab5564d83d3.png"></p> <h2>玩一下UIBezierPath</h2> <p>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</p> <pre> <code class="language-objectivec">letpath = UIBezierPath(roundedRect: CGRectMake(110, 100, 150, 100), cornerRadius: 50) letlayer = CAShapeLayer() layer.path = path.CGPath layer.fillColor = UIColor.clearColor().CGColor layer.strokeColor = UIColor.blackColor().CGColor </code></pre> <p><img src="https://simg.open-open.com/show/cec8faaf91a85ea6db13c8d5d0146389.png"></p> <p>还可以指定起始角和半径画圆</p> <pre> <code class="language-objectivec">letradius: CGFloat = 60.0 letstartAngle: CGFloat = 0.0 letendAngle: CGFloat = CGFloat(M_PI * 2) letpath = UIBezierPath(arcCenter: view.center, radius: radius, startAngle: startAngle, endAngle: endAngle, clockwise: true) letlayer = CAShapeLayer() layer.path = path.CGPath layer.fillColor = UIColor.clearColor().CGColor layer.strokeColor = UIColor.blackColor().CGColor </code></pre> <p><img src="https://simg.open-open.com/show/06e3823f174125e54226666f56c31a68.png"></p> <p>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</p> <p><img src="https://simg.open-open.com/show/811043df5d873adf88859fe831e5ee90.png"></p> <h2>怎么画曲线</h2> <p>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</p> <pre> <code class="language-objectivec">letstartPoint = CGPointMake(50, 300) letendPoint = CGPointMake(300, 300) letcontrolPoint = CGPointMake(170, 200) letlayer1 = CALayer() layer1.frame = CGRectMake(startPoint.x, startPoint.y, 5, 5) layer1.backgroundColor = UIColor.redColor().CGColor letlayer2 = CALayer() layer2.frame = CGRectMake(endPoint.x, endPoint.y, 5, 5) layer2.backgroundColor = UIColor.redColor().CGColor letlayer3 = CALayer() layer3.frame = CGRectMake(controlPoint.x, controlPoint.y, 5, 5) layer3.backgroundColor = UIColor.redColor().CGColor letpath = UIBezierPath() letlayer = 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) </code></pre> <p>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</p> <p><img src="https://simg.open-open.com/show/380aa9f57543b181b5af0508ac59ceb6.png"></p> <p>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</p> <p>这样它会是这个样子</p> <p><img src="https://simg.open-open.com/show/9359c924ecc4a2a3251c7d4a3aafe1a9.png"></p> <h2>再来说说 CAShapeLayer</h2> <p>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</p> <p><img src="https://simg.open-open.com/show/21036f1af18fe3f76599f94cfc3f7ae1.gif"></p> <p>demo1.gif</p> <p><img src="https://simg.open-open.com/show/4a250105e7a0e08ecc5f4f474414a7ef.gif"></p> <p>demo2.gif</p> <p><img src="https://simg.open-open.com/show/0b86ee906bd38ccf1ecac522cabb578a.gif"></p> <p>demo3.gif</p> <p>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。</p> <p>示例代码</p> <pre> <code class="language-objectivec"> private funcanimation1() { letanimation = CABasicAnimation(keyPath: "strokeEnd") animation.fromValue = 0 animation.toValue = 1 animation.duration = 2 layer.addAnimation(animation, forKey: "") } private funcanimation2() { layer.strokeStart = 0.5 layer.strokeEnd = 0.5 letanimation = CABasicAnimation(keyPath: "strokeStart") animation.fromValue = 0.5 animation.toValue = 0 animation.duration = 2 letanimation2 = CABasicAnimation(keyPath: "strokeEnd") animation2.fromValue = 0.5 animation2.toValue = 1 animation2.duration = 2 layer.addAnimation(animation, forKey: "") layer.addAnimation(animation2, forKey: "") } private funcanimation3() { letanimation = CABasicAnimation(keyPath: "lineWidth") animation.fromValue = 1 animation.toValue = 10 animation.duration = 2 layer.addAnimation(animation, forKey: "") } </code></pre> <h2>应用一下</h2> <p>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</p> <p><img src="https://simg.open-open.com/show/6afd5c845f024ac1c9381addf4d40638.png"></p> <p>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</p> <pre> <code class="language-objectivec">letfinalSize = CGSizeMake(CGRectGetWidth(view.frame), 400) letlayerHeight = finalSize.height * 0.2 letlayer = CAShapeLayer() letbezier = 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) </code></pre> <p>就能画出这样的形状来</p> <p><img src="https://simg.open-open.com/show/3297d1d2ac6c2d9fa918371882446009.png"></p> <p>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</p> <p><img src="https://simg.open-open.com/show/8e1cbe1e9cd657abafa0318437b4bb7d.gif"></p> <p>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）</p> <pre> <code class="language-objectivec">@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; </code></pre> <p>然后，还是通过 UIBezierPath 和 CAShapeLayer 这样的老套路来画，代码较多</p> <pre> <code class="language-objectivec">- (CAShapeLayer *)eyeFirstLightLayer { if (!_eyeFirstLightLayer) { _eyeFirstLightLayer = [CAShapeLayerlayer]; CGPointcenter = CGPointMake(CGRectGetWidth(self.frame) / 2, CGRectGetHeight(self.frame) / 2); UIBezierPath *path = [UIBezierPathbezierPathWithArcCenter: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 = [UIColorblackColor].CGColor; _eyeFirstLightLayer.lineWidth = 5.f; _eyeFirstLightLayer.path = path.CGPath; _eyeFirstLightLayer.fillColor = [UIColorclearColor].CGColor; _eyeFirstLightLayer.strokeColor = [UIColorwhiteColor].CGColor; } return _eyeFirstLightLayer; } - (CAShapeLayer *)eyeSecondLightLayer { if (!_eyeSecondLightLayer) { _eyeSecondLightLayer = [CAShapeLayerlayer]; CGPointcenter = CGPointMake(CGRectGetWidth(self.frame) / 2, CGRectGetHeight(self.frame) / 2); UIBezierPath *path = [UIBezierPathbezierPathWithArcCenter: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 = [UIColorblackColor].CGColor; _eyeSecondLightLayer.lineWidth = 5.f; _eyeSecondLightLayer.path = path.CGPath; _eyeSecondLightLayer.fillColor = [UIColorclearColor].CGColor; _eyeSecondLightLayer.strokeColor = [UIColorwhiteColor].CGColor; } return _eyeSecondLightLayer; } - (CAShapeLayer *)eyeballLayer { if (!_eyeballLayer) { _eyeballLayer = [CAShapeLayerlayer]; CGPointcenter = CGPointMake(CGRectGetWidth(self.frame) / 2, CGRectGetHeight(self.frame) / 2); UIBezierPath *path = [UIBezierPathbezierPathWithArcCenter: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 = [UIColorblackColor].CGColor; _eyeballLayer.lineWidth = 1.f; _eyeballLayer.path = path.CGPath; _eyeballLayer.fillColor = [UIColorclearColor].CGColor; _eyeballLayer.strokeColor = [UIColorwhiteColor].CGColor; _eyeballLayer.anchorPoint = CGPointMake(0.5, 0.5); } return _eyeballLayer; } - (CAShapeLayer *)topEyesocketLayer { if (!_topEyesocketLayer) { _topEyesocketLayer = [CAShapeLayerlayer]; CGPointcenter = CGPointMake(CGRectGetWidth(self.frame) / 2, CGRectGetHeight(self.frame) / 2); UIBezierPath *path = [UIBezierPathbezierPath]; [pathmoveToPoint:CGPointMake(0, CGRectGetHeight(self.frame) / 2)]; [pathaddQuadCurveToPoint:CGPointMake(CGRectGetWidth(self.frame), CGRectGetHeight(self.frame) / 2) controlPoint:CGPointMake(CGRectGetWidth(self.frame) / 2, center.y - center.y - 20)]; _topEyesocketLayer.borderColor = [UIColorblackColor].CGColor; _topEyesocketLayer.lineWidth = 1.f; _topEyesocketLayer.path = path.CGPath; _topEyesocketLayer.fillColor = [UIColorclearColor].CGColor; _topEyesocketLayer.strokeColor = [UIColorwhiteColor].CGColor; } return _topEyesocketLayer; } - (CAShapeLayer *)bottomEyesocketLayer { if (!_bottomEyesocketLayer) { _bottomEyesocketLayer = [CAShapeLayerlayer]; CGPointcenter = CGPointMake(CGRectGetWidth(self.frame) / 2, CGRectGetHeight(self.frame) / 2); UIBezierPath *path = [UIBezierPathbezierPath]; [pathmoveToPoint:CGPointMake(0, CGRectGetHeight(self.frame) / 2)]; [pathaddQuadCurveToPoint:CGPointMake(CGRectGetWidth(self.frame), CGRectGetHeight(self.frame) / 2) controlPoint:CGPointMake(CGRectGetWidth(self.frame) / 2, center.y + center.y + 20)]; _bottomEyesocketLayer.borderColor = [UIColorblackColor].CGColor; _bottomEyesocketLayer.lineWidth = 1.f; _bottomEyesocketLayer.path = path.CGPath; _bottomEyesocketLayer.fillColor = [UIColorclearColor].CGColor; _bottomEyesocketLayer.strokeColor = [UIColorwhiteColor].CGColor; } return _bottomEyesocketLayer; } </code></pre> <p>然后更改一下某些属性的值，方便稍后的动画</p> <pre> <code class="language-objectivec">- (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; } </code></pre> <p>最后根据 UIScrollView 的 contentOffset 来控制各种属性，办法较笨，但管用。</p> <pre> <code class="language-objectivec">- (void)animationWith:(CGFloat)y { CGFloatflag = self.frame.origin.y * 2.f - 20.f; if (y 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 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; } } } </code></pre> <h2>最后</h2> <p>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。</p> <h2>微信Demo</h2> <p>代码</p> <p><a href="/misc/goto?guid=4959732765977224716" rel="nofollow,noindex">https://github.com/J0HDev/WXVideo</a></p> <p> </p> <p>来自：http://ios.jobbole.com/92213/</p> <p> </p>