CAGradientLayer & CAShapeLay

CAGradientLayer:渐变色结构

• 属性解析:

    CAGradientLayer * gtLayer = [CAGradientLayer layer];
    gtLayer.frame = view.bounds;
    [gtLayer setColors:[NSArray arrayWithObjects:(id)[UIColor redColor].CGColor,(id)[UIColor blackColor].CGColor,(id)[UIColor blueColor].CGColor, nil]];
    //location表示在这个位置要开始进行颜色渐变
    [gtLayer setLocations:@[@(0.5),@(0.6),@0.7]];
    //颜色起始点
    [gtLayer setStartPoint:CGPointMake(0, 0.5)];
    //颜色结束点
    [gtLayer setEndPoint:CGPointMake(1, 0.5)];
    [view.layer addSublayer:gtLayer];
  

* startPoint:默认点是(0.5,0);
* endPoint:默认点是(0.5,1);

####CAGradientLayer:可以为它添加动画来实现一些效果;
* 简单实现:

![ColorShape.gif](https://img.haomeiwen.com/i1361866/078b5978ba84f40d.gif?imageMogr2/auto-orient/strip)
这个动画是用过使用环形CAShapeLayer进行遮罩,添加CABasicAnimation实现;
代码:

self.view.backgroundColor = [UIColor blackColor];

CAGradientLayer * gtLayer = [CAGradientLayer layer];
gtLayer.frame = self.view.bounds;
[gtLayer setColors:[NSArray arrayWithObjects:(id)[UIColor redColor].CGColor,(id)[UIColor whiteColor].CGColor,(id)[UIColor redColor].CGColor, nil]];
self.location = -0.1;
//location表示在这个位置要开始进行颜色渐变
[gtLayer setLocations:@[@(-0.2),@(-0.1),@(0)]];
//颜色起始点
[gtLayer setStartPoint:CGPointMake(0, 0)];
//颜色结束点
[gtLayer setEndPoint:CGPointMake(1, 0)];
[self.view.layer addSublayer:gtLayer];
self.gl= gtLayer;

//创建一个
CAShapeLayer * shapeL = [CAShapeLayer layer];

UIBezierPath * pathS = [UIBezierPath bezierPathWithArcCenter:CGPointZero radius:100 startAngle:0 endAngle:M_PI*2 clockwise:YES];
shapeL.path = pathS.CGPath;
//默认相当于中心
shapeL.position = self.view.center;
shapeL.fillColor = [UIColor clearColor].CGColor;

shapeL.strokeColor = [UIColor redColor].CGColor;
[self.view.layer addSublayer:shapeL];
shapeL.strokeEnd = 1.f;
gtLayer.mask = shapeL;

[NSTimer scheduledTimerWithTimeInterval:1.5 target:self selector:@selector(Roll) userInfo:nil repeats:YES];

• (void)Roll
  {
  CABasicAnimation * animationC = [CABasicAnimation animationWithKeyPath:@"locations"];
  animationC.fromValue = @[@(-0.2),@(-0.1),@0];
  animationC.toValue = @[@1,@1.1,@1.2];
  animationC.duration = 1.5;
  [self.gl addAnimation:animationC forKey:nil];
  }

***
### CAShapeLayer
* 效果图:

![ShapeLayer.gif](https://img.haomeiwen.com/i1361866/580fbc383c320998.gif?imageMogr2/auto-orient/strip)

代码:

UIView * view = [[UIView alloc] init];
view.frame = CGRectMake(100, 100, 200, 200);
view.layer.masksToBounds = YES;
view.layer.cornerRadius = 50;
view.alpha = 0.5;
[self.view addSubview:view];

UIBezierPath * path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(50, 50) radius:50.0f startAngle:0 endAngle:M_PI * 2 clockwise:YES];

CAShapeLayer * shapeLayer= [CAShapeLayer layer];
shapeLayer.frame = CGRectMake(15, 15, 0, 0);
//边缘颜色
shapeLayer.strokeColor = [UIColor blackColor].CGColor;
//填充颜色
shapeLayer.fillColor = [UIColor clearColor].CGColor;
//端点处的样式
shapeLayer.lineCap = @"round";
//轨迹
shapeLayer.path = path.CGPath;

//画虚线的时候用
//从10的坐标点开始显示
//    shapeLayer.lineDashPhase = 10;
//画10个点,空20格点,画20个点,虚10个点,画20个点,,,这样这三个数一直循环
//    shapeLayer.lineDashPattern = @[@10,@20,@20];


shapeLayer.lineWidth = 10.0f;
//开始点
shapeLayer.strokeStart = 0.0;
//结束点
shapeLayer.strokeEnd = 0.8f;
self.start = 0.0;
self.end = 0.8;

self.shapeL = shapeLayer;
[view.layer addSublayer:shapeLayer];
[view.layer setMask:shapeLayer];

dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(3.0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
    shapeLayer.speed = 0.1;
    shapeLayer.strokeStart = 0.5;
    shapeLayer.strokeEnd= 0.9;
    shapeLayer.lineWidth = 6.0f;
});

CABasicAnimation * basicA = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
basicA.duration = 1.0f;
basicA.fromValue = @(0.0f);
basicA.toValue = @(0.8f);
[shapeLayer addAnimation:basicA forKey:@"anyone"];

CAGradientLayer * colorLager = [CAGradientLayer layer];
colorLager.frame =CGRectMake(0, 0, view.bounds.size.width+15, view.bounds.size.height+15);

[colorLager setColors:[NSArray arrayWithObjects:(id)[UIColor redColor].CGColor,(id)[UIColor cyanColor].CGColor,(id)[UIColor magentaColor].CGColor,nil]];
colorLager.shadowPath = path.CGPath;
[colorLager setLocations:@[@(0.2),@(0.3),@(0.8)]];
[colorLager setStartPoint:CGPointMake(0, 0)];
[colorLager setEndPoint:CGPointMake(1, 1)];

[view.layer addSublayer:colorLager];