CAShapeLayer 是 CALayer 的子类,但是比 CALayer 更灵活,可以画出各种图形。
我经常将 CAShapeLayer 与UIView的 drawRect 方法混淆,因为他们都能绘制出各式各样的图形。通过NSTimer或者CADisplaylink,他们也都能显示动画效果。
现在想想,他们至少有一个重大区别:drawRect方法,是在第一次渲染或重新渲染(setNeedsDisplay)
概述
1.CAShapeLayer比CALayer多了哪些属性
2.贝塞尔曲线-Bezier
3.添加动画
4.水波纹
1.CAShapeLayer比CALayer多了哪些属性
最关键的是多了一个 path。使用它配合 UIBezierPath 该layer就可以达到神奇的效果。
demo
- (void)shapeLayerTest {
CAShapeLayer *layer = [[CAShapeLayer alloc] init];
layer.frame = CGRectMake(40, 100, 80, 50);
layer.borderColor = [UIColor blackColor].CGColor;
layer.borderWidth = 1.f;
UIBezierPath *path = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(5, 5, 70, 40)];
layer.path = path.CGPath;
layer.fillColor = [UIColor clearColor].CGColor;
layer.strokeColor = [UIColor redColor].CGColor;
[self.view.layer addSublayer:layer];
}
所有属性
// 定义要渲染的形状的路径.
@property(nullable) CGPathRef path;
// 填充 path 的颜色
@property(nullable) CGColorRef fillColor;
// 当填充填充路径(fill path)时使用。规则选项是“非零'和`偶-奇。默认“非零。
@property(copy) NSString *fillRule;
// 填充路径的描边轮廓的颜色
@property(nullable) CGColorRef strokeColor;
// 用来绘制抚摸轮廓的路径的子区域.。该值必须在范围[0,1] 0代表路径的开始和结束
@property CGFloat strokeStart;
@property CGFloat strokeEnd;
// The line width used when stroking the path. Defaults to one.
@property CGFloat lineWidth;
// The miter limit used when stroking the path. Defaults to ten.
@property CGFloat miterLimit;
@property(copy) NSString *lineCap;
@property(copy) NSString *lineJoin;
//
@property CGFloat lineDashPhase;
@property(nullable, copy) NSArray *lineDashPattern;
2.贝塞尔曲线-Bezier
- (void)quadCurve {
CAShapeLayer *layer = [[CAShapeLayer alloc] init];
layer.frame = CGRectMake(20, 100, ScreenW, ScreenH);
UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:CGPointMake(10, 50)];
[path addQuadCurveToPoint:CGPointMake(100, 50) controlPoint:CGPointMake(40, 20)];
[path moveToPoint:CGPointMake(110, 50)];
[path addCurveToPoint:CGPointMake(200, 50) controlPoint1:CGPointMake(140, 20) controlPoint2:CGPointMake(180, 80)];
layer.path = path.CGPath;
layer.fillColor = [UIColor clearColor].CGColor;
layer.strokeColor = [UIColor redColor].CGColor;
[self.view.layer addSublayer:layer];
}
3.添加动画
CAShapeLayer中有很多能进行动画的属性:strokeStart、strokeEnd、lineWidth、miterLimit、lineDashPhase。
- (void)animate1WithLayer:(CALayer *)layer {
CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
animation.fromValue = @(0);
animation.toValue = @(1);
animation.duration = 2;
[layer addAnimation:animation forKey:@""];
}
- (void)animate2WithLayer:(CAShapeLayer *)layer {
layer.strokeStart = 0.5;
layer.strokeEnd = 0.5;
CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"strokeStart"];
animation.fromValue = @(0.5);
animation.toValue = @(0);
animation.duration = 2;
[layer addAnimation:animation forKey:@""];
CABasicAnimation *animation1 = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
animation1.fromValue = @(0.5);
animation1.toValue = @(1);
animation1.duration = 2;
[layer addAnimation:animation1 forKey:@""];
// 开始layer就因为设置了strokeStart、strokeEnd为0.5,所以动画结束后就消失了。
}
4.水波纹
另外还有一种动画效果,就是让 path 一直在变。
/**
* 曲线公式
*
* f(x) = Asin(ωx+φ)+k
* y = height * sin(self.angularSpeed * x / height + self.angleOffset);
* self.angleOffset -= waveSpeed;
*/
- (CADisplayLink *)waveDisplayLink {
if (!_waveDisplayLink) {
CADisplayLink *link = [CADisplayLink displayLinkWithTarget:self selector:@selector(currentWave)];
[link addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];
_waveDisplayLink = link;
}
return _waveDisplayLink;
}
- (void)currentWave {
self.currentAngleOffset -= self.angleOffset;
CGFloat width = CGRectGetWidth(self.frame);
CGFloat height = CGRectGetHeight(self.frame);
CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL, 0, height/2);
CGFloat y = 0.f;
for (CGFloat x = 0.f; x < width; x++) {
y = height * sin(self.angularSpeed * x / height + self.currentAngleOffset);
CGPathAddLineToPoint(path, NULL, x, y);
}
CGPathAddLineToPoint(path, NULL, width, height);
CGPathAddLineToPoint(path, NULL, 0, height);
CGPathCloseSubpath(path);
self.waveShapeLayer.path = path;
CGPathRelease(path);
}
demo地址:https://github.com/taoGod/CAShapeLyer