1.创建layer
_shapeLayer= [CAShapeLayer layer];
_shapeLayer.frame=CGRectMake(0,100,375,150);
[self.view.layeraddSublayer:_shapeLayer];
_shapeLayer2= [CAShapeLayer layer];
_shapeLayer2.frame = CGRectMake(0,100,375,150);
[self.view.layer addSublayer:_shapeLayer2];
2.创建定时器
_displayLink = [CADisplayLink displayLinkWithTarget:selfselector:@selector(drawPath)];
[_displayLink addToRunLoop:[NSRunLoopmainRunLoop] forMode:NSRunLoopCommonModes];
3.drawPath方法
static doublei =0;
CGFloat A =10.f;//A振幅
CGFloat k =0;//y轴偏移
CGFloat ω = 0.03;//角速度ω变大，则波形在X轴上收缩（波形变紧密）；角速度ω变小，则波形在X轴上延展（波形变稀疏）。不等于0
CGFloat φ = 0 + i;//初相，x=0时的相位；反映在坐标系上则为图像的左右移动。
//y=Asin(ωx+φ)+k
_path= [UIBezierPath bezierPath];
_path2= [UIBezierPath bezierPath];
[_path moveToPoint:CGPointZero];
[_path2 moveToPoint:CGPointZero];
for(int i =0; i < 376; i ++) {
CGFloat x = i;
CGFloat y = A *sin(ω*x+φ)+k;
CGFloat y2 = A *cos(ω*x+φ)+k;
[_path addLineToPoint:CGPointMake(x, y)];
[_path2 addLineToPoint:CGPointMake(x, y2)];
}
[_path addLineToPoint:CGPointMake(375, -100)];
[_path addLineToPoint:CGPointMake(0, -100)];
_path.lineWidth = 1;
_shapeLayer.path = _path.CGPath;
[_path2 addLineToPoint:CGPointMake(375, -100)];
[_path2 addLineToPoint:CGPointMake(0, -100)];
_path2.lineWidth = 1;
_shapeLayer2.path = _path2.CGPath;
i +=0.1;
if(i >M_PI*2) {
i =0;//防止i越界
}
4.效果图
玩一个有趣的效果，渐变色：
demo已更新代码，这里就不贴代码了
