iOS给同一个view设置四个不同的圆角

参考文章：https://blog.csdn.net/Enjolras1024/article/details/51981966

该文章讲述了整个绘制圆角的所有逻辑，本篇文章主要讲述一下，关于网上查到的绘制圆角的代码中存在的问题。

通过百度可以查到如下代码

当你将该代码复制使用后会发现，底部的两个角并没有切成圆角，而是向内凹的一个形状。而造成该问题的主要原因是：clockwise:false。

这里可以填写两个参数：YES or NO。在文章起始的参考文章中有该参数的讲解，NO是逆时针，YES是顺时针。

通过代码我们可以看到，画右下角的时候，从0PI开始，到0.5PI结束，之后逆时针去切割，就会出现向内绘制的问题。所以对于底部的两个角，我们应该是顺时针绘制切割。以下便是正确的代码

- (void)setCornerRadiusWithTopLeft:(CGFloat)topLeft topRight:(CGFloat)topRight bottomLeft:(CGFloat)bottomLeft bottomRight:(CGFloat)bottomRight{

CGFloat minX = CGRectGetMinX(self.bounds);

CGFloat minY = CGRectGetMinY(self.bounds);

CGFloat maxX = CGRectGetMaxX(self.bounds);

CGFloat maxY = CGRectGetMaxY(self.bounds);

CGFloattopLeftCenterX = minX + topLeft;

CGFloattopLeftCenterY = minY + topLeft;

CGFloattopRightCenterX = maxX - topRight;

CGFloattopRightCenterY = minY + topRight;

CGFloatbottomLeftCenterX = minX + bottomLeft;

CGFloatbottomLeftCenterY = maxY - bottomLeft;

CGFloatbottomRightCenterX = maxX - bottomRight;

CGFloatbottomRightCenterY = maxY - bottomRight;

UIBezierPath *path = [UIBezierPath bezierPath];

[pathaddArcWithCenter:CGPointMake(topLeftCenterX, topLeftCenterY) radius:topLeft startAngle:M_PI endAngle:3 * M_PI / 2.0 clockwise:YES];

[pathaddArcWithCenter:CGPointMake(topRightCenterX, topRightCenterY)radius:topRightstartAngle:3*M_PI/2.0endAngle:0clockwise:YES];

[pathaddArcWithCenter:CGPointMake(bottomRightCenterX, bottomRightCenterY)radius:bottomRightstartAngle:0endAngle:M_PI_2clockwise:YES];

[pathaddArcWithCenter:CGPointMake(bottomLeftCenterX, bottomLeftCenterY)radius:bottomLeftstartAngle:M_PI_2endAngle:M_PIclockwise:YES];

CAShapeLayer *masklayer = [[CAShapeLayer alloc]init];

masklayer.frame=self.bounds;

masklayer.path= path.CGPath;

self.layer.mask= masklayer;

}

#define M_PI 3.14159265358979323846264338327950288 /* pi */

#define M_PI_2 1.57079632679489661923132169163975144 /* pi/2 */