iOS-防止离屏渲染

UIBezierPath 贝塞尔曲线给 view 绘圆角

1、绘圆形

-(void)pd_setRadius{
    [self.superview layoutIfNeeded];   // 确保获取到 bounds

     UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:self.bounds byRoundingCorners:UIRectCornerAllCorners cornerRadii:self.bounds.size];
     CAShapeLayer *maskLayer = [[CAShapeLayer alloc]init];
     maskLayer.frame = self.bounds;
     maskLayer.path = maskPath.CGPath;
     self.layer.mask = maskLayer;
}

2、绘圆角

-(void)pd_setRadius:(float)radius{
    
    UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:self.bounds byRoundingCorners:UIRectCornerAllCorners cornerRadii:CGSizeMake(radius, radius)];
    
    CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
    maskLayer.frame = bounds;
    maskLayer.path = maskPath.CGPath;
    
    [self.layer setMask: maskLayer];
}

3、自定义绘圆角

// 给view的上方两个角 设圆角
-(void)setTopLeftTopRightCornerRadius:(float)radius{
    
    //设置所需的圆角位置以及大小
    UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:self.bounds byRoundingCorners:UIRectCornerTopLeft | UIRectCornerTopRight cornerRadii:CGSizeMake(radius, radius)];
    CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
    maskLayer.frame = self.bounds;
    maskLayer.path = maskPath.CGPath;
    self.layer.mask = maskLayer;
    
}

// 参数可选值
typedef NS_OPTIONS(NSUInteger, UIRectCorner) {
    UIRectCornerTopLeft     = 1 << 0,
    UIRectCornerTopRight    = 1 << 1,
    UIRectCornerBottomLeft  = 1 << 2,
    UIRectCornerBottomRight = 1 << 3,
    UIRectCornerAllCorners  = ~0UL
};

使用绘图技术 直接给image切圆角

 - (UIImage *)imageWithCornerRadius:(CGFloat)radius size:(CGSize)size {
    CGRect rect = (CGRect){0.f, 0.f, size};
    UIGraphicsBeginImageContextWithOptions(size, NO, UIScreen.mainScreen.scale);
    CGContextAddPath(UIGraphicsGetCurrentContext(), [UIBezierPath bezierPathWithRoundedRect:rect cornerRadius:radius].CGPath);
        CGContextClip(UIGraphicsGetCurrentContext());
    [self drawInRect:rect];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
    return image;
}