iOS 圆角设置避免离屏渲染

找了很多文章终于发现一个差不多的，特别记录一下

www.jianshu.com/p/e879aeff9…

设置UIView

- (UIImageView *)dlj_addRounderCornerWithRadius:(CGFloat)radius size:(CGSize)size
{
    UIGraphicsBeginImageContextWithOptions(size, NO, 0);
    CGContextRef cxt = UIGraphicsGetCurrentContext();
    
    CGContextSetFillColorWithColor(cxt, LBWhiteColor.CGColor);
    CGContextSetStrokeColorWithColor(cxt, LBWhiteColor.CGColor);
    
    CGContextMoveToPoint(cxt, size.width, size.height-radius);
    CGContextAddArcToPoint(cxt, size.width, size.height, size.width-radius, size.height, radius);//右下角
    CGContextAddArcToPoint(cxt, 0, size.height, 0, size.height-radius, radius);//左下角
    CGContextAddArcToPoint(cxt, 0, 0, radius, 0, radius);//左上角
    CGContextAddArcToPoint(cxt, size.width, 0, size.width, radius, radius);//右上角
    CGContextClosePath(cxt);
    CGContextDrawPath(cxt, kCGPathFillStroke);
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, size.width, size.height)];
    [imageView setImage:image];
    
    return imageView;
}

设置ImageView

- (UIImage*)imageAddCornerWithRadius:(CGFloat)radius andSize:(CGSize)size{
    CGRect rect = CGRectMake(0, 0, size.width, size.height);
    
    UIGraphicsBeginImageContextWithOptions(size, NO, [UIScreen mainScreen].scale);
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    UIBezierPath * path = [UIBezierPath bezierPathWithRoundedRect:rect byRoundingCorners:UIRectCornerAllCorners cornerRadii:CGSizeMake(radius, radius)];
    CGContextAddPath(ctx,path.CGPath);
    CGContextClip(ctx);
    [self drawInRect:rect];
    CGContextDrawPath(ctx, kCGPathFillStroke);
    UIImage * newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}