创建圆角的图片遮罩, insertSubview 到底部

oc_draw_CornerimageMaskMask.codesnippest

- (UIImage *)createRoundedCornerImageWithRadius:(CGFloat)radius outerSize:(CGSize)outerSize innerSize:(CGSize)innerSize  fillColor:(UIColor *)fillColor {
    UIGraphicsBeginImageContextWithOptions(outerSize, false, [UIScreen mainScreen].scale);
    CGContextRef currentContext = UIGraphicsGetCurrentContext();
    
    UIBezierPath *bezierPath = [[UIBezierPath alloc] init];
    
    CGFloat xOffset = (outerSize.width - innerSize.width) / 2;
    CGFloat yOffset = (outerSize.height - innerSize.height) / 2;
    
    CGPoint hLeftUpPoint = CGPointMake(xOffset + radius, yOffset);
    CGPoint hRightUpPoint = CGPointMake(outerSize.width - xOffset - radius, yOffset);
    CGPoint hLeftDownPoint = CGPointMake(xOffset + radius, outerSize.height - yOffset);
    
    CGPoint vLeftUpPoint = CGPointMake(xOffset, yOffset + radius);
    CGPoint vRightDownPoint = CGPointMake(outerSize.width - xOffset, outerSize.height - yOffset - radius);
    
    CGPoint centerLeftUp = CGPointMake(xOffset + radius, yOffset + radius);
    CGPoint centerRightUp = CGPointMake(outerSize.width - xOffset - radius, yOffset + radius);
    CGPoint centerLeftDown = CGPointMake(xOffset + radius, outerSize.height - yOffset - radius);
    CGPoint centerRightDown = CGPointMake(outerSize.width - xOffset - radius, outerSize.height - yOffset - radius);
    
    [bezierPath moveToPoint:hLeftUpPoint];
    [bezierPath addLineToPoint:hRightUpPoint];
    [bezierPath addArcWithCenter:centerRightUp radius:radius startAngle:M_PI * 3 / 2 endAngle:M_PI * 2 clockwise:YES];
    
    [bezierPath addLineToPoint:vRightDownPoint];
    [bezierPath addArcWithCenter: centerRightDown radius: radius startAngle: 0  endAngle: M_PI / 2 clockwise: YES];
    [bezierPath addLineToPoint: hLeftDownPoint];
    [bezierPath addArcWithCenter:centerLeftDown radius: radius startAngle: M_PI / 2 endAngle: M_PI clockwise:YES];
    
    
    [bezierPath addLineToPoint:vLeftUpPoint];
    [bezierPath addArcWithCenter:centerLeftUp radius: radius startAngle: M_PI endAngle: M_PI * 3 / 2 clockwise: YES];
    [bezierPath addLineToPoint: hLeftUpPoint];
    [bezierPath closePath];
    
    //If draw drection of outer path is same with inner path, final result is just outer path.
    [bezierPath moveToPoint: CGPointZero];
    [bezierPath addLineToPoint:CGPointMake(0, outerSize.height)];
     [bezierPath addLineToPoint:CGPointMake(outerSize.width, outerSize.height)];
     [bezierPath addLineToPoint:CGPointMake(outerSize.width, 0)];
     [bezierPath addLineToPoint:CGPointZero];
    [bezierPath closePath];
    
    [fillColor setFill];
    [bezierPath fill];
    
    CGContextDrawPath(currentContext, kCGPathFillStroke);
    UIImage *antiRoundedCornerImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return antiRoundedCornerImage;
}