uiimage拉伸

-(IBAction)stretchImageView

{

    UIImage *image1 =[UIImage imageNamed:@"direction.png"];

    image1=[image1 stretchableImageWithLeftCapWidth:image1.size.width*0.5 topCapHeight:image1.size.height*0.5];

    [self.directionImageView setImage:image1];
}