对于图片的拉伸

- (void)insetsMake

{

    UIImageView * thermometer = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 100, 100)];

    UIImage* image = [UIImage imageNamed:@"Thermometer.png"];

    UIEdgeInsets insets = UIEdgeInsetsMake(20, 0, 25, 0);

    image = [image resizableImageWithCapInsets:insets];

    [thermometer setImage:image];

}

//UIEdgeInsetsMake(20, 0, 25, 0);（top,left,bottom,right)设置的为上、左、下、右的距离，只有在这个范围内的区域才可以进行拉伸