CGRectOffset

CGRectOffset(frame,dx,dy)

实例

UIView *redV = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 100, 100)];

    redV.backgroundColor = [UIColor redColor];

    [self.view addSubview:redV];

    

    CGRect rect2 = CGRectOffset(redV.frame, -20, 20);

    

    UIView *grrenView = [[UIView alloc]initWithFrame:rect2];

    grrenView.backgroundColor = [[UIColor greenColor]colorWithAlphaComponent:0.5];

    [self.view addSubview:grrenView];

 

//运行结果   dx或者 dy为负数的时候左移 或者上移，dx或者dy为正数的时候右移或者或者下移