让UIView斜缩小

[UIView animateWithDuration:0.5 animations:^{
        CGAffineTransform t = CGAffineTransformMakeRotation(M_PI * .3);
        t = CGAffineTransformScale(t, .75, .75);
        _moveView.transform = t;
    } completion:^(BOOL finished) {
        [self drop];
}];