Question

http://childhoodgamedev.qiniudn.com/xincheng_testGif.gif

UILabel* label = [[UILabel alloc] initWithFrame:CGRectMake(250, 250, 200, 100)];
label.text = @"Hello world!";
label.textColor = [UIColor blackColor];
label.textAlignment = NSTextAlignmentLeft;
label.backgroundColor = [UIColor clearColor];
label.font = [UIFont systemFontOfSize:25];
[self.view addSubview:label];

CGAffineTransform transform = CGAffineTransformIdentity;
label.transform = CGAffineTransformScale(transform, 2, 2);

[UIView animateWithDuration:4.0 delay:0 options:UIViewAnimationOptionCurveLinear animations:^{
    label.transform = CGAffineTransformTranslate(label.transform, -100, 0);
} completion:^(BOOL finished) {
    if (finished) {
        NSLog(@"label %f %f %f %f", label.frame.origin.x, label.frame.origin.y, label.frame.size.width, label.frame.size.height);
        [UIView animateWithDuration:3.0 delay:0 options:UIViewAnimationOptionCurveLinear animations:^{
            NSLog(@"label %f %f %f %f", label.frame.origin.x, label.frame.origin.y, label.frame.size.width, label.frame.size.height);

            label.transform = CGAffineTransformTranslate(label.transform, 100, 0);
        } completion:NULL];
    }
}];

UILabel个实例名为label，它按CGAffineTransformScale缩放为2比率。然后它从右向左移动，当动画完成时，它从左向右移动。

但奇怪的是：它看起来不是同一个位置，这是动画的终点（从右到左），动画的起点（从左到右）。但NSLog告诉我，他们处于相同的位置。

http://childhoodgamedev.qiniudn.com/xincheng_QQ20150306-1.png

当我评论州label.transform = CGAffineTransformScale(transform, 2, 2);时，一切都很好。当标签改变方向移动时，右 - >左动画的结束位置只是左 - 右动画的起始位置。

所以我认为问题是由CGAffineTransformScale引起的。有什么想法吗？

UIView动画和变换导致奇怪的位置偏移

0 个答案: