可以UIScrollView zoomToRect？

Question

有没有办法确定一个UIScrollView是否可以在maximumZoomScale和minimumZoomScale内zoomToRect:？如果所需的zoomScale太小，请返回NO。

Answer 1

也许这种事情可能奏效？ （想法从https://stackoverflow.com/a/2125472/845115略被盗）

- (BOOL)scrollView:(UIScrollView*)scrollView canZoomToRect:(CGRect)zoomToRect { 
    CGPoint contentOffsetBefore = scrollView.contentOffset; 
    CGFloat zoomBefore = scrollView.zoomScale; 
    [scrollView zoomToRect:zoomToRect animated:NO]; 
    CGFloat zoomAfter = scrollView.zoomScale; 

    [scrollView setZoomScale:zoomBefore animated:NO]; 
    [scrollView setContentOffset:contentOffsetBefore animated:NO]; 

    return (zoomBefore == zoomAfter); 
}