如何找出屏幕上实际可见的显示视图内容的矩形 (CGRect).
How can I go about finding out the rect (CGRect) of the content of a displayed view that is actually visible on screen.
myScrollView.bounds
上面的代码在没有缩放时有效,但是一旦你允许缩放,它会在缩放比例不是 1 时中断.
The code above works when there's no zooming, but as soon as you allow zooming, it breaks at zoom scales other than 1.
为了澄清,我想要一个包含滚动视图内容的可见区域的 CGRect,相对于内容.(即,如果它是缩放比例 2,矩形的大小将是滚动视图大小的一半,如果它是缩放比例 0.5,它将是两倍.)
To clarify, I want a CGRect that contains the visible area of the scroll view's content, relative to the content. (ie. if it's a zoom scale 2, the rect's size will be half of the scroll view's size, if it's at zoom scale 0.5, it'll be double.)
回答我自己的问题,主要感谢 Jim Dovey 的回答,这并没有完全解决问题,但给了我回答的基础:
Answering my own question, mostly thanks to Jim Dovey's answer, which didn't quite do the trick, but gave me the base for my answer:
CGRect visibleRect;
visibleRect.origin = scrollView.contentOffset;
visibleRect.size = scrollView.bounds.size;
float theScale = 1.0 / scale;
visibleRect.origin.x *= theScale;
visibleRect.origin.y *= theScale;
visibleRect.size.width *= theScale;
visibleRect.size.height *= theScale;
主要区别在于 visibleRect 的大小应该是 scrollView.bounds.size
,而不是 scrollView.contentSize
是内容视图的大小.还稍微简化了数学,并没有完全看到 isless()
的用途,它会在代码更大时破坏代码.
The main difference is that the size of the visibleRect ought to be scrollView.bounds.size
, rather than scrollView.contentSize
which is the size of the content view. Also simplified the math a bit, and didn't quite see the use for the isless()
which would break the code whenever it's greater.
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