Re: Scrolling Behavior of NSTextView
Re: Scrolling Behavior of NSTextView
- Subject: Re: Scrolling Behavior of NSTextView
- From: Dong Feng <email@hidden>
- Date: Tue, 8 Jun 2010 07:56:18 +0800
Thanks for all your replies, Martin and Paul.
Martin, I tried the " [NSTextView scrollRangeToVisible:] with
NSMakeRange(0,0) ", but it is the same as to use [scrollPoint:] solely. Only
with [glyphRangeForTextContainer:] in prior the scroll-to-top works. I don't
think it is the problem of coordinate system flip-ness, because when using
[scrollPoint:] without [glyphRangeForTextContainer:], the text view does not
always scroll to bottom, either, it just does not always scroll to top under
certain window size and text length. And it seems not solely
[glyphRangeForTextContainer:] triggers the scroll-to-top because without
[scrollPoint:] the scrolling does not work, either.
Another minor wired problem is the trick of using both
[glyphRangeForTextContainer:] and [scrollPoint:] works only when you
drag-drop a NSScrollView in IB and then set the embedded custom view as
NSTextView. If an NSTextView is dragged and dropped directly (and IB
automatically embed it in a NSScrollView), the scroll-to-top does not work
even with the trick (and I haven't found a trick to make it work under such
situation).
Regards,
Dong
在 2010年6月8日 上午5:29，Martin Wierschin <email@hidden>写道：
> On 2010.06.07, at 2:10 PM, Paul Sanders wrote:
>
> I haven't looked at your code so I don't know what is going on in detail
>> but [NSLayoutManager glyphRangeForTextContainer:] performs layout, if it
>> hasn't been done already, which is probably why it is affecting the results
>> you get. Until layout has been performed, the Cocoa text system doesn't
>> know the size of the text (in terms of the amount of space it will take up
>> on the display) and so (I surmise) scrollPoint: doesn't work as expected.
>>
>
> You're right about triggering layout, but there's no reason the text system
> should have any trouble with NSMakePoint(0,0). NSTextView and the Cocoa
> layout system always use a flipped coordinate system, so the origin is
> always top-left.
>
> Perhaps the problem is that once layout completes (or during layout), you
> (or Cocoa) is automatically scrolling the text view somewhere else? I'd
> break in the debugger to see if anything else is triggering unwanted
> scrolling.
>
> ~Martin
>
>
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