Re: scrolling an NSImageView leaves tracks

FROM : Vince DeMarco
DATE : Mon Apr 11 16:00:16 2005

On Apr 9, 2005, at 12:53 PM, Geoff Levner wrote:

> I have an NSImageView in an NSScrollView. I can zoom in and out, 
> scroll, load new images, and everything is fine.
>
> Except for one thing. Sometimes, when a newly loaded image is 
> initially framed so that it is clipped by the scroll view, 
> scrolling leaves tracks (grey vertical or horizontal lines) where 
> previously clipped portions of the image become visible.  Zooming 
> in or out once makes them go away.  Calling the NSClipView's 
> setCopiesOnScroll method with NO also makes the problem go away, 
> but then, of course, scrolling is much slower.
>
> Has anybody out there ever encountered this sort of behavior?
>


This happens when the coordinates of either the scrollview or the 
contents of the scroll view are on non integral boundaries.

Get the frame of the views, and print then out to check this.

The fix is to use NSIntegralRect() on the frame before setting it.

vince

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