🚀 go-pugleaf

In article <151l40INNn1m@agate.berkeley.edu> william@moica.berkeley.edu (William E. Grosso) writes:
>I have a strange prboblem with a ScrollView. It seems to 
>lose branches of the view hierarchy when scrolling 
>(e.g. a subview and all it's descendants will occasionally
>just diappear). Sometimes they reappear if I continue scrolling.
>
>Has this happened to anybody else before ? Any clues as to what
>is going wrong ?

Yes, this has happened to me.

When you scroll in a piece of a view, drawSelf:: normally is sent
only to the subviews that intersect the newly exposed portion.  If
you have overlapping views, like some shapes (each in a subview)
on a larger background subview, your background will sometimes get
drawSelf:: whereas not necessarily all your shapes will.  The drawing
of the background may then overlay some or all of the shapes.

One way to fix this is to set the proper clipping path before
displaying your background view.  Something like:

- drawSelf:(const NXRect *)rects :(int)rectCount
{
        if (rectCount == 1) NXRectClip(rects);
        else NXRectClipList(rects+1,2);

-- 
Ray Spalding, Office of Information Technology
Georgia Institute of Technology, Atlanta Georgia, 30332-0715
Internet: ray.spalding@oit.gatech.edu (NeXT Mail accepted)