🚀 go-pugleaf

In article <64476@hydra.gatech.EDU> cc100aa@xray.gatech.edu (Ray Spalding)  
writes:
[...]
> 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)

Is this correct? DL says:

---CUT---
NXRectClip() intersects the current clipping path with the rectangle referred
to by its argument, aRect, to determine a new clipping path. 
NXRectClipList() takes an array of count number of rectangles and intersects
the current clipping path with each of them.  Thus, the new clipping path is
the graphic intersection of all the rectangles and the original clipping
    ^^^^^^^^^^^^^^^^^^^^
path.  Both functions work through the rectclip operator.  After computing
the new clipping path, the current path is reset to empty.
---CUT---

I believe the Concepts manual says that if rectCount == 2 then the two  
rectangles will be disjoint (e.g. due to a diagonal scroll). In this case  
then the above code would clip out everything and no redrawing would occur.  
Fortunately, this case usually only occurs under program control so this  
rarely happens.

A stumbled across this issue in the Draw source. In there, if there are 2  
rectangles, then the image is drawn twice, the first time clipped to the  
first rectangle and then again clipped to the other rectangle. You would  
either have to do that or set up a PostScript clipping path.

Dave

--
David K. Hess
Graduate Assistant                     David-Hess@tamu.edu
Supercomputer Center                  Texas A&M University