[MACTCL] XMoveResizeWindow, TkMacOSXInvalClipRgns, and TkMacOSXUpdateClipRegions

[james t. <ti...@ma...>]

ok,

...well, finally been up and running for the last week, so I just  
wanted to do some thinking out loud, and perhaps some group think  
will help...

...when we last talked about this in december, I had tracked down  
some "aggressive" re-drawing that Tk is doing in a particular example  
patch provided by mads linden:  basically, when XMoveResizeWindow is  
called, it's invalidating everything that's a child subwindow, which  
is forcing an update of the all of the child subwindow clipping  
regions when the window is next drawn...

...a better way to do this would be to limit the area that is  
invalidated, or update just the clipping area that is being affected,  
and not the entire window and it's subwindows...that seems simple to  
say, but I'm a bit confused as to how to do this, based on how the  
code is now...for instance, should there be another function similar  
to TkMacOSXInvalClipRgns that somehow figures out just the area that  
needs to be invalidated, and then invalidates just those subwindows?   
Is this even possible given Tk's drawing model (ie. do we have that  
kind of information at hand when the decision is to be made)?

...also, I don't understand why this particular event is spawning  
calls to XMoveResizeWindow and not XMoveWindow, since there isn't any  
resizing of any of the windows involved?  I realize that these  
functions are basically copies of each other code-wise, so it may be  
a no-issue...OTOH, in both there is a note that says "It is currently  
assumed that Tk will need to completely redraw anyway", so it seems  
likely this is a place to attack...?

...finally, I had shown jeff an "n-squared" problem with this  
invalidation/updating, but I've since found that that only occurs  
during the set-up/mapping of the windows:  actual redrawing doesn't  
seem to be done "n-squared", but it is done for everything whether it  
was affect by the move or not...

...so I'm all over the place, and feedback is greatly appreciated!
jamie