I've been looking into this change and there is a slight problem:)
EndPaint (windows function) needs to have passed a structure that contains the same painting information that was retrieved from BeginPaint (windows function). Somehow this information needs to be stored  between the calls.
In the Perl world, you would do something like:
#do painting here
Which means that the pointer returned from BeginPaint (or the contents of the pointer) need to be stored somewhere. The current approach is to create a hash and associate it with the window. The ideal way would be to associate the pointer to the window - not the data.
Or perhaps an alternative approach might be more suitable? Something like:
$win->BeginPaint( \&Paint);
sub Paint {
  my ($DC,$x,$y,$x1,$y1)=@_;
  #do painting
Where BeginPaint, is passed a reference to a sub, BeginPaint then calls windows BeginPaint,  the sub ref is called, passed all the parameters, then finally calls EndPaint?  But, then why not define the Paint event directly (ie, -onPaint)?
----- Original Message -----
From: Jez White
To: guihackers
Sent: Friday, May 14, 2004 3:22 PM
Subject: [perl-win32-gui-hackers] GUI.xs (BeginPaint and EndPaint)

Would any one have any objections if I change (fix depending on your viewpoint:) ) the BeginPaint and EndPaint functions in GUI.xs?
I think these functions are left over from previous versions (along with the other painting/drawing functions in GUI.xs). They are currently not used by any other internal functions, nor are they documented anywhere. The general usage would stay the same, but I plan to return the details as an array (dc,x,y,x1,x2,flag) rather than messing with the object itself. I think this would be cleaner, faster and more like other xs functions.
In general usage these functions would be used in conjunction with a Hooked WS_PAINT message, allowing the users program to handle the painting of window directly. A good example, would be the bitmap scrolling example ask for by Glenn Linderman, instead of painting the bitmap into a image control, it could be painted direct into the windows DC (I'll try and put together an example this weekend).