Path: utzoo!utgpu!water!watmath!clyde!rutgers!rochester!bbn!uwmcsd1!ig!agate!ucbvax!ucsfcgl!cgl.ucsf.edu!conrad
From: conrad@cgl.ucsf.edu (Conrad Huang%CGL)
Newsgroups: comp.windows.news
Subject: Non-transparent canvas problem?
Message-ID: <10676@cgl.ucsf.EDU>
Date: 4 Feb 88 01:48:17 GMT
Sender: daemon@cgl.ucsf.edu
Reply-To: conrad@socrates.ucsf.edu (Conrad Huang)
Organization: UCSF Computer Graphics Lab
Lines: 26

I've been trying to implement a double-buffered window on top of
LiteWindow and have run into a problem.  My current approach is,
in essence, to use two ClientCanvas's and swap them without telling
LiteWindow about it (by overriding some of the inherited methods).
By default, ClientCanvas is a transparent canvas, and I really want
non-transparent canvases for double buffering.  So, I said to myself,
this ought to be easy.  We just wrap our own method around
CreateClientCanvas and make the ClientCanvas non-transparent.  HA!
After hours of fiddling and server core dumps, I gave in and just
copied the LiteWindow code, renamed it MyWindow, and inserted the line

	/Transparent false def

immediately after

	/Mapped true def

in the CreateClientCanvas method.  I loaded the file, created a window,
sent it a /reshapefromuser message, and the server core dumped.  Is this
a known bug?  Is it fixed in 1.1?  Has anyone implemented double-buffered
windows?  Help!

Conrad

PS	This work was done on NeWS 1.0.  We ordered 1.1 but haven't gotten
it yet.