Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!rutgers!ucla-cs!zen!ucbvax!ZERMATT.LCS.MIT.EDU!RWS From: RWS@ZERMATT.LCS.MIT.EDU (Robert Scheifler) Newsgroups: comp.windows.x Subject: Xv11, PolyArc Message-ID: <870814080502.2.RWS@KILLINGTON.LCS.MIT.EDU> Date: Fri, 14-Aug-87 08:05:00 EDT Article-I.D.: KILLINGT.870814080502.2.RWS Posted: Fri Aug 14 08:05:00 1987 Date-Received: Sat, 15-Aug-87 18:21:15 EDT References: <2764881537-775490@Sierra> Sender: daemon@ucbvax.BERKELEY.EDU Distribution: world Organization: The ARPA Internet Lines: 26 Date: Thu, 13 Aug 87 17:38:57 CDT From: Kerry Kimbrough I recall that ANSI X3H33 developed for the CGI standard a clever parameterization that allowed the specification of "non-parallel" ellipses. Yes. Regrettably I also don't have my CGI leaf-press handy, but my recollection is that non-aligned ellipses are not required of a CGI implementation, there is an inquiry function to see if it is supported (of course, that's true of just about everything in CGI). Also, my recollection is that the algorithm is not published as part of CGI, and is actually owned and patented or copyrighted by some commercial company. Was this parameterization considered for Xv11? Was there a decision not to support "non-parallel" ellipses? Yes, and Yes. Depending on which camp you talk to, you will find two different opinions. One is that the "right" way to handle this and many similar things is to introduce an extension for general 2D coordinate transformation matrices in graphics contexts. This gives you local coordinates, scaling, and rotation in general (for lines, arcs, fonts, images, etc.). Along the way this can handle non-1:1 aspect ratios, and also supports a transition to non-bitmap scalable fonts. The other camp says "do PostScript as an extension". Some people sit in both camps. I rather expect that both will happen, eventually.