From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.comp.tex.context/17903 Path: main.gmane.org!not-for-mail From: Mojca Miklavec Newsgroups: gmane.comp.tex.context Subject: Re: shading in meta[post/play] & PDF Date: Fri, 21 Jan 2005 00:47:37 +0100 Message-ID: <41F04319.2070402@guest.arnes.si> References: <20050115210457.24F53127CC@ronja.ntg.nl> <41EE2FA8.4080002@guest.arnes.si> <41EE4903.4060705@wxs.nl> Reply-To: mailing list for ConTeXt users NNTP-Posting-Host: deer.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Trace: sea.gmane.org 1106264977 20060 80.91.229.6 (20 Jan 2005 23:49:37 GMT) X-Complaints-To: usenet@sea.gmane.org NNTP-Posting-Date: Thu, 20 Jan 2005 23:49:37 +0000 (UTC) Original-X-From: ntg-context-bounces@ntg.nl Fri Jan 21 00:49:19 2005 Return-path: Original-Received: from ronja.vet.uu.nl ([131.211.172.88] helo=ronja.ntg.nl) by deer.gmane.org with esmtp (Exim 3.35 #1 (Debian)) id 1Crm3D-0002Iq-00 for ; Fri, 21 Jan 2005 00:49:19 +0100 Original-Received: from localhost (localhost.localdomain [127.0.0.1]) by ronja.ntg.nl (Postfix) with ESMTP id EE99E1279C; Fri, 21 Jan 2005 00:49:17 +0100 (CET) Original-Received: from ronja.ntg.nl ([127.0.0.1]) by localhost (ronja.vet.uu.nl [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 04144-06; Fri, 21 Jan 2005 00:49:15 +0100 (CET) Original-Received: from ronja.vet.uu.nl (localhost.localdomain [127.0.0.1]) by ronja.ntg.nl (Postfix) with ESMTP id 7EC791277C; Fri, 21 Jan 2005 00:49:15 +0100 (CET) Original-Received: from localhost (localhost.localdomain [127.0.0.1]) by ronja.ntg.nl (Postfix) with ESMTP id EBF7B1277C for ; Fri, 21 Jan 2005 00:49:14 +0100 (CET) Original-Received: from ronja.ntg.nl ([127.0.0.1]) by localhost (ronja.vet.uu.nl [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 04311-01 for ; Fri, 21 Jan 2005 00:49:13 +0100 (CET) Original-Received: from acheron.informatik.uni-muenchen.de (unknown [129.187.214.135]) by ronja.ntg.nl (Postfix) with ESMTP id 92F911277B for ; Fri, 21 Jan 2005 00:49:13 +0100 (CET) Original-Received: from internaldeliver.acheron.informatik.uni-muenchen.de (localhost [127.0.0.1]) by acheron.informatik.uni-muenchen.de (Postfix) with ESMTP id 032CB43614 for ; Fri, 21 Jan 2005 00:47:46 +0100 (CET) Original-Received: from [141.84.28.148] (a148.lmu.vpn.lrz-muenchen.de [141.84.28.148]) (using TLSv1 with cipher RC4-MD5 (128/128 bits)) (No client certificate requested) by acheron.informatik.uni-muenchen.de (Postfix) with ESMTP id D1016435CB for ; Fri, 21 Jan 2005 00:47:45 +0100 (CET) User-Agent: Mozilla/4.5-4.75 (Windows; U; Windows NT 5.1; sl-SI; rv:1.4) Gecko/20030624 Netscape/7.1 X-Accept-Language: sl, en, en-us, de Original-To: mailing list for ConTeXt users In-Reply-To: <41EE4903.4060705@wxs.nl> X-Virus-Scanned: by amavisd-new at ntg.nl X-BeenThere: ntg-context@ntg.nl X-Mailman-Version: 2.1.5 Precedence: list List-Id: mailing list for ConTeXt users List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: ntg-context-bounces@ntg.nl Errors-To: ntg-context-bounces@ntg.nl X-Virus-Scanned: by amavisd-new at ntg.nl Xref: main.gmane.org gmane.comp.tex.context:17903 X-Report-Spam: http://spam.gmane.org/gmane.comp.tex.context:17903 Hans Hagen wrote: > Mojca Miklavec wrote: > >> How can I make shading inside metapost(play) to produce exactly what's >> in the attached picture (smooth shades). Or more generally: how can I >> "hardcode" some PS/PDF code in .mp, not (yet) supported by >> metapost(play)? > > > certain kind of native level 2 shaded can be done with the metafun > macros (circular and linear vector based) > > a couple of years ago mathew baker and i played with more advanced > features using functions and such but i need to locate that code; > > if you're willing to figure out what (in pdf) functionality is needed i > can extend the current metapost shading handler with a few more > alternatives [the function based ones, since that's what you're looking > for]) I'm not sure if I understood the question correctly (about what should I figure out). I would like to draw a sphere (possibly with different colors on different points of the sphere; which would then be interpolated across the whole surface). Problem description: I have a computer program, which carries the data about the grid points on a sphere (possibly with different colors defined in these points) and how the points are connected with each other to form a grid. I would take these triangles (or quadrilaterals), draw them transformed on the plane (with curves, not with straight lines) and fill them with the appropriate shading pattern (colors defined in corners of the triangles (darker according to normal vector) simply interpolated between the three points). Yet another possibility would probably be to use function-based shading and define a function which knows how the points have to be shaded on the sphere, but the latter seems more complicated and less universal. Problem reduction: Fill a mp closed path with any more complex shading. So I would probably need Type 6 or 7 shading (Type 4 would be OK as the picture can be clipped within metapost, so that the resulting sphere borders are not composed of straight lines; the articles on http://www.math.ubc.ca/people/faculty/cass/graphics/text/www/ which inspired me to do something so crazy actually use Type 4 shading). Type one is probably the most general one, so it should be OK too, just complicated to do. However: I'm not sure if, say, a (sampled) function to be passed to PDF can be specified in metapost elegantly. Page 746 of PDF Reference, version 1.6 also defines an interesting new feature: 3D objects (3D Artwork as they call it), but I haven't found anything else about that. In dvipdfm there's an example of using: \special{pdf: bt rotate 90 xscale 2.0 } These lines are to be used in TeX. MetaPost also knows a "special" command, I just don't know how to use it. (This is probably the "communication channel" to PDF when trying to implement some more exotic shadings.) I glimpsed the mp-spec.mp file, but I didn't yet understand how the parameters are passed to PDF. > [more a context mailing list issue than a metapost list issue] So I left the metapost group out. Actually, 90% on the people here probably think I posted that to the wrong group anyway (in the sense of "Are you sure you didn't want to post that question to the 3D studio max mailing list?" :) The example above is probably not the most descriptive one, but having the possibility to add some more advanced shading patterns would be great. Thank you, Mojca