Tensor product patch fill documentation bug

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#1017

From: Palasik Sandor
Date: Fri, 30 May 2003 07:59

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Hi!

I think, the formula, that relates Coons patches to Tensor Product patches
in the Postscript level 3 and PDF 1.4 reference manuals is simply not true.

On page 286 of the PLRM and page 259 of the PDF 1.4 RM:

p11 = S(1/3,2/3)
p12 = S(2/3,2/3)
p21 = S(1/3,1/3)
p22 = S(2/3,1/3)

Were S is the Coons surface equation:

S = Sc + Sd - Sb

I think in general the internal control points of a Bezier type surface
cannot be on the surface itself, and also, if I generate Type 7 shadings
from Type 6 shadings with the above mentioned formulas, the results look
different.

Have anyone stumbled on this before?

Palasik Sandor

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From: "Palasik Sandor" <palasik@vipmail.hu>
Newsgroups: adobe.postscript.programming
Subject: Tensor product patch fill documentation bug
Date: Fri, 30 May 2003 09:59:34 +0200
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