W3C home > Mailing lists > Public > www-svg@w3.org > July 2008

SVG 1.1 F.6 Elliptical Arc Implementation Notes

From: Dr. Olaf Hoffmann <Dr.O.Hoffmann@gmx.de>
Date: Sat, 12 Jul 2008 17:38:23 +0200
To: www-svg@w3.org
Message-Id: <200807121738.23626.Dr.O.Hoffmann@gmx.de>

Hello SVG WG ;o)


Due to the previous discussion about the elliptical arc commands missing
in tiny profiles 

http://lists.w3.org/Archives/Public/www-svg/2008Jun/0055.html
http://lists.w3.org/Archives/Public/www-svg/2008Jun/0056.html
http://lists.w3.org/Archives/Public/www-svg/2008Jun/0058.html
http://lists.w3.org/Archives/Public/www-svg/2008Jun/0059.html

I created some PHP scripts to approximate elliptical arc commands and 
some other parametrisations of ellipses with cubic curves, currently 
available here:
http://hoffmann.bplaced.net/hilfe.php?me=svg&in=svgkurven#ellip


For these scripts I 'implemented' SVG 1.1 F.6 'Elliptical arc implementation
notes' into the PHP scripts and found some minor inconsistencies/typos in
these notes:



1. The PNG with something looking like the greek letter phi with the name
psi.png has the alternative text (img alt attribute) psi.
This might confuse a discussion about this section between people beeing able
to identify greek letters from the graphical repesentation and other people, 
who identify them by the given alternative text.
Either the PNG schould be modified to show a greek psi or the image name and
alternative text should be changed to phi(.png).



2. in F.6.3 the last paragraph including three PNGs, the second image shows 
theta1, obviously this should bei theta2



3. in F.6.5 it is asserted, that the task is to find
cx, cy, rx, ry, psi, theta1, delta theta and given is x1, y1, x2, y2, fA, fs.

Following this section and the notation of the elliptical arc command, psi is 
given too and is not to be found.
Received on Saturday, 12 July 2008 15:41:12 GMT

This archive was generated by hypermail 2.3.1 : Friday, 8 March 2013 15:54:39 GMT