From: Dr. Olaf Hoffmann <Dr.O.Hoffmann@gmx.de>

Date: Sat, 4 Sep 2010 13:22:16 +0200

To: www-svg@w3.org

Message-Id: <201009041322.16680.Dr.O.Hoffmann@gmx.de>

Date: Sat, 4 Sep 2010 13:22:16 +0200

To: www-svg@w3.org

Message-Id: <201009041322.16680.Dr.O.Hoffmann@gmx.de>

Dirk Schulze: >... >Can the specification provide a more detailed algorithm how to >flatten/normalize a path, and how to synchronize both types of segment >lists? Conversion from relative paths to absolute paths and S to C and T to Q and H, V to L as mentioned in SVG tiny 1.2 should be trivial. Within my SVG+PHP tutorial I looked on similar issues to normalise even more path data - typically useful to animate from one shape to another. It is for example possible to provide exact conversion rules from affine and quadratic curves to cubic curves. However, because there is an infinite number of possible parametrisations, the result depends on these parametrisations, what matters for example within animation, if the converted paths are animated and not the paths converted for every interpolation step. To calculate the animation result and convert it then for the rendering each time of course avoids problems with the parametrisation dependence. If elliptical arcs are approximated with cubic curves, one always has to do the approximation for each animation interpolation step. And because it is an approximation, to provide a simple rule to get the cubic curves path segments representing an elliptical arc within the requirement of SVG to have at least an accuracy of one device pixel might be not trivial. For this to hear some ideas how to get it correct enough and fast (with a minimal number of cubic curves to meet the required precision) at the same time would be interesting :o) OlafReceived on Saturday, 4 September 2010 11:44:33 UTC

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