Hi again,
After some procrastination, I have found time to fix some issues with the arc editor feature I proposed a while ago. (See here: https://sourceforge.net/p/inkscape/mailman/message/31695400/)
I have uploaded my latest changes to launchpad. https://code.launchpad.net/~danieljabailey/inkscape/arc_node_editor
The new changes allow you to convert an arc to a bezier curve (simply by using the "make selected segments curve" button). I have also fixed the bug that was pointed out to me, which meant that an arc at the end of a path would sometimes become a straight line.
I am facing one more issue however, when converting an arc to a bezier, some arcs cause a segfault. The easiest way to reproduce this is to convert a circle to a path and then try to convert the resulting arcs to beziers. (Arc to bezier conversion being the feature I recently added.)
I seem to get the segfault on a line that sets the position of a bezier handle. This is in a function I have added, "PathManipulator::replaceSegmentWithPath". Sometimes this works and sometimes it doesn't. Valgrind and gdb have, surprisingly, not been particularly helpful.
Any advice would be much appreciated, I'm not sure if I am re-implementing things that already exist by adding the replaceSegmentWithPath function. Perhaps there is already some code for this which I can use.
Thanks, Dan.