1. I have confirmed that a geometric pen cannot be used to produce a vector output. As an experiment I modified the Python code above to use the call to ExtCreatePen to create a geometric pen. With a geometric pen it was not possible to produce a "Vector" output. Even at a linewidth of zero pixels, an ordinary (geometric) line was both outlined and also filled with an apparent linewidth of 1 pixel. Neither of these are acceptable, so I am going to abandon this line of enquiry which was to modify Inkscape code to do this, and concentrate instead on the Python approach.
2. A partially positive test of the Python code has been reported at Bug 966244. If I can respond to the remaining outstanding issue mentioned there, then I will post a new version there.
two quick comments:
1. I have confirmed that a geometric pen cannot be used to produce a vector output. As an experiment I modified the Python code above to use the call to ExtCreatePen to create a geometric pen. With a geometric pen it was not possible to produce a "Vector" output. Even at a linewidth of zero pixels, an ordinary (geometric) line was both outlined and also filled with an apparent linewidth of 1 pixel. Neither of these are acceptable, so I am going to abandon this line of enquiry which was to modify Inkscape code to do this, and concentrate instead on the Python approach.
2. A partially positive test of the Python code has been reported at Bug 966244. If I can respond to the remaining outstanding issue mentioned there, then I will post a new version there.