align stroke to path

Summary:

Align stroke to the path is a feature that is missing from Inkscape. Historically we did not add it coz SVG did not support it. But we also have LPE that are not SVG supported and we flatten them for SVG export. I suggest we do the same for this feature

implmentation idea

• we would add 3 icons in to stroke style dialog:center ,inside outside
• underhood (not seen LPE interface) we would add modified LPE offset : with offset calculation:

inside: stroke size*0.5

outside: stroke size*-0.5

• we would keep it underactive but on SVG export we would flatten this LPE (same as for many other LPES)