Thanks for your information. I think the support generation you've mentioned is https://github.com/Ultimaker/CuraEngine/pull/655 I'll probably change the thick trunk to thin tubes for SLA. Anyway it should make my job a lot easier.
Moreover, regarding the sliced preview in Cura, where the gcode path has been shown in different color, I guess it's done by Cura interpreting the gcode generated by CuraEngine. If so, should that part of Cura be changed to show raster images?