Object in Comos can be color filled. It was not implemented in the previous engine. creating a filled path in comos creates a few additional lines in the CRP file compared to writing a normal line. The first step involve defining the path itself, the next step is assigning a line to a variable while the final one involve adding the line variable to the path itself.
The code is written in such a way that the fill path is only drawn only after the current object is fully drawn. The reason for this is because there is no way on telling weather the last line has been added to the path. I dont think this code will play nice with arc element.
Aside from the arc problem there is also the fact that in order for path fill to work in svg the path need to be continuos so for a triangle the line must be defined in such that point a to b, b to c and c to a. THe problem with crp is that isted of points the defined item are line so the three elements defiend wil be line ab, bc, ca. The code will only work if the line element is arrenged in such a manner, but it will get messed up if the element are defined differently ab, ca, bc or even ab cb ca. damnn. I can think of a solution but maybe later.