Mira Grudzinska

@JSUYA thanks for the rev please take a look on #992 as an introduction to this commit (I'll change this one accordingly)

@JSUYA @hermet please notice the comment that I made in the code: "Although svg viewers (like w3school) display different results than ThorVG, no justification for this behaviour was found in...

@hermet could you please be a bit more specific? all of the changes are already made in the sw_engine

I think that the def value is '"xMinYMin meet"'. Either way it should be changed

@hermet I took me some time to respond :D The issue is not solved, I try to solve it in the next week

solved in #1249

1) ```clipPathUnits``` added in #985 and #992 2) ```clip-path="circle() fill-box"``` format is not supported in tvg for now

@hermet the problem is, that tvg doesn't support filters. it seams that in the case, when some node has a filter, but the filter doesn't exist (like an invalid url)...

 and a small example code: ``` ``` nothing is plotted in w3school. tvg plots a red rect

do you think that we should turn off (for now) nodes with filters?