SVG Paths detect overlapping or enclosed shapes

Question

I have brown filled svg paths and i want to detect and alert my user if there is any shape behind or above another shape. I know intersection list gets if they intersect at the edges but what happens if i want to detect a shape that is behind another shape but doesnt intersect at the edges?

The encoluseList method seems to be dealing with bounding boxes and not this.

Any ideas?

Answer 1

To detect if a path/shape overlaps another
1. Calculating the area covered by the final shape achieved
2. Calculating the sum of areas of all the shapes independently(since this is SVG and the details of each path element is known, this can be done)
3. Comparing the 2 areas.If the 2 areas are the same, then there is no overlapping otherwise at least 2 shapes overlap.

The tricky step is step 1 which can be approximately calculated using pixel painting algorithm(my preference). For other methods, you can go through the following stackoverflow question concerning area of overlapping circles