How to convert cut-out shapes to optimized stacked shapes with minimum points?

Question

What I want

I want to transform a raster image into a vector image with minimum number of vertices. (Specifically, into a sticker for a messaging app, which is a gzipped lottie file, but that's irrelevant, I think.)

What I do

The best vectorization app I could find is Vector Magic. The results are great, however stacking of shapes on top of each other doesn't work (or I don't understand its options). It transforms the raster image on the left to the vector image on the right:

Shapes are touching each other. If there's a zig-zag line, it's present on both sides. 124 points in total, which is great compared to anything that Adobe Illustrator's built-in image tracing can produce. However, this can be optimized (shapes shifted to show the difference):

That's 72 points with no loss in quality. However, that's a lot of manual work.

What I need

Is there any way to do this sort of shape stacking automatically? I doubt I'm the first person to have this problem, but no matter what I search for, I find nothing.

Answer 1

You probably don't want to hear this, but auto tracing will never give you a result like that - especially not with an image like the example which has blurry edges. At best, you might be able to achieve some degree of stacking using software such as Adobe Illustrator or Inkscape which both have stacking settings that you can use when auto tracing.

To be honest with you, to get the result you want, I think it would be easier and quicker to simply redraw it manually using the Bézier/Pen tool in vector image editing software, where you can use the raster image as a guide to make the curves, rather than wasting your time trying to correct an auto trace.

An example made in a few minutes in Inkscape using the Bézier tool. The same is of course possible in Illustrator using the Pen tool.

Answer 2

Since you're satisfied with the traced shapes, perhaps you could figure out a way to keep the bitmap stacked as transparent layers before tracing then?

This way the shapes below the yellow "squiggle" won't be cut out by it, for example, since you would be tracing one layer at a time.

The online sketchpad.app keeps each brush stroke in its own layer, so perhaps that type of tool could be used. Or something that can generate color separation layers like Photoshop for example.

I don't see many other options, as pointed out already in the Billy's answer.