Merge shapes and draw border around final shape

I can't post images yet: http://i.imgur.com/7Kci5.jpg

Using Actionscript 3 I'm drawing multiple Shapes onto a MovieClip [top drawing]. The end result I need is the bottom drawing. I or开发者_运维问答iginally thought it would be simple to just merge the shapes and then find a way to draw a border around the end result but I can't seem to find any way of doing this.

Is this possible or is there a better way of trying to do this?

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there are 3 ways to go:

1. hard math. don't draw them directly, but draw through an additional abstraction layer where calculate the resulting curves and draw them.
2. simple abstraction layer. instead of drawing directly, draw them twice in 2 colors, an inner and an outer one, the outer being one pixel bigger (obvious in the case of circles at least). Only works if you draw into the same Graphics object.
3. use a GlowFilter with no blur (try what using 1 does) and knockout set to true.

greetz
back2dos