While something similar would probably be better, this is heavily optimized for pixel artwork. Lots of curves, shading, and most importantly - limited colors. UI is generally much straighter, less shaded, with far more colors.
Here's an example of UI that's scaled with potrace (a similar algorithm): http://i.imgur.com/jDq4M7e.png (left side is the converted side, right side is nearest-neighbor. Top is 3x, bottom is 2x)
That's with the highest amount of colors/depth that potrace allows. On an i7 processor, it takes a LONG time to compute all of that. Each icon is no longer just a couple hundred pixels, it's a couple hundred vector paths. Even rendering it takes a number of seconds to refresh the screen in inkscape.
I think the ideal would be something similar to fonts: there's the vector definition for big sizes, and optional pixel-perfect definition for small sizes, because rendering vectors on very small sizes (16x16, 32x32) might look worse than hand-crafted pixel work.
These days, font rendering does not often rely on bitmaps, even at small sizes. Instead, they typically use hinting and subpixel rendering. I would love to see these effective techniques applied to vector graphics too.
Linux has had vector icons on the desktop for over a decade now. It truly boggles my mind how Apple (especially once they realized Retina was coming) hasn't gone fully resolution-independent on the UI side by now…
Here's an example of UI that's scaled with potrace (a similar algorithm): http://i.imgur.com/jDq4M7e.png (left side is the converted side, right side is nearest-neighbor. Top is 3x, bottom is 2x)
That's with the highest amount of colors/depth that potrace allows. On an i7 processor, it takes a LONG time to compute all of that. Each icon is no longer just a couple hundred pixels, it's a couple hundred vector paths. Even rendering it takes a number of seconds to refresh the screen in inkscape.