Hey guys.

This may sound like a bizarre request, but it would help me greatly in my little experiment. :)

Could you guys create 2x and/or 3x scaled versions of this image, without adding any new color?



Please, try to preserve the perceptual curvatures and line thickness as much as you can.
I want to study everyone's techniques used for this kind of thing.

I'm working on a pixel art scaling algorithm, and I just need a few goal posts.

All the existing ones are quite naive, I'm trying something different.
I already have a rough draft of one, but it still has its quirks.

Well, thanks in advance!

Edited by 1ucas - 16 March 2010 at 9:12pm

It is tougher than it looks, and it is even tougher for a computer to do it automatically.

That's why I'm trying to study just how we do it, so I can extract some useful information for the algorithm.

For example, you can't just duplicate the curves in size and add new pixels. You have to remove a few so the curvature looks right again, and the removal is uneven
depending on which side of the curve you're dealing with.

Here's an example:

(green pixels were added, red ones were removed)

Deciding which pixels to add and remove has been challenging, and getting a few examples would help me find the ideal technique.

Edited by 1ucas - 16 March 2010 at 8:24pm

I'm talking about adding and removing extra pixels after you do that, so the image looks larger but still smooth.

For example:


You start small, double the image, and fill in extra pixels between the doubled ones so the line looks sharp again.

It's a form of interpolation, but a more pixel art specific one.

more challenging than i thought at first, indeed.... heres my try on a 2x scaled version


(green - added/ red - removed)

tried to keep curvatures and thickness as good as i could.... the curves could be done better but i tried to keep a certain regularity in my process....
i somewhat feeled there was pattern to what i did, but im not rly able to explain it :(



Edited by onek - 18 March 2010 at 9:49am

ur welcome... im glad helping u ...i hope ull be successful with that algorithm.... though, i think it might be very difficult especially when it comes to multicolor stuff, like where is to be decided which colors gotta be kept and which removed etc.....
anyway i hope it will work out , since i also dont like that 2xsal/ hqnx etc. stuff very much...

Have you examined some of the existing pixel art scaling algorithms?

Oops! My bad. I quickly scanned this while at work and replied without reading fully. Apologies!

Anyhow, I wasn't suggesting that you should use them and not bother writing your own, but that they might be useful starting points for writing a new algorithm. I agree that they're fairly unsatisfying for a lot of things.

But you already knew about them, obviously, so my post was spectacularly pointless. I shall make amends by attempting to scale your image as requested.

EDIT: And here it is.



I found that when trying to precisely preserve line weight, I was off by half a pixel, which is why mine seems to sort of jump around.


Edited by Hatch - 19 March 2010 at 4:02pm