How to reduce image size without pixelation?

Question

I see lots of games with smooth edges characters and high res images, however when I try to reduce images to say 64x64 for my character I just get a pixelated mess. even if I start with a 64x64 canvas I get pixelated edges.

Should I be scaling with OpenGL? or is there some technique perhaps with photoshop or pixen that I am unaware of?

From your description, it would seem that the scaling algorithm you're using does nearest-pixel interpolation rather than the smoother Lanczos interpolation. Is that question about scaling down vector art helpful? — Anko, May 03 '13 at 22:06

Anko · Accepted Answer · 2013-05-03T23:11:41.373

27

Sounds like the scaling algorithm you're using isn't interpolating pixels.

Pictures are best explained with pictures:

scaling an image with different interpolations

It's the Major, first in full, then scaled down with Lanczos (left) and nearest-pixel (a.k.a. no interpolation) (right) to two sizes.

The same comparison, in 3x magnified:

detail view

Make sure the scaling you're using is resampling sensibly. For example, ImageMagick has a -filter Lanczos option.

It doesn't even need to be fancy Lanczos, in case your tools can't do it; cubic (leftmost) looks the same to me:

cubic on the left

edited May 03 '13 at 23:11

answered May 03 '13 at 22:59

Anko

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Thanks for taking the time to answer and show examples images. Much appreciated. – Rhys May 08 '13 at 19:31

How to reduce image size without pixelation?

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