What does turning alpha on and then off again do?

[snibgo]

Upthread, I said I reported the OP situation as a bug. But I was wrong; it isn't.

The reason "-alpha off" makes a slightly different resize, even for images that are fully opaque, is that IM uses a different default filter. I suggest that if you prefer the result from "-alpha off", you remove that (and the "-alpha on") and instead use an explicit "-filter":

Code: Select all

convert.exe input.tga -filter Lanczos -resize 128x128! output.tga

[fmw42]

If you are trying to resize pixel art, then

see -magnify for pixel art 2x scaling

http://www.imagemagick.org/script/comma ... hp#magnify

viewtopic.php?f=22&t=23046

also
viewtopic.php?f=1&t=17447&p=65637&hilit=scale2x#p65637