This was Kaiochao's problem but he's a lazy butt and won't write up a bug report for it, so I'm doing it for him.
Using rotations, and potentially scaling, with the new atom.transform will result in some displayed pixels along the edges of an icon that are interpolated between a solid color pixel and a mask pixel. These pixels will show up as a sort of gray outline around the icon, and they are not transparent.
This outline is gray probably because the default mask is gray, so it uses the mask color of whichever icon the atom happens to use.
Numbered Steps to Reproduce Problem:
1. put an atom down whose icon has a number of mask pixels and solid pixels.
2. rotate that thang gurl.
Code Snippet (if applicable) to Reproduce Problem:
var/atom/movable/test = new(locate(1,1,1))
test.icon = testIcon //where testIcon has solid pixels and mask pixels
animate(test, transform = turn(matrix(), 120), time = 2, loop = 5)
smooth rotation with no jaggies or artifacts
gray outline around the test atom.
Does the problem occur:
Every time? Or how often?
In other games?
In other user accounts?
On other computers?
When does the problem NOT occur?
The problem is less noticeable if you change the mask to a color that doesn't contrast so much with whatever turf icon you're using.
Did the problem NOT occur in any earlier versions? If so, what was the last version that worked? (Visit http://www.byond.com/download/build to download old versions for testing.)
Problem is not applicable to earlier versions.
Change the mask color of the icon. Use the same color for all turfs. What a crappy workaround.