ID:120105
 
Resolved
Screen objects that also used pixel movement on the map were offset by their step_x and step_y values, when instead those should be ignored on the HUD.
BYOND Version:493
Operating System:Windows 7 Home Premium 64-bit
Web Browser:Firefox 7.0.1
Applies to:Dream Seeker
Status: Resolved (494)

This issue has been resolved.
Descriptive Problem Summary:
When using pixel movement, if you set a screen_loc on an object that you can also see on the map (ie: yourself) (even if its not in your screen), this will cause graphical lag. This lag is most likely tied to changing the layer of said object once a screen_loc is applied, as discussed in the comments here.

There will also be an undesirable movement effect on the HUD version of the object if you do actually add it to your screen, due to step_x/y.
I'm having a similar issue, instead of lag, objects that are on the screen that get their pixel_x/y changed do nothing. There's no lag, but the pixel_x/y doesn't visually change anything at all. Instead I've resorted to changing screen_loc as an alternative.

I'm not sure if this is how it's supposed to act, but I would assume that pixel_x/y have no bearing on an atoms "physical" position in comparison to it's "visual" position. (I use quotations since technically both positions are entirely visual)
Pixel offsets have no impact on the HUD. Changing screen_loc is the correct way to handle those cases.
Oh, I thought I was doing it half-assed because of a bug. Nevermind then =)
I did not see any lag in action, but the step_x/y issue was a bug. Keeping the same movement state as the original object I think fits legacy behavior and has not been changed.
Lummox JR resolved issue with message:
Screen objects that also used pixel movement on the map were offset by their step_x and step_y values, when instead those should be ignored on the HUD.