Backdrop and resizable/movable frames

[MunkDev]

I have a frame using this backdrop:

local Backdrop = {
   bgFile      = db.PATH.."BackdropBG",
   edgeFile    = db.PATH.."BackdropEdge",
   edgeSize    = 8,
   insets      = {left = 8, right = 8, top = 8, bottom = 8}
}

The edge file is made up of 8x8 tiles and is correctly configured, however, when the frame can be moved and resized, the backdrop doesn't always draw correctly. Any idea why this is happening, and if so, a way to circumvent or even prevent it?

It looks like it moves one line from the top edge to the bottom edge, or occassionally it moves a line from the left edge to the right edge.

Correct:


Incorrect:

[MunkDev]

Here's a gif, vaguely showing the issue inside a moving scrollframe:

Quality is bad, but good enough to spot the flickering edge file.

[myrroddin]

That gif is hard to follow with the bouncing. It is just better to post with the code tags or Lua button.

Anyway, the error is simple: loc1 is presumably undefined, or if it is, your assignment of it is incorrect. Depending on what you want (can't see the rest of your code):

loc1 = 11
-- or
loc1 = loc1 + 11

[Lombra]

Originally Posted by myrroddin That gif is hard to follow with the bouncing. It is just better to post with the code tags or Lua button. Anyway, the error is simple: loc1 is presumably undefined, or if it is, your assignment of it is incorrect. Depending on what you want (can't see the rest of your code): loc1 = 11 -- or loc1 = loc1 + 11

You didn't really read the thread at all, did you? :P

[MunkDev]

Originally Posted by myrroddin That gif is hard to follow with the bouncing. It is just better to post with the code tags or Lua button. Anyway, the error is simple: loc1 is presumably undefined, or if it is, your assignment of it is incorrect. Depending on what you want (can't see the rest of your code): loc1 = 11 -- or loc1 = loc1 + 11

Lol! This is a lua IDE I'm working on. The error is intended to draw the error tooltip, which has the graphical error I can't figure out. I didn't think the OP was that wordy?

[Lombra]

Originally Posted by MunkDev Lol! This is a lua IDE I'm working on. The error is intended to draw the error tooltip, which has the graphical error I can't figure out. I didn't think the OP was that wordy?

Didn't realise you were referring to the tooltip in that GIF! That looks like it could be plain old aliasing from it being drawn on fractions of pixels.

[Gethe]

This is a general issue with single pixel lines. As the tooltip moves, the border will occasionally get between pixels which results in that line becoming dimmer.

One way you can work around this is ensuring that 1) both the width and height are whole numbers and 2) the frame is positioned on whole pixels. Using floor() and/or ceil() can help in both cases.

Also, if you're not anchoring corner to corner, you may need to add .5.

[ObbleYeah]

I've used

UIParent:GetScale()/frame:GetEffectiveScale()

to fix borders with this issue on corner to corner offsets