UI Scale

UI Scale is enabled from the Main Menu in the "Video Options" section under "Resolution". From here, you must enable "UI Scale" in order to take advantage of this feature. As outlined in UI Coordinates, UI Scale is normalized to a height of 768px regardless of actual screen resolution. UI Scale is the frontend extension of that to the user.

To demonstrate, let's assume we have a texture onscreen that is 256x256 pixels large. If the actual y-res matches the WoW y-res (e.g., 1024x768 = 768) then our texture will show as 256px (768/768 = 1*256 = 256). As we increase our resolution, so does our multiplier ([actual y/WoW y] = multiplier). Observe the following (all results are with the same 256x256 texture):

A couple points of interest:
 * The UI Scale goes from 1 to 0.64. At 768y we see pixel-per-pixel accurate representation of our texture, and again at 1200y if at 0.64 scale.
 * When UI Scale is turned off, the Scale Off Multiplier changes gradually and is not initially a constant.
 * In each case after 768y, unless the UI Scale is enabled, your texture will be overblown past its intended size. Given that these higher resolutions show more detail, your textures will appear successively worse.