RectSlice

Represents a 2D slice in an integral space inside a base (or atlas) that has a width and height.

The rect property represents the slice inside that base/container, as it is stored without any kind of transformation.

Then there is a orientation that described how that slice should be interpreted. Should it be rotated or flipped later?

The coords represents a ratio (0-1) coordinates inside the base/container with the swapped coordinates applying the orientation. The unorientedCoords represents a ratio (0-1) coordinates inside the base/container without applying the orientation.

Then the padding describes, the padding that will have the rect after applying the orientation to represent the original sliced region. virtFrame represents the region including the oriented width and height and the padding.

Typically, this slice represents a slice inside a Bitmap or a Texture atlas, that might have been stored rotated, flipped, etc. and sometimes it might have been cropped.