LeftRightWidths
Vec2 = [0.25, 0.25] Width of the left and of the right cap on screen, in pixels of the icon's layout.
A horizontal three-slice atlas provider: the sprite is cut into a left cap, a middle and a right cap. The caps keep their width and the middle stretches, so a bar or a button can be any width. All three pieces stretch to the icon's full height.
Slicing and the scaling of the edge sizes are described on IUiTextureDataProvider.
Vec2 = [0.25, 0.25] Width of the left and of the right cap on screen, in pixels of the icon's layout.
Vec4 = [0, 0.25, 0.75, 1] The four column boundaries, left to right, in pixels of the source resolution: the left edge of the sprite, the two cuts, and the right edge.
Vec2 = [0, 1] The top and the bottom of the sprite, in pixels of the source resolution.