Transform point of reference
Specify the point of reference for the transform operation.
This property expects two values for 2D transformations, and three values for 3D transformations. The first two values may be a percentage, a distance, or one of the keywords that specify an edge. The third value must be a distance.
For 2D transformations, the first value is the offset from the element's left edge to the transformation's X origin. For convenience, these keywords may be used:
|left||Use the left-edge as the X origin|
|center||Use the middle of the element as the X origin|
|right||Use the right-edge as the X origin|
For 2D transformations, the second value is the offset from the element's top edge to the transformation's Y origin. For convenience, these keywords may be used:
|top||Use the top-edge as the Y origin|
|center||Use the middle of the element as the Y origin|
|bottom||Use the bottom-edge as the Y origin|
For 3D transformations, the third value is the offset from the plane of the screen to the user's point of reference, expressed as a distance (never a percentage).