Sets a point on canvas from which transformations are calculated. For example, a layer may rotate around its center axis or a completely custom point, such as one of its corners. The three values represent the X, Y and Z axes in 3D space. Apart from the pixel and percentage values, you can also use the following constants: top, right, bottom, left, center, slidercenter, slidermiddle, slidertop, sliderright, sliderbottom, sliderleft.