Pivot: Its center point, the icon is a small blue dot. Indicates the point at which the picture is calculated to calculate the coordinate value. The default is the geometric center point of the UI element (0.5, 0,5).
Anchor: Anchor Point, Icon is four small triangles. Indicates where the UI element is used as the zoom reference for the parent object, and the anchor point cannot be selected outside the parent container. When the parent object is scaled, it affects the scaling of the sub-object, and when the anchor point is 4 points apart, the distance between the four vertices of the image and the anchor point remains unchanged at the time of scaling, and the position of the anchor point is controlled to control the zoom mode.
Posx,posy: The center point itself is anchored to the coordinate value of the origin (based on the anchor point), and must be anchored to 4 small triangles to merge at one point before this property appears. Left,right,top,bottom: This property appears when the anchor point itself is not gathered at one o'clock, representing the distance from four sides of the UI element to the anchor point.
"Unity Note" Ugui object's Rect transform component (Pivot center point, anchor Anchor Point)