TRSRect defines a rectangle, with coordinates in floating points.
TRSRect represents the location and dimensions of a rectangle. The coordinates are specified as either four separate Single coordinates representing the left, top, right, and bottom sides, or as two points representing the locations of the upper-left and lower-right corners.
Typically, TRSRect values represent pixel locations, where the origin of the pixel coordinate system is in the upper-left corner of the screen (screen coordinates) or the upper-left corner of a control's client area (client coordinates). When a TRSRect value represents a rectangle on the screen, by convention, the top and left edges are considered inside the rectangle and the bottom and right edges are considered outside the rectangle. This convention allows the width of the rectangle to be Right - Left and the height to be Bottom - Top.