Itextsharp. Text. rectangle

During the use of itextsharp. Text. rectangle, due to the small amount of Chinese data in this field, it causes a lot of inconvenience and consumes working time,

The constructor of itextsharp. Text. rectangle is as follows:PublicRectangle (FloatLLX,FloatLly,FloatUrx,FloatURY );

The Parameter Name of the constructor does not mean anything at all. Although we can see from the semantics of rectangle that it defines a region, however, I don't know where the coordinates of these four parameters are, so if I don't clear the meaning of these four parameters, there will be many unexpected situations and you will be overwhelmed.

Public Rectangle ( Float LLX, Float Lly, Float Urx, Float URY );
LLX is left, lly is bottom, urx is right, and Ury is top
Where: width = right-left heigth = Top-bototom
Coordinate origin: lower left