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.NET Structures: The Rectangle

 

Description

A rectangle is a geometric figure that has four sides. To support this figure, the System.Drawing namespace provides the Rectangle and the RectangleF structures. A rectangle can be represented as follows:

Rectangle

Like every geometric representation in your program, a rectangular figure is based on a coordinate system whose origin is located on a top-left corner. The object that "owns" or defines the rectangle also owns this origin. For example, if the rectangle belongs to a control that is positioned on a form, then the origin is on the top-left corner just under the title bar of the form, provided the form has a title bar.

To completely represent it, a rectangle is defined by its location and its dimensions. The location is defined by a point on the top-left corner of the rectangle. The distance from the left border of the object that owns the rectangle to the left border of the rectangle is represented by a property called Left. The distance from the top border of the object that owns the rectangle to the top border of the rectangle is represented by a property called Top. The distance from the left to the right borders of the rectangle is represented by a property called Width. The distance from the left to the right borders of the rectangle is represented by a property called Height. The distance from the left border of the object that owns the rectangle to the right border of the rectangle is represented by a property called Right. The distance from the top border of the object that owns the rectangle to the bottom border of the rectangle is represented by a property called Bottom. Based on this, a rectangle can be illustrated as follows:

Rectangle Representation

 

To create a rectangle, you must provide at least its location and dimensions. The location can be represented by a Point value and the dimensions can be represented with a Size value. Based on this, you can use the following constructor to declare a Rectangle variable:

Public Sub New(location As Point, size As Size)

This constructor requires that you define a Point and a Size in order to use it. If instead you know the integer values of the location and dimensions, you can use the following constructor to declare a Rectangle object:

Public Sub New(x As Integer, y As Integer, width As Integer, height As Integer)

At any time, you can access or retrieve the characteristics of a Rectangle object as illustrated in the above picture from its properties. You use the same names we used in the picture.

Besides the Rectangle structure, the System::Drawing namespace provides the RectangleF structure that uses the same definition as Rectangle, except that it is defined with float values instead of integers.

 

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