VB.NET 1.1 Tutorial - GDI+ - Part 4 - Rectangles

In this part we will look at some simple applications that utilise the methods DrawRectangle and FillRectangle.

Drawing Rectangles

There are two methods of drawing a rectangle. The first two versions of the DrawRectangle method takes five parameters. The syntax for the method definition is:

Public Sub DrawRectangle( _
  ByVal pen As Pen, _
  ByVal x As Integer, _
  ByVal y As Integer, _
  ByVal width As Integer, _
  ByVal height As Integer _
)

Public Sub DrawRectangle( _
  ByVal pen As Pen, _
  ByVal x As Single, _
  ByVal y As Single, _
  ByVal width As Single, _
  ByVal height As Single _
)

Where the Parameters are:

pen - Pen object that determines the color, width, and style of the arc.
x - x-coordinate of the upper-left corner of the rectangle to draw.
y - y-coordinate of the upper-left corner of the rectangle to draw.
width - Width of the rectangle to draw.
height - Height of the rectangle to draw.

These methods draw a rectangle specified by a coordinate pair, a width, and a height.

We will create a simple example to draw a rectangle on the form.

Private Sub RectangleDemo_Paint( ByVal sender As Object, _
                                 ByVal e As PaintEventArgs) _
                                 Handles MyBase.Paint

  ' Get Graphics Object
  Dim g As Graphics = e.Graphics

  ' Create Pen
  Dim myPen As New Pen( Color.Blue, 2 )

  ' Draw rectangle to screen
  g.DrawRectangle( myPen, 10, 10, 220, 150 )

  ' Now tidy up
  myPen.Dispose()
End Sub

This code gives the following output:

You can download the file rect01.vb from the link, or you can download my copy of the executable from here.

Rectangles using `Rectangle`

The other method uses a Rectangle structure to draw a rectangle. So to create the same rectangle as before, the code would like this.

Private Sub RectangleDemo_Paint( ByVal sender As Object, _
                                 ByVal e As PaintEventArgs) _
                                 Handles MyBase.Paint

  ' Get Graphics Object
  Dim g As Graphics = e.Graphics

  ' Create Pen
  Dim myPen As New Pen( Color.Blue, 2 )

  ' Create rectangle
  Dim rect As New Rectangle( 10, 10, 220, 150 )

  ' Draw rectangle to screen
  g.DrawRectangle( myPen, rect )

  ' Now tidy up
  myPen.Dispose()
End Sub

Filling Rectangles

The FillRectangle method is similar to the DrawRectangle method. There are essentially two ways of using the FillRectangle method. The first two versions take a brush and four integers or floating-point values. The other two versions take a brush and a Rectangle or RectangleF structure.

Below is the code to draw a filled rectangle of the same size as before.

Private Sub RectangleDemo_Paint( ByVal sender As Object, _
                                 ByVal e As PaintEventArgs) _
                                 Handles MyBase.Paint

  ' Get Graphics Object
  Dim g As Graphics = e.Graphics

  ' Create Brush
  Dim myBrush As New SolidBrush( Color.Blue )

  ' Draw rectangle to screen
  g.FillRectangle( myBrush, 10, 10, 220, 150 )

  ' Now tidy up
  myBrush.Dispose()
End Sub

You can download the file rect02.vb from the link, or you can download my copy of the executable from here.

References

For more information on the DrawRectangle Method, visit MSDN at microsoft here.

For more information on the FillRectangle Method, visit MSDN at microsoft here.

What Next?

Next we will draw some simple Ellipses.