Imports System
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Data
Imports System.Drawing
Imports System.Linq
Imports System.Text
Imports System.Windows.Forms
Public Class Form1

     Private Sub Form1_Paint(ByVal sender As System.Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint
        Dim g As Graphics = e.Graphics

        'Create color object from ARGB
        Dim redColor As Color = Color.FromArgb(120, 255, 0, 0)

        'Create Color Object from color name
        Dim blueColor As Color = Color.FromName("Blue")

        'Create Color object from known color
        Dim greenColor As Color = Color.FromKnownColor(KnownColor.Green)

        'Create Empty Color
        Dim tstColor As Color = Color.Empty

        'See if a color is empty

        If tstColor.IsEmpty Then
            tstColor = Color.DarkGoldenrod
        End If
 
        'Create brushes and pens from colors
        Dim redBrush As New SolidBrush(redColor)
        Dim blueBrush As New SolidBrush(blueColor)
        Dim greenBrush As New SolidBrush(greenColor)
        Dim greenPen As New Pen(greenBrush, 4)

        'Draw GDI+ objects
        g.FillEllipse(redBrush, 10, 10, 50, 50)
        g.FillRectangle(blueBrush, 60, 10, 50, 50)
        g.DrawLine(greenPen, 20, 60, 200, 60)

        'Check property values
        'MessageBox.Show ("Color Name:"+blueColor.Name+
        ' ", A:"+ blueColor.A.ToString () +
        ' ", R:"+ blueColor.R.ToString () +
        ' ", B:" + blueColor.B.ToString () +
        ' ", G:"+ blueColor.G.ToString ());
        'Dispose of GDI+ objects
        redBrush.Dispose()
        blueBrush.Dispose()
        greenBrush.Dispose()
        greenPen.Dispose()
        g.Dispose()
    End Sub

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        'Create Graphics object
        Dim g As Graphics = Me.CreateGraphics()

        'Create color object from ARGB
        Dim redColor As Color = Color.FromArgb(120, 255, 0, 0)

        'Create Color Object from color name
        Dim blueColor As Color = Color.FromName("Blue")

        'Create Color object from known color
        Dim greenColor As Color = Color.FromKnownColor(KnownColor.Green)

        'Create Empty Color
        Dim tstColor As Color = Color.Empty

        'See if a color is empty

         If tstColor.IsEmpty Then
            tstColor = Color.DarkGoldenrod
        End If

        'Create brushes and pens from colors
        Dim redBrush As New SolidBrush(redColor)
        Dim blueBrush As New SolidBrush(blueColor)
        Dim greenBrush As New SolidBrush(greenColor)
        Dim greenPen As New Pen(greenBrush, 4)

        'Draw GDI+ objects
        g.FillEllipse(redBrush, 10, 10, 50, 50)
        g.FillRectangle(blueBrush, 60, 10, 50, 50)
        g.DrawLine(greenPen, 20, 60, 200, 60)
 
        'Check property values
        'MessageBox.Show ("Color Name:"+blueColor.Name+
        ' ", A:"+ blueColor.A.ToString () +
        ' ", R:"+ blueColor.R.ToString () +
        ' ", B:" + blueColor.B.ToString () +
        ' ", G:"+ blueColor.G.ToString ());
        'Dispose of GDI+ objects
        redBrush.Dispose()
        blueBrush.Dispose()
        greenBrush.Dispose()
        greenPen.Dispose()
        g.Dispose()
    End Sub
End Class
 

The GetBrightness, GetHue, and GetSaturation method return a color's brightness, hue, and saturation component values, respectively. Listing 5.2 reads hue, saturation, and brightness components of a color and displays their values on the form by using the DrawString method.
 

 

FIGURE 5.1 Creating colors using different methods

 

LISTING 5.2: Getting brightness, hue, and saturation of a color

    Private Sub HSBMenu_Click(ByVal sender As Object, ByVal e As System.EventArgs)
        'Create a Graphics object
        Dim g As Graphics = Me.CreateGraphics()

        'Create a color
        Dim clr As Color = Color.FromArgb(255, 200, 0, 100)

        'Get hue, saturation, and brightness components
        Dim h As Single = clr.GetHue()
        Dim s As Single = clr.GetSaturation()
        Dim v As Single = clr.GetBrightness()
        Dim str As String = (("Hue:" & h.ToString() & vbLf & "Saturation: ") + s.ToString() & vbLf & "Brightness: ") + v.ToString()

        'Display data
        g.DrawString(str, New Font("Verdana", 12), Brushes.Blue, 50, 50)

        'Dispose of object
        g.Dispose()
    End Sub

Figure 5.2 shows the output from Listing 5.2.The values of hue, saturation, and brightness in this particular color are 330, 1, and 0.3921569, respectively.
 

 

FIGURE 5.2: Getting brightness, hue and saturation components of a color

Conclusion

Hope the article would have helped you in understanding Colors, Fonts, and Text in GDI+. Read other articles on GDI+ on the website.