Call the Graphics object's FillPath method to fill the text path with blue. Then call the Graphics object's SetClip method to make the object use the path as its clipping path.

Now draw lines that fill the form, gradually changing their colors to form the gradient.

Private Sub Form1_Paint(ByVal sender As Object, ByVal e As _
    System.Windows.Forms.PaintEventArgs) Handles _
    MyBase.Paint
    Dim text_path As GraphicsPath

    ' Create the text path.
    text_path = New System.Drawing.Drawing2D.GraphicsPath( _
        Drawing.Drawing2D.FillMode.Alternate)
    text_path.AddString("Flowers", _
        New FontFamily("Times New Roman"), _
        FontStyle.Bold, 200, _
        New Point(10, 10), _
        StringFormat.GenericDefault)

    ' Fill the path with blue.
    e.Graphics.FillPath(New SolidBrush(Color.Blue), _
        text_path)

    ' Use the path as the Graphics
    ' object's clipping region.
    e.Graphics.SetClip(text_path)

    ' Draw lines on the form.
    Dim dg As Single
    Dim g As Single
    Dim y As Integer
    dg = -255 / (Me.Height + 1)
    g = 255
    For y = 0 To Me.Height
        e.Graphics.DrawLine( _
            New Pen(Color.FromArgb(255, 0, g, 0), 2), _
            0, y, 1000, y)
        g += dg
    Next y
End Sub