Option Explicit
 
'   //  GetSystemMetrics
Const SM_CXSCREEN = 0 'X Size of screen
Const SM_CYSCREEN = 1 'Y Size of Screen
'   //  CreatePen
Const PS_DOT = 2
Const PS_SOLID = 0
'   //  Apis
Private Declare Function GetDC Lib "user32" (ByVal hWnd As Long) As Long
Private Declare Function MoveToEx Lib "gdi32" (ByVal hdc As Long, ByVal x As Long, ByVal y As Long, lpPoint As Any) As Long
Private Declare Function LineTo Lib "gdi32" (ByVal hdc As Long, ByVal x As Long, ByVal y As Long) As Long
Private Declare Function Ellipse Lib "gdi32" (ByVal hdc As Long, ByVal X1 As Long, ByVal Y1 As Long, ByVal X2 As Long, ByVal Y2 As Long) As Long
Private Declare Function CreatePen Lib "gdi32" (ByVal nPenStyle As Long, ByVal nWidth As Long, ByVal crColor As Long) As Long
Private Declare Function GetSystemMetrics Lib "user32" (ByVal nIndex As Long) As Long
 
Private Declare Function SelectObject Lib "gdi32" (ByVal hdc As Long, ByVal hObject As Long) As Long
Private Declare Function DeleteObject Lib "gdi32" (ByVal hObject As Long) As Long
 
Private Type RECT
    Left As Long
    Top As Long
    Right As Long
    Bottom As Long
End Type
Private Type POINTAPI
    x                   As Long
    y                   As Long
End Type
Private Type tLineas
    PuntoInicio         As POINTAPI
    PuntoFinal          As POINTAPI
End Type
Dim RegionWindows       As RECT
Dim hdcDestino          As Long
 
Private Sub Form_Load()
    Hide
    '   //  Región/Resolución de Pantalla
    With RegionWindows
        .Bottom = GetSystemMetrics(SM_CYSCREEN)
        .Left = 1
        .Right = GetSystemMetrics(SM_CXSCREEN)
        .Top = 1
    End With
    hdcDestino = GetDC(0)
    Timer1.Interval = 100
    Timer1.Enabled = True
End Sub
 
Private Sub Timer1_Timer()
Dim Linea               As tLineas
Dim hPen                As Long
    '   //  Dibujamos lineas al Azar
        '   //  Calculamos el Punto de Inicio
    Linea.PuntoInicio.x = NumeroAleatorio(RegionWindows.Left, RegionWindows.Right)
    Linea.PuntoInicio.y = NumeroAleatorio(RegionWindows.Top, RegionWindows.Bottom)
        '   //  Calculamos el Punto Final
    Linea.PuntoFinal.x = NumeroAleatorio(RegionWindows.Left, RegionWindows.Right)
    Linea.PuntoFinal.y = NumeroAleatorio(RegionWindows.Top, RegionWindows.Bottom)
    '   //  Dibujamos la Linea
    '   //  Dibujamos los puntos    Inicio y Final en color rojo
        '   //  Color de la Linea
        hPen = CreatePen(PS_SOLID, 1, vbRed)
        SelectObject hdcDestino, hPen
        Ellipse hdcDestino, Linea.PuntoInicio.x - 2, Linea.PuntoInicio.y - 2, Linea.PuntoInicio.x + 2, Linea.PuntoInicio.y + 2
        Ellipse hdcDestino, Linea.PuntoFinal.x - 2, Linea.PuntoFinal.y - 2, Linea.PuntoFinal.x + 2, Linea.PuntoFinal.y + 2
        DeleteObject hPen
        '   //  Color de la Linea
        hPen = CreatePen(PS_SOLID, 1, (RGB(NumeroAleatorio(0, 255), NumeroAleatorio(0, 255), NumeroAleatorio(0, 255))))
        SelectObject hdcDestino, hPen
        '   //  Iniciamos una nueva Linea (Punto de Inicio)
        MoveToEx hdcDestino, Linea.PuntoInicio.x, Linea.PuntoInicio.y, ByVal 0&
        '   //  Finalizamos la Linea (Punto Final)
        LineTo hdcDestino, Linea.PuntoFinal.x, Linea.PuntoFinal.y
        DeleteObject hPen
End Sub
Public Function NumeroAleatorio(MinNum As Long, MaxNum As Long) As Long
Dim Tmp                                 As Long
    If MaxNum < MinNum Then: Tmp = MaxNum: MaxNum = MinNum: MinNum = Tmp
    Randomize: NumeroAleatorio = CLng((MinNum - MaxNum + 1) * Rnd + MaxNum)
End Function