Create dot and line manual with VB

Private Sub Blue_Click(Index As Integer)
Form1.ForeColor = vbBlue
End Sub
Private Sub full_Click()
Form1.WindowState = FormWindowState.Maximized
End Sub

Private Sub Default_Click(Index As Integer)
Form1.ForeColor = vbBlack
End Sub

Private Sub opsiGreen_Click(Index As Integer)
Form1.ForeColor = vbGreen
End Sub
Private Sub opsiRed_Click(Index As Integer)
Form1.ForeColor = vbRed
End Sub
Sub garis(x1, y1, x2, y2)
dx = x2 - x1
dy = y2 - y1

If x2 < x1 And y2 < y1 Then
    dx = x1 - x2
    dy = y1 - y2
End If

If x2 < x1 And y2 = y1 Then
    dx = x1 - x2
End If

If y2 < y1 And x2 = x1 Then
    dy = y1 - y2
End If

If dx > dy Then
    l = dx
Else
    l = dy
End If

If x2 < x1 And y1 = y2 Then
    dx = dx - 2 * dx
End If

If y2 < y1 And x1 = x2 Then
    dy = dy - 2 * dy
End If


If dx = 0 Then
    incx = 0
Else
    incx = dx / l
End If

If dy = 0 Then
    incy = 0
Else
    incy = dy / l
End If

x = x1
y = y1


If x2 < x1 And y2 < y1 Then
x = x2
y = y2
End If


For i = 1 To l
Form1.PSet (x, y)
x = x + incx
y = y + incy
Next i
End Sub
Private Sub sumbuX_KeyPress(KeyAscii As Integer)
 If KeyAscii = 13 Then
        Form1.Cls
        Form1.PSet (sumbuX, sumbuY)

        Form1.PSet (sumbuX, sumbuY + 2)
        Form1.PSet (sumbuX, sumbuY - 2)
        Form1.PSet (sumbuX - 2, sumbuY)
        Form1.PSet (sumbuX + 2, sumbuY)
    End If
End Sub
Private Sub sumbuX1_KeyPress(KeyAscii As Integer)
If KeyAscii = 13 Then
    x1 = Int(sumbuX1.Text)
    y1 = Int(sumbuY1.Text)
    x2 = Int(sumbuX2.Text)
    y2 = Int(sumbuY2.Text)
    Form1.Cls
    Call garis(x1, y1, x2, y2)
End If
End Sub
Private Sub sumbuX2_KeyPress(KeyAscii As Integer)
If KeyAscii = 13 Then
    x1 = Int(sumbuX1.Text)
    y1 = Int(sumbuY1.Text)
    x2 = Int(sumbuX2.Text)
    y2 = Int(sumbuY2.Text)
    Form1.Cls
    Call garis(x1, y1, x2, y2)
End If
End Sub

Private Sub sumbuY_KeyPress(KeyAscii As Integer)
    If KeyAscii = 13 Then
        Form1.Cls
        Form1.PSet (sumbuX, sumbuY)
        Form1.PSet (sumbuX, sumbuY + 2)
        Form1.PSet (sumbuX, sumbuY - 2)
        Form1.PSet (sumbuX - 2, sumbuY)
        Form1.PSet (sumbuX + 2, sumbuY)
    End If
End Sub
Private Sub sumbuY1_KeyPress(KeyAscii As Integer)
If KeyAscii = 13 Then
    x1 = Int(sumbuX1.Text)
    y1 = Int(sumbuY1.Text)
    x2 = Int(sumbuX2.Text)
    y2 = Int(sumbuY2.Text)
    Form1.Cls
    Call garis(x1, y1, x2, y2)
End If
End Sub
Private Sub sumbuY2_KeyPress(KeyAscii As Integer)
If KeyAscii = 13 Then
    x1 = Int(sumbuX1.Text)
    y1 = Int(sumbuY1.Text)
    x2 = Int(sumbuX2.Text)
    y2 = Int(sumbuY2.Text)
    Form1.Cls
    Call garis(x1, y1, x2, y2)
End If
End Sub