Question: I have a stupid question:

I have a black circle on white background, something like:

![enter image description here](https://i.stack.imgur.com/DQLPv.gif)

I have a code in Matlab that gets an image with a black circle and returns the number of pixels in the circle.

**will I get the same number of pixels in a camera of 5 mega pixel and a camera of 8 mega pixel?**

Answer: 
Set these propeties:

```
yourTooltip.OwnerDraw = true; 
yourTooltip.BackColor = System.Drawing.Color.Red;

```

then on the Draw event use this :

```
private void yourTooltip_Draw(object sender, DrawToolTipEventArgs e)
{
    e.DrawBackground();
    e.DrawBorder();
    e.DrawText();
}

```
When you set a Control to OwnerDraw, you have to handle the drawing of the control yourself.

Here's a quick and dirty example (adapt to your taste):

```
Private Sub ToolTip1_Draw(sender As Object, e As DrawToolTipEventArgs) Handles ToolTip1.Draw
    Dim tt As ToolTip = CType(sender, ToolTip)
    Dim b As Brush = New SolidBrush(tt.BackColor)

    e.Graphics.FillRectangle(b, e.Bounds)

    Dim sf As StringFormat = New StringFormat
    sf.Alignment = StringAlignment.Center
    sf.LineAlignment = StringAlignment.Center
    e.Graphics.DrawString(e.ToolTipText, SystemFonts.DefaultFont, SystemBrushes.ActiveCaptionText, e.Bounds, sf)

    sf.Dispose()
    b.Dispose()
End Sub

```

Cheers