How do I prevent Graphics.DrawImage from scaling the picture? - vb.net

Question

I am using a code that creates an image tooltip when the user hovers over the button. However, for some reason, for some of the buttons, the image gets scaled larger and doesnt completely fit in the tooltip window. I have no idea why some images are getting scaled and not others. Here is the code:
Protected Overrides Sub OnLoad(e As EventArgs)
MyBase.OnLoad(e)
ToolTip1.OwnerDraw = True
For Each ctrl As Control In Controls
If TypeOf ctrl Is Button Then
ToolTip1.SetToolTip(ctrl, " ")
End If
Next
End Sub
Private Sub ToolTip1_Popup(sender As Object, e As PopupEventArgs) Handles ToolTip1.Popup
Dim oTemplate As String = e.AssociatedControl.Name
Dim ButtonPic As Image = Image.FromFile(System.IO.Path.GetFullPath("TemplatesResources\MouseHoverPics\" & oTemplate & ".png"))
e.ToolTipSize = New Size(ButtonPic.Size.Width, ButtonPic.Size.Height)
End Sub
Private Sub ToolTip1_Draw(sender As Object, e As DrawToolTipEventArgs) Handles ToolTip1.Draw
Dim oTemplate As String = e.AssociatedControl.Name
Dim ButtonPic As Image = Image.FromFile(System.IO.Path.GetFullPath("TemplatesResources\MouseHoverPics\" & oTemplate & ".png"))
e.Graphics.Clear(SystemColors.Info)
e.Graphics.DrawImage(ButtonPic, New System.Drawing.Point(0, 0))
End Sub
The results:
Looking good at first.
Scaling begins....
Even more scaling the further right I go... could it possibly have to do with the button placement? I cant see why the code would take that into consideration
Any help would be appreciated.

Answer 1

That happens because when you call
e.ToolTipSize = New Size(ButtonPic.Size.Width, ButtonPic.Size.Height)
you set [size of the popup = size of the image]. But what happens if you don't have enough space between your mouse cursor and the border of the window? The popup resize itself, and when you load the image inside of it, the image scale itself to match the current width/height
e.Bounds()
So all you have to do is to check the Bounds of the popup and scale manteining the ratio before call DrawImage() method.
Here's and example
Private Sub ToolTip1_Draw(sender As Object, e As DrawToolTipEventArgs) Handles ToolTip1.Draw
Dim oTemplate As String = e.AssociatedControl.Name
Dim ButtonPic As Image = Image.FromFile(System.IO.Path.GetFullPath("TemplatesResources\MouseHoverPics\" & oTemplate & ".png"))
e.Graphics.Clear(SystemColors.Info)
If ButtonPic.Width > e.Bounds.Widht Or ButtonPic.Height > e.Bounds.Height Then
[code to rescale, make it as you prefer]
End If
e.Graphics.DrawImage(ButtonPic, New System.Drawing.Point(0, 0))
End Sub