Why is my code to rotate individual images in VB 2008 GDI+ not working?

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I have a list of meteors that I need to rotate individually depending on the rotation speed.
Despite everything I have tried, it doesn't rotate at all.
Note: The image is scaled up by 2.

VB

Private Sub Form1_Paint5(ByVal sender As Object, ByVal e As  _
    System.Windows.Forms.PaintEventArgs) Handles MyBase.Paint

    For Each I As Meteor In Meteors ' Rotate Meteors and draw meteors
        e.Graphics.Transform.RotateAt(5, New Point(I.Pos.X + I.Type.Width, I.Pos.Y + I.Type.Height))
        e.Graphics.DrawImage(I.Type, I.Pos.X, I.Pos.Y, I.Type.Width * 2, I.Type.Height * 2)
    Next
End Sub

Posted 31-Oct-13 6:45am

Santiago Moreno

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Ron Beyer · Accepted Answer · 2013-10-31T08:22:00

Because Graphics.Transform returns a copy of the transformation matrix, not the matrix being used. In order to do what you want, you would need to do something like this:

VB

'Inside your loop
e.Graphics.Transform = e.Graphics.Transform.RotateAt(5 ...)

But you would want to save your graphics state between rotations so the previous rotation does not affect the next one, you do this by saving the GraphicsState and restoring it.

VB

Dim graphicsState as GraphicsState = e.Graphics.Save()
'do your transformation here, then draw your image
e.Graphics.Restore(graphicState)