Pan Image with click and drag

Someone on MSDN asked a question about clicking and draging an image to pan around while zoomed. The control already did the zoom and consists of a picturebox within a panel with autoscroll turned on. This would let you use the scrollbars to navigate, but the poster wanted to pan by dragging so here it is. I will add to it as needed but this seemed to work pretty well.


Public Class Form1
Dim x1, y1 As Double
Dim scrollSensitivity As Double
Dim md As Boolean
Private Sub PictureBox1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseDown
md = True
x1 = Me.Panel1.HorizontalScroll.Value
y1 = Me.Panel1.VerticalScroll.Value
End Sub
Private Sub PictureBox1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseMove
scrollSensitivity = 4
If md = True Then
Try
Me.Panel1.HorizontalScroll.Value = (e.X - x1) / scrollSensitivity
Me.Panel1.VerticalScroll.Value = (e.Y - y1) / scrollSensitivity
Catch ex As Exception
End Try
End If
End Sub
Private Sub PictureBox1_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseUp
md = False
End Sub
End Class