Place circle at mouse position in picture box - vb.net

Question

I have done a lot of searching and cannot find the help that I need.
I need to be able place some circles with diameter of 140 pixels over some sections of an image in a picturebox. The circles should appear when the mouse is clicked on the image. I need the centre of the circle to be placed at the position of the mouse when it is clicked.The user should also be able to drag the circle to a different position once it is placed on the image.
Can anyone give me some guidance on how this is done?
Thanks in advance!

Answer 1

This might start you off. Draws a simple red circle on PictureBox.Click
Private Sub PictureBox1_Click(sender As System.Object, e As MouseEventArgs) Handles PictureBox1.Click
Dim myBrush As New System.Drawing.SolidBrush(System.Drawing.Color.Red)
Dim formGraphics As System.Drawing.Graphics
formGraphics = sender.CreateGraphics()
formGraphics.FillEllipse(myBrush, New Rectangle(e.X / 2, e.Y / 2, 70 , 70))
myBrush.Dispose()
formGraphics.Dispose()
End Sub
EDIT
Looks exaclty like what you are looking for
http://www.dreamincode.net/forums/topic/59049-simple-drawing-selection-shape-or-rubberband-shape/

Answer 2

My solution: `
Private Sub PictureBox1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseDown
'start creating circle when the mouse is clicked
PictureBox1.Refresh() 'erases previous rectangle
Xstart = e.X
Ystart = e.Y
bRB = True
End Sub
Private Sub PictureBox1_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseMove
'drag the circle over the seclected area
If bRB Then
PictureBox1.Refresh() 'erases previous rectangle
Select Case e.X
Case Is < 0
RBRectangle.X = 0
' RBRectangle.Width = Xstart
RBRectangle.Width = 140
Case 0 To Xstart
RBRectangle.X = e.X
'RBRectangle.Width = Xstart - e.X
RBRectangle.Width = 140
Case Xstart To PBWidth
RBRectangle.X = Xstart
'RBRectangle.Width = e.X - Xstart
RBRectangle.Width = 140
Case Is > PBWidth
RBRectangle.X = Xstart
'RBRectangle.Width = PBWidth - Xstart
RBRectangle.Width = 140
End Select
Select Case e.Y
Case Is < 0
RBRectangle.Y = 0
'RBRectangle.Height = Ystart
RBRectangle.Height = 140
Case 0 To Ystart
RBRectangle.Y = e.Y
'RBRectangle.Height = Ystart - e.Y
RBRectangle.Height = 140
Case Ystart To PBHeight
RBRectangle.Y = Ystart
'RBRectangle.Height = e.Y - Ystart
RBRectangle.Height = 140
Case Is > PBHeight
RBRectangle.Y = Ystart
'RBRectangle.Height = PBHeight - Ystart
RBRectangle.Height = 140
End Select
PictureBox1.CreateGraphics.DrawEllipse(RBPen, RBRectangle)
End If
End Sub
Private Sub PictureBox1_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseUp
'show the area in the rectangle as a new image
Dim CroppedBm As Bitmap
If bRB Then
bRB = False
CroppedBm = New Bitmap(RBRectangle.Width, _
RBRectangle.Height)
End If
End Sub

Answer 3

Try this:
Dim g As Graphics
Dim md As Boolean
Private Sub Form1_Load() Handles MyBase.Load
g = PictureBox1.CreateGraphics
End Sub
Private Sub PictureBox1_MouseClick(sender As Object, e As MouseEventArgs) Handles PictureBox1.MouseClick
PictureBox1.Refresh()
g.DrawEllipse(Pens.Red, New Rectangle(e.X - 35, e.Y - 35, 70, 70))
End Sub
Private Sub PictureBox1_MouseDown(sender As Object, e As MouseEventArgs) Handles PictureBox1.MouseDown
md = True
End Sub
Private Sub PictureBox1_MouseMove(sender As Object, e As MouseEventArgs) Handles PictureBox1.MouseMove
If md Then
PictureBox1.Refresh()
g.DrawEllipse(Pens.Red, New Rectangle(e.X - 35, e.Y - 35, 70, 70))
End If
End Sub
Private Sub PictureBox1_MouseUp(sender As Object, e As MouseEventArgs) Handles PictureBox1.MouseUp
md = False
End Sub