Problem changing color and width in drawing program

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  12 years ago

  by Rivhard123

  Richard K Orberson

  , United States

  Joined 12 years ago

  I'm trying to write a basic program for a class project where the user can draw on a panel.  The user can choose which color to use and the width of the pen. I have everything working except if the user decides to draw something in one width and color and than switch to another width and/or color the previously drawn items also change to the new values. I want the previous items to remain as they were and only newly drawn items to take on the new conditions. I have tried a number of things to no avail and could really use some help. I have included my code below for review:

   

  Public Class frmDrawingPad
  
      Dim draw As Boolean = False
      Dim index As Integer = 0  ' sets index for combobox control
      Dim mousePath As New System.Drawing.Drawing2D.GraphicsPath()
      Dim userColor As New Color() 'this is a color the user selects
      Dim penWidth As Single
      Dim rbChecked(3) As RadioButton
  
      Private Sub btnExit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnExit.Click
  
          ' exits program
          Me.Close()
  
      End Sub
  
      Private Sub ExitToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ExitToolStripMenuItem.Click
  
          ' exits program
          Me.Close()
  
      End Sub
  
      Private Sub ClearToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ClearToolStripMenuItem.Click
  
          ' calls procedure that clears panel
          Call ClearDrawingPanel()
  
      End Sub
  
      Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click
  
          ' calls procedure that clears panel
          Call ClearDrawingPanel()
  
      End Sub
  
      Private Sub panelDraw_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles panelDraw.MouseDown
  
          If e.Button = MouseButtons.Left Then ' draw a filled line if left mouse is down 
  
              mousePath.StartFigure()    ' The L mouse is down so we need to start a new line in mousePath
              draw = True
  
          End If
  
      End Sub
  
      Private Sub panelDraw_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles panelDraw.MouseMove
  
          If e.Button = MouseButtons.Left And (draw) Then ' draw a filled line if left mouse is down and draw is true
  
              Try
                  mousePath.AddLine(e.X, e.Y, e.X, e.Y)    'Add mouse coordiantes to mousePath
                  panelDraw.Invalidate()  ' adds new line to next update of panelDraw which will take place at the next paint event
  
              Catch
                  MsgBox("No way, Hose!")
              End Try
  
          End If
  
      End Sub
  
      Private Sub panelDraw_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles panelDraw.MouseUp
  
          ' changes draw boolean back to false   
          draw = False
  
      End Sub
  
      Private Sub panelDraw_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles panelDraw.Paint
  
          Try ' error trapping
  
              '*********************** NOTE  ***********************************************
              'The line below set the pen up with the ability to add user selected Alpha, Color and Penwidth
              ' A simpler, but less flexible solution would be to replace the line with the following code:
              'Dim CurrentPen = New Pen(System.Drawing.Color.Black, myPenWidth)
              '************  End Note  ***************************
  
              Dim CurrentPen = New Pen(userColor, penWidth) 'Set up the pen
              Dim linecap As Drawing2D.LineCap = Drawing2D.LineCap.Round
  
              CurrentPen.StartCap = linecap
  
              CurrentPen.EndCap = linecap
  
              e.Graphics.DrawPath(CurrentPen, mousePath)  'draw the path
              CurrentPen.Dispose()
  
          Catch
              ' MsgBox("Not happening!")
          End Try
  
      End Sub
  
      Public Sub ClearDrawingPanel()
  
          ' clears drawing panel
          Dim g As Graphics = panelDraw.CreateGraphics
          g.Clear(panelDraw.BackColor)
          mousePath.Reset()
          g.Dispose()
  
      End Sub
  
      Private Sub frmDrawingPad_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
  
          ' loads list of colors to combobox
          cboColorPick.Items.Add("Pick A Color")
          cboColorPick.Items.Add("Black")
          cboColorPick.Items.Add("Blue")
          cboColorPick.Items.Add("Pink")
          cboColorPick.Items.Add("Red")
          cboColorPick.Items.Add("Green")
          cboColorPick.Items.Add("Yellow")
          cboColorPick.Items.Add("Purple")
  
          ' assigns radiobuttons to array
          rbChecked(0) = rbWidth1
          rbChecked(1) = rbWidth5
          rbChecked(2) = rbWidth10
          rbChecked(3) = rbWidth20
  
      End Sub
  
      Private Sub cboColorPick_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles cboColorPick.SelectedIndexChanged
          ' assigns to index the combobox index of the selected color
          index = cboColorPick.SelectedIndex
          ' calls procedure that assigns color to pen
          Call AssignPenColor(index)
      End Sub
  
      Private Sub BlackToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BlackToolStripMenuItem.Click
          index = 1
          Call AssignPenColor(index)
      End Sub
  
      Private Sub BlueToolStripMenuItem_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles BlueToolStripMenuItem.Click
          index = 2
          Call AssignPenColor(index)
      End Sub
  
      Private Sub PinkToolStripMenuItem_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles BlueToolStripMenuItem.Click
          index = 3
          Call AssignPenColor(index)
      End Sub
  
      Private Sub RedToolStripMenuItem_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles BlueToolStripMenuItem.Click
          index = 4
          Call AssignPenColor(index)
      End Sub
  
      Private Sub GreenToolStripMenuItem_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles BlueToolStripMenuItem.Click
          index = 5
          Call AssignPenColor(index)
      End Sub
  
      Private Sub YellowToolStripMenuItem_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles BlueToolStripMenuItem.Click
          index = 6
          Call AssignPenColor(index)
      End Sub
  
      Private Sub PurpleToolStripMenuItem_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles BlueToolStripMenuItem.Click
          index = 7
          Call AssignPenColor(index)
      End Sub
  
      Private Sub AssignPenColor(ByVal index As Object)
  
          ' takes passed index collected from selection in combobox and checks to see which case it matches. once correct one is found
          ' the userColor variable is assigned the appropriate color
          Select Case index
              Case 1
                  userColor = Color.Black
              Case 2
                  userColor = Color.Blue
              Case 3
                  userColor = Color.Pink
              Case 4
                  userColor = Color.Red
              Case 5
                  userColor = Color.Green
              Case 6
                  userColor = Color.Yellow
              Case 7
                  userColor = Color.Purple
          End Select
  
      End Sub
  
      ' handles checkedchanged event for all radiobuttons
      Private Sub rbWidth1_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles rbWidth1.CheckedChanged, _
              rbWidth5.CheckedChanged, rbWidth10.CheckedChanged, rbWidth20.CheckedChanged
          penWidth = 0
          Dim i As Integer = 0
          Dim found As Boolean = False
          ' runs through loop until it finds the radiobutton which was selected within the rbChecked array
          While i < rbChecked.GetLength(0) And Not found
              If rbChecked(i).Checked Then
                  found = True
              End If
              i += 1
          End While
  
          ' once index is found it is evaluated to determine which width value should be assigned to penWidth variable
          ' an additional 1 is added to i as it leaves loop so to get accurate value we need to subtract out that added one
          Select Case i - 1
              Case 0
                  penWidth = 1.0F
              Case 1
                  penWidth = 5.0F
              Case 2
                  penWidth = 10.0F
              Case 3
                  penWidth = 20.0
          End Select
  
      End Sub
  
  End Class
   

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