Problem changing color and width in drawing program

  • 10 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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