Saving a drawn signature as a bitmap

[steve_rm]

Hello,

VS 2005 CF 2.0

I have created a PDA device and will allow the user to write there signature.

However, I am having problems with the saving part.

http://msdn2.microsoft.com/en-us/library/aa446559.aspx

I used the above as a example, and took out all the code I needed to draw the signature and the new button.

I need to save the signature and add it to the database as an image. I think I need to convert the signature to an bitmap, but not sure how to do this.

Many thanks for any help and advice,

Steve

[steve_rm]

Hello,

I am still confused about a few things.

Firstly my code for saving the signature that has been captured on the picturebox1.

Code SnippetPrivate Sub butSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles butSave.Click
 
Try
 
Dim bmp As New Bitmap(Me.PictureBox1.Image)
 
Using g As Graphics = Graphics.FromImage(bmp)
 
Using pen As Pen = New Pen(Color.Red, 2)
 
For Each pointList As List(Of Point) In strokeCollection
 
If (pointList.Count >= 2) Then
 
g.DrawLines(pen, pointList.ToArray())
 
End If
 
Next pointList
 
End Using
 
End Using
 
Catch ex As Exception
 
MsgBox(ex.Message)
 
End Try
 
End Sub

Here I get an error message on this line: Dim bmp As New Bitmap(Me.PictureBox1.Image). 'The picture.Image is NULL'

My understanding that the picturebox1.Image should be the signature that has been captured on the pictureBox1. And as this has been drawn over, it shouldn't really be null but contain the signature itself. Correct me if I am wrong?

Many thanks for your help.

The rest of the code for my program is below if you need to review.

Code Snippet 
 
#Region "Local Variables"
 
Private lastPoint As Point
 
Private strokeCollection As New List(Of List(Of Point))
 
Private currentStroke As New List(Of Point)
 
#End Region
 
#Region "Constructor"
 
Public Sub New()
 
InitializeComponent()
 
AddHandler PictureBox1.Paint, AddressOf PictureBox1_Paint
 
End Sub
 
#End Region
 
#Region "PictureBox1_Paint Event"
 
Private Sub PictureBox1_Paint(ByVal sender As System.Object, ByVal e As PaintEventArgs)
 
For Each pointList As List(Of Point) In strokeCollection
 
If pointList.Count >= 2 Then
 
Using pen As New Pen(Color.Black, 2)
 
e.Graphics.DrawLines(pen, pointList.ToArray())
 
End Using
 
End If
 
Next
 
End Sub
 
#End Region
 
#Region "Picture box mouse down event"
 
Private Sub PictureBox1_MouseDown(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseDown
 
Try
 
Me.lastPoint = New Point(e.X, e.Y)
 
Me.currentStroke = New List(Of Point)
 
Me.strokeCollection.Add(Me.currentStroke)
 
Catch ex As Exception
 
MsgBox(ex.Message)
 
End Try
 
End Sub
 
#End Region
 
#Region "Picture box mouse move event"
 
Private Sub PictureBox1_MouseMove(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseMove
 
Dim hDC As IntPtr = GetDC(Me.PictureBox1.Handle)
 
Using g As Graphics = Graphics.FromHdc(hDC)
 
Using pen As Pen = New Pen(Color.Black, 2)
 
g.DrawLine(pen, lastPoint.X, lastPoint.Y, e.X, e.Y)
 
End Using
 
End Using
 
ReleaseDC(Me.PictureBox1.Handle, hDC)
 
Me.lastPoint = New Point(e.X, e.Y)
 
Me.currentStroke.Add(Me.lastPoint)
 
End Sub
 
#End Region
 
#Region "Attributes"
 
<System.Runtime.InteropServices.DllImport("coredll.dll")> _
 
Private Shared Function GetDC(ByVal hWnd As IntPtr) As IntPtr
 
End Function
 
<System.Runtime.InteropServices.DllImport("coredll.dll")> _
 
Private Shared Function ReleaseDC(ByVal hWnd As IntPtr, ByVal hDC As IntPtr) As Integer
 
End Function
 
#End Region

[petevick]

Hi,
this sample (http://www.codeproject.com/netcf/Sig...apture_PPC.asp) does what you need, but in c# - you could always use a translator

There are some questions/notes on the sample you used here

[steve_rm]

Hello Petevick,

Thanks for your reply. However, I would like to get the one that I have already done finished. As I still have a problem with it. I don't really want to start something new, as there is more to learn of what I am doing wrong with my current problem.

Anyway I have got further now. I have inserted a picture into the image property of the pictureBox1. So don't get the error message like i did in post #2.

The Error message I am getting now is on the bmp.Save(signaturePath, ImageFormat.Png) "NotSupportedException"

My code as below:

Private Sub butSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles butSave.Click
        Try
            Dim bmp As New Bitmap(Me.PictureBox1.Image)
 
            Dim signaturePath As String = IO.Path.GetDirectoryName(Reflection.Assembly.GetExecutingAssembly.GetName.CodeBase)
            signaturePath = IO.Path.Combine(signaturePath, "signature.png")
 
            Using g As Graphics = Graphics.FromImage(bmp)
                Using pen As Pen = New Pen(Color.Red, 2)
                    For Each pointList As List(Of Point) In strokeCollection
                        If (pointList.Count >= 2) Then
                            g.DrawLines(pen, pointList.ToArray())
                        End If
                    Next pointList
                End Using
            End Using
            bmp.Save(signaturePath, ImageFormat.Png)
 
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
    End Sub

Many Many thanks if you could help me more with this problem.

Steve

[petevick]

Hi,
did you check whether the questions/notes helped with your issue?

[steve_rm]

hello,

Thanks for the reply. Yes I did look through the website and downloaded the sample project. But that project is very complicated for me to understand.

I was using the following from the question/notes but of no help.

bmp.Save(signaturePath, ImageFormat.Png)
            Me.PictureBox1.Image.Save(signaturePath, ImageFormat.Png)

Help would be most grateful if you could further explain,

Many thanks,

[sandra05]

yeah, what's the further explain

[petevick]

Hi,
what platform are you running on - PPC 2003, WM5 or WM6?

Try changing if to saving as a .bmp using imageformat.bmp

You would get an unsupported exception if you tried to save as a .png in PPC2003

Pete

[steve_rm]

Hi Petevick,

Thank for the reply. Yes I am using Windows Mobile 5.

I will check this later.

Thanks,

Steve