text and picture problem

[aamir55]

i m writing a small program to add text on the picture box
but when i run my program...then this error comes"Object reference not set to an instance of an object." on the following line

 Dim tbm As Bitmap = CType(bm.Clone, Bitmap)

whole paint event is as follow

Private Sub PictureBox1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles PictureBox1.Paint
        Dim tbm As Bitmap = CType(bm.Clone, Bitmap)
        Dim g As Graphics = Graphics.FromImage(tbm)
        Dim mx As Matrix = New Matrix
        Dim gpathText As New GraphicsPath
        Dim br As SolidBrush = New SolidBrush(Color.FromArgb(tbarTrans.Value, _
                                              Color.LightCoral))

        'Smooth the Text
        g.SmoothingMode = SmoothingMode.AntiAlias

        'Make the GraphicsPath for the Text
        Dim emsize As Single = Me.CreateGraphics.DpiY * pic_font.SizeInPoints / 72
        'gpathText.AddString(strText, pic_font.FontFamily, CInt(pic_font.Style), _
        ' emsize, New RectangleF(ptText.X, ptText.Y, szText.Width, szText.Height), _
        ' StringFormat.GenericDefault)

        'Draw a copy of the image to the Graphics Object canvas
        g.DrawImage(CType(bm.Clone, Bitmap), 0, 0)

        'Rotate the Matrix at the center point
        mx.RotateAt(tbarRotate.Value, _
            New Point(ptText.X + (szText.Width / 2), ptText.Y + (szText.Height / 2)))

        'Get the points for the rotated text bounds
        mx.TransformPoints(ptsText)

        'Transform the Graphics Object with the Matrix
        g.Transform = mx

        'Draw the Rotated Text
        g.FillPath(br, gpathText)
        If chkAddOutline.Checked Then
            Using pn As Pen = New Pen(Color.FromArgb(tbarTrans.Value, Color.White), 1)
                g.DrawPath(pn, gpathText)
            End Using
        End If

        'Draw the box if the mouse is over the Text
        If MouseOver Then
            g.ResetTransform()
            g.DrawPolygon(ptsTextPen, ptsText)
        End If

        'Draw the whole thing to the form
        e.Graphics.DrawImage(tbm, 10, 10)

        tbm.Dispose()
        g.Dispose()
        mx.Dispose()
        br.Dispose()
        gpathText.Dispose()
    End Sub

i have converted this program from an other program which ads text on the form to a pre-assigned picture on the form
but i have converted it into a picture box
i have added a picture box and calling its paint event while in the original program..form pain event is called
attaching the file
kindly help me

[GremlinSA]

What you need here is the Graphics object, and your Bitmap must acctually be a Image type

Dim tbm As Image
Dim tbmGobj as Graphics

tbm = New Bitmap(bm.Image)
tbGobj = Graphics.FromImage (bm.Image)

Gremmy..

[aamir55]

i have tried ur code but this is giving errors
it is giving two errors on the following line

tbm = New Bitmap(bm.image)
tbmGobj = Graphics.FromImage(bm.image)

Error is "image' is not a member of 'System.Drawing.Bitmap'.
now whole code of picture paint event is as follow

Private Sub PictureBox1_Paint(ByVal sender As Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles PictureBox1.Paint

        Dim tbm As Image
        Dim tbmGobj As Graphics
        tbm = New Bitmap(bm.image)
        tbmGobj = Graphics.FromImage(bm.image)
        Dim g As Graphics = Graphics.FromImage(tbm)
        Dim mx As Matrix = New Matrix
        Dim gpathText As New GraphicsPath
        Dim br As SolidBrush = New SolidBrush(Color.FromArgb(tbarTrans.Value, _
                                              Color.LightCoral))

        'Smooth the Text
        g.SmoothingMode = SmoothingMode.AntiAlias

        'Make the GraphicsPath for the Text
        Dim emsize As Single = Me.CreateGraphics.DpiY * pic_font.SizeInPoints / 72
        'gpathText.AddString(strText, pic_font.FontFamily, CInt(pic_font.Style), _
        ' emsize, New RectangleF(ptText.X, ptText.Y, szText.Width, szText.Height), _
        ' StringFormat.GenericDefault)

        'Draw a copy of the image to the Graphics Object canvas
        g.DrawImage(CType(bm.Clone, Bitmap), 0, 0)

        'Rotate the Matrix at the center point
        mx.RotateAt(tbarRotate.Value, _
            New Point(ptText.X + (szText.Width / 2), ptText.Y + (szText.Height / 2)))

        'Get the points for the rotated text bounds
        mx.TransformPoints(ptsText)

        'Transform the Graphics Object with the Matrix
        g.Transform = mx

        'Draw the Rotated Text
        g.FillPath(br, gpathText)
        If chkAddOutline.Checked Then
            Using pn As Pen = New Pen(Color.FromArgb(tbarTrans.Value, Color.White), 1)
                g.DrawPath(pn, gpathText)
            End Using
        End If

        'Draw the box if the mouse is over the Text
        If MouseOver Then
            g.ResetTransform()
            g.DrawPolygon(ptsTextPen, ptsText)
        End If

        'Draw the whole thing to the form
        e.Graphics.DrawImage(tbm, 10, 10)

        tbm.Dispose()
        g.Dispose()
        mx.Dispose()
        br.Dispose()
        gpathText.Dispose()
    End Sub

secondly i m loading picture into the picture box through open dialog as follow

Private Sub OpenPictureToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OpenPictureToolStripMenuItem.Click
        Try
            Dim openFileDlg As New OpenFileDialog
            openFileDlg.Filter = "Images (*.BMP;*.JPG;*.GIF)|*.BMP;*.JPG;*.GIF|All files (*.*)|*.*"
            With openFileDlg
                .CheckFileExists = True
                .ShowReadOnly = False
                .Filter = "All Files|*.*|Bitmap Files (*)|*.bmp;*.gif;*.jpg"
                .FilterIndex = 2
                If .ShowDialog = Windows.Forms.DialogResult.OK Then
                    Me.PictureBox1.Image = Image.FromFile(.FileName)
                    PictureBox1.SizeMode = PictureBoxSizeMode.CenterImage
                    'If Auto_Size Then Pic2Pic(pb, Panel1, Enlarge, Shrink)
                End If
            End With
        Catch ex As Exception
            MessageBox.Show("Can not open file")
        End Try
    End Sub

i didn't understand this one"your Bitmap must acctually be a Image type"
kindly guide me more..

[javajawa]

As you've defined bm as a bitmap, this is a valid argument for both New Bitmap() and Graphics.FromImage()
Therfore:

                tbm = New Bitmap(bm)
                tbmGobj = Graphics.FromImage(bm)

Hope that Helps!

[aamir55]

i have tried this code but error is coming on the following line when i run the application

tbm = New Bitmap(bm)

what can i do now???
kindly help me.

[javajawa]

What is the error? If it mentioned a Null Reference, then the problem is that the picture bo gets painted before the variable bm is initialised. the best way round this is to declare a private variable in the form to determine whether a bitmap hads been loaded, or to perform a test on bm. For example, adding:

If bm Is Nothing Then Exit Sub

to the beginning of the paint routine should sort things out. It's not the neatest way, but the quickest to write.

[javajawa]

I've just noticed that your program fails to do anything then. In fact, as far as I can see, bm is only used as a reference point for reate other bitmaps. It is never given any dimensions, nor is it ever used directly. Therefore, it's default state is Nothing. Is it meant to represent the original image? In which case just use PictureBox1.Image.
Also, tbmGobj seems to serve no purpose either...
Well, If I'm honest, I'm a bit out of my depth in graphics...I'll stick to text and logic any day...

[aamir55]

i m giving some code here
in this code paint is applied on the form and a picture is paint on the form when program loads and a text is also loaded when first time run.
but i want make changes as following
1.i can invoke paint event of picture box
2.when program loads first time...picture box should nothing
3.i can load picture from disk through a open dialog box after loading the form
4.i can then add the text on the picture manually through a text box

Dim pic_font As New Font("Arial Black", 40, FontStyle.Regular, GraphicsUnit.Pixel)
    Dim bm As Bitmap
    Dim strText As String = "Diver Dude"
    Dim szText As New SizeF
    Dim ptText As New Point(125, 125)
    Dim ptsText() As PointF
    Dim MovingOffset As PointF
    Dim ptsTextPen As Pen = New Pen(Color.LightSteelBlue, 1)
    Dim MouseMoving As Boolean
    Dim MouseOver As Boolean

Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        bm = Image.FromFile(Application.StartupPath & "\DivePic.bmp")
        szText = Me.CreateGraphics.MeasureString(strText, pic_font)
        setptsText()
        ptsTextPen.DashStyle = DashStyle.Dot
    End Sub

Private Sub Form1_Paint(ByVal sender As Object, _
        ByVal e As System.Windows.Forms.PaintEventArgs) _
        Handles MyBase.Paint

        Dim tbm As Bitmap = CType(bm.Clone, Bitmap)
        Dim g As Graphics = Graphics.FromImage(tbm)
        Dim mx As Matrix = New Matrix
        Dim gpathText As New GraphicsPath
        Dim br As SolidBrush = New SolidBrush(Color.FromArgb(tbarTrans.Value, _
                                              Color.LightCoral))

        'Smooth the Text
        g.SmoothingMode = SmoothingMode.AntiAlias

        'Make the GraphicsPath for the Text
        Dim emsize As Single = Me.CreateGraphics.DpiY * pic_font.SizeInPoints / 72
        gpathText.AddString(strText, pic_font.FontFamily, CInt(pic_font.Style), _
            emsize, New RectangleF(ptText.X, ptText.Y, szText.Width, szText.Height), _
            StringFormat.GenericDefault)

        'Draw a copy of the image to the Graphics Object canvas
        g.DrawImage(CType(bm.Clone, Bitmap), 0, 0)

        'Rotate the Matrix at the center point
        mx.RotateAt(tbarRotate.Value, _
            New Point(ptText.X + (szText.Width / 2), ptText.Y + (szText.Height / 2)))

        'Get the points for the rotated text bounds
        mx.TransformPoints(ptsText)

        'Transform the Graphics Object with the Matrix
        g.Transform = mx

        'Draw the Rotated Text
        g.FillPath(br, gpathText)
        If chkAddOutline.Checked Then
            Using pn As Pen = New Pen(Color.FromArgb(tbarTrans.Value, Color.White), 1)
                g.DrawPath(pn, gpathText)
            End Using
        End If

        'Draw the box if the mouse is over the Text
        If MouseOver Then
            g.ResetTransform()
            g.DrawPolygon(ptsTextPen, ptsText)
        End If

        'Draw the whole thing to the form
        e.Graphics.DrawImage(tbm, 10, 10)

        tbm.Dispose()
        g.Dispose()
        mx.Dispose()
        br.Dispose()
        gpathText.Dispose()
    End Sub

then help me...thanks