Create Image from Panel Control

gwittlock

I thought I seen an example up here before But I will be dang if I can find it now. I have a panel control which has geometry created on it from a third party dll. What I would like to do is that and create an image (preferably with transparent background) of what the user is seeing on that screen. can anyone point me in the right direction? Oh I guess I should mention that I am using VS2013 vb.net Thanks

Lost User

A panel is a control, and those can be drawn to a bitmap. See MSDN[^] :)

Bastard Programmer from Hell :suss: If you can't read my code, try converting it here[^]

gwittlock

Thanks for the advice but that does not create a transparent bitmap and in most cases will not work if the actual drawing to the panel is done through a 3rd party dll. I think what I really need is more of a screen capture of the panel and then convert its size and transparentcy

gwittlock

I found this bit of code to work with 2 exceptions. 1) how to re-size it to a smaller image (So I can display a thumbnail type image and 2) how to make the background transparent. I want item 2 because the image is displayed in a panel control with a black background. That is what the user needs to see. But when I create the image I do not want the black background

Private Sub my_capture(ctrl As Control, fileName As String)
Dim bounds As Rectangle = ctrl.Bounds
Dim pt As Point = ctrl.PointToScreen(bounds.Location)
Dim bitmap As New Bitmap(bounds.Width, bounds.Height)
Using g As Graphics = Graphics.FromImage(bitmap)
g.CopyFromScreen(New Point(pt.X - ctrl.Location.X, pt.Y - ctrl.Location.Y), Point.Empty, bounds.Size)
End Using

    bitmap.Save(fileName, ImageFormat.Png)
End Sub

Lost User

You'd have to specify which color should become transparent[^].

Bastard Programmer from Hell :suss: If you can't read my code, try converting it here[^]

gwittlock

I changed my code to this: But it had no effect. I still get the image with a black background. I am not sure how to include images with the reply otherwise I would show you before and after images

Dim bounds As Rectangle = ctrl.Bounds
Dim pt As Point = ctrl.PointToScreen(bounds.Location)
Dim myBitmap As New Bitmap(bounds.Width, bounds.Height)

    myBitmap.MakeTransparent(ctrl.BackColor)

    Using m\_g As Graphics = Graphics.FromImage(myBitmap)
        m\_g.CopyFromScreen(New Point(pt.X - ctrl.Location.X, pt.Y - ctrl.Location.Y), Point.Empty, bounds.Size)
        m\_g.Dispose()
    End Using

    myBitmap.Save(fileName, ImageFormat.Png)
    myBitmap.Dispose()

drago11

Hi Imports System.Drawing.Imaging Imports System.Drawing.Printing Private Sub PrintDocument1_PrintPage(ByVal Sender As Object, ByVal e As System.Drawing.Printing.PrintPageEventArgs) Handles PrintDocument1.PrintPage Static page As Integer = 1 Dim startPosition As Integer = (page - 1) * PrintDocument1.DefaultPageSettings.Bounds.Height Static maxPages As Integer = 0 If page = 1 Then For Each ctrl As Control In Me.pRight19.Controls If TypeOf ctrl Is TextBox Or TypeOf ctrl Is Label Or TypeOf ctrl Is PictureBox Or TypeOf ctrl Is RichTextBox Then ctrl.Tag = Int((ctrl.Top + ctrl.Height) / PrintDocument1.DefaultPageSettings.Bounds.Height) + 1 If CInt(ctrl.Tag) > maxPages Then maxPages = CInt(ctrl.Tag) End If Next End If For Each ctrl As Control In Me.pRight19.Controls If CInt(ctrl.Tag) = page Then If TypeOf ctrl Is TextBox Or TypeOf ctrl Is Label Or TypeOf ctrl Is RichTextBox Then Dim sf As New System.Drawing.StringFormat If TypeOf ctrl Is TextBox Then If DirectCast(ctrl, TextBox).TextAlign = HorizontalAlignment.Right Then sf.Alignment = StringAlignment.Far Else sf.Alignment = StringAlignment.Near End If ElseIf TypeOf ctrl Is Label Then If DirectCast(ctrl, Label).TextAlign = ContentAlignment.TopLeft Then sf.Alignment = StringAlignment.Far End If ElseIf TypeOf ctrl Is RichTextBox Then If DirectCast(ctrl, RichTextBox).SelectionAlignment = ContentAlignment.TopLeft Then sf.Alignment = StringAlignment.Near End If End If sf.FormatFlags = StringFormatFlags.NoClip e.Graphics.DrawString(ctrl.Text, ctrl.Font, New SolidBrush(ctrl.ForeColor), New Rectangle(ctrl.Left, ctrl.Top - startPosition, ctrl.Width + 50, ctrl.Height), sf) ElseIf TypeOf ctrl Is PictureBox Then e.Graphics.DrawImage(DirectCast(ctrl, PictureBox).Image, New PointF(ctrl.Left, ctrl.Top - startPosition)) End If End If Next page += 1

Lost User

Set the transparency AFTER you capture the screen.

Bastard Programmer from Hell :suss: If you can't read my code, try converting it here[^]

gwittlock

Eddy yep that is what the issue was. Setting it after did the trick. Now that I have that working(thanks to you) and I see the results, I think I need to save the image as B/W or greyScale. Is that difficult?

gwittlock

Drago11 I am not sure what all the printing code has to do with my question. Maybe you just pasted it in to the wrong question. Am I missing something?

Lost User

Not very hard, but I reckon it will need to remain a 32bit argb format for transparency to work. There's a howto[^] on MSDN :)

Bastard Programmer from Hell :suss: If you can't read my code, try converting it here[^]

Lost User

That's the good answer, but to the wrong question :laugh:

Bastard Programmer from Hell :suss: If you can't read my code, try converting it here[^]

gwittlock

Hmmm that use the Imaging class I have seen that used in medical applications I believe, Maybe I will try a different approach. You would think that Microsoft would of made saving an image a whole lot easier wouln't you? :laugh:

gwittlock

I am using the this sub and on the following line of code I get an error

pixColor = myBitmap.GetPixel(x, y)

the error states "An unhandled exception of type 'System.ArgumentOutOfRangeException' occurred in System.Drawing.dll Additional information: Parameter must be positive and < Width." Would anyone know why?

Private Sub my_capture(ctrl As Control, fileName As String)
Dim bounds As Rectangle = ctrl.Bounds
Dim pt As Point = ctrl.PointToScreen(bounds.Location)
Dim myBitmap As New Bitmap(bounds.Width, bounds.Height)
Dim BW_Bitmap As New Bitmap(bounds.Width, bounds.Height)
Dim x As Integer
Dim y As Integer
Dim pixColor As Color
Dim luma As Integer

    Using m\_g As Graphics = Graphics.FromImage(myBitmap)

        m\_g.CopyFromScreen(New Point(pt.X - ctrl.Location.X, pt.Y - ctrl.Location.Y), Point.Empty, bounds.Size)

        m\_g.Dispose()

    End Using

    For y = 0 To BW\_Bitmap.Height

        For x = 0 To BW\_Bitmap.Width

            pixColor = myBitmap.GetPixel(x, y)

            luma = CInt(pixColor.R \* 0.3 + pixColor.G \* 0.59 + pixColor.B \* 0.11)

            BW\_Bitmap.SetPixel(x, y, Color.FromArgb(luma, luma, luma))

        Next

    Next

    BW\_Bitmap.Save(fileName, ImageFormat.Png)

    BW\_Bitmap.Dispose()

    myBitmap.Dispose()

End Sub

Lost User

..from 0 to 640, is 641 steps, not 640. That's one more step than there is pixels, causing it to go out of range.

Bastard Programmer from Hell :suss: If you can't read my code, try converting it here[^]

gwittlock

Well :doh: ! Boy do I feel stupid. Thanks