[vb2005] Print/Preview a form or a control

[ZaNi]

Preamble:
I needed to print a form with a mass of different controls on it, one in particular was a picturebox which had a complex graphic drawn on it. I looked for help on printing, and though I found a fair amount, I couldn't solve my problem. Through a combination of perservence, searching, and the reading of many many Intellisense prototypes, I found a way to print from a screenshot. This is not a perfect solution, but if you have a form or control that you need printed and an easy way to do it, I have written something you may be able to use.

Feel free to post any problems, corrections, or comments

Limitations of this code:
As this code takes a screenshot, the object you are printing (eg the form you want to print) must be on top of all others. Otherwise, you will end up with a screenshot of something you didn't intend.

Details:
Note: Currently the control printing and previewing is not working. I will try and fix this later, but just ignore it for now (or fix it if you want)

Below is a module that can be added to any vb.net 2005 project to allow for easy printing (and print previews) of three things: A form, a form's client area, and a control. There are six (6) public routines at your disposal to print what you need quickly. Also, the code should help anybody who ran into the problem of not knowing how to print or where to begin searching.

I will provide a list of information sources I used to write this after the module:

Module PrintObject
 
    Dim screenshot As Bitmap
 
    Public Sub PrintControl(ByRef sender As Control)
        GetScreenshotOfControl(sender)
        PrepareAndPrint()
    End Sub
 
    Public Sub PrintPreviewControl(ByRef sender As Control)
        GetScreenshotOfControl(sender)
        PrepareAndPrintPreview()
    End Sub
 
    Public Sub PrintForm(ByRef myform As Windows.Forms.Form)
        GetScreenShotOfForm(myform)
        PrepareAndPrint()
    End Sub
 
    Public Sub PrintPreviewForm(ByRef myform As Windows.Forms.Form)
        GetScreenShotOfForm(myform)
        PrepareAndPrintPreview()
    End Sub
 
    Public Sub PrintFormClientArea(ByRef myform As Windows.Forms.Form)
        GetScreenShotOfFormClientArea(myform)
        PrepareAndPrint()
    End Sub
 
    Public Sub PrintPreviewFormClientArea(ByRef myform As Windows.Forms.Form)
        GetScreenShotOfFormClientArea(myform)
        PrepareAndPrintPreview()
    End Sub
 
 
    ' Remaining routines are helper routines to perform tasks assigned by public routines
 
 
    Private Sub GetScreenshotOfControl(ByRef sender As Control)
        ' First get the local coordinates of the control
        Dim mylocalsize As Rectangle = New Rectangle(sender.Location, sender.Size)
        ' Now get the global coordinates of the control
        Dim mysize As Rectangle = sender.RectangleToScreen(mylocalsize)
        screenshot = New Bitmap(mysize.Width, mysize.Height)
        Dim g As Graphics = Graphics.FromImage(screenshot)
        Dim pt As Point = New Point(0, 0)
        ' myloc is the top-left of the client area of the form in global co-ordinates
        Dim myloc As Point = New Point(mysize.Location.X, mysize.Location.Y)
        g.CopyFromScreen(myloc, pt, mysize.Size)
    End Sub
 
    Private Sub GetScreenshotOfForm(ByRef myform As Windows.Forms.Form)
        Dim mysize As Rectangle = New Rectangle(myform.Location, myform.Size)
        screenshot = New Bitmap(mysize.Width, mysize.Height)
        Dim g As Graphics = Graphics.FromImage(screenshot)
        Dim pt As Point = New Point(0, 0)
        ' myloc is the top-left of the client area of the form in global co-ordinates
        Dim myloc As Point = New Point(mysize.Location.X, mysize.Location.Y)
        g.CopyFromScreen(myloc, pt, mysize.Size)
    End Sub
 
    Private Sub GetScreenshotOfFormClientArea(ByRef myform As Windows.Forms.Form)
        Dim mysize As Rectangle = myform.ClientRectangle
        screenshot = New Bitmap(mysize.Width, mysize.Height)
        Dim g As Graphics = Graphics.FromImage(screenshot)
        Dim pt As Point = New Point(0, 0)
        ' myloc is the top-left of the client area of the form in global co-ordinates
        Dim myloc As Point = New Point(mysize.Location.X + myform.Location.X, _
        mysize.Location.Y + myform.Location.Y + (myform.Height - mysize.Height))
        g.CopyFromScreen(myloc, pt, mysize.Size)
    End Sub
 
    Private Sub PrepareAndPrint()
        ' This is a standard print function with a save dialog
        '   added if the user chooses to print to a file
        Dim doc As Printing.PrintDocument = New Printing.PrintDocument
        Dim printer As PrintDialog = New PrintDialog
        AddHandler doc.PrintPage, AddressOf PrintPageHandler
        printer.Document = doc
        Dim response As Windows.Forms.DialogResult = printer.ShowDialog()
        If response = Windows.Forms.DialogResult.OK Then
            If doc.PrinterSettings.PrintToFile = True Then
                ' Allow the user to set the filename using a dialog
                Dim save As New SaveFileDialog()
                save.Filter = "Plain Text Files (*.txt)|*.txt|All Files (*.*)|*.*"
                save.CheckPathExists = True
                save.Title = "Spool printer output"
                If save.ShowDialog() = Windows.Forms.DialogResult.OK Then
                    doc.PrinterSettings.PrintFileName = save.FileName
                Else
                    ' User must not want to print if they cancelled
                    Exit Sub
                End If
            End If
            doc.Print()
        End If
    End Sub
 
    Private Sub PrepareAndPrintPreview()
        Dim doc As Printing.PrintDocument = New Printing.PrintDocument
        Dim printer As PrintPreviewDialog = New PrintPreviewDialog
        AddHandler doc.PrintPage, AddressOf PrintPageHandler
        printer.Document = doc
        printer.ShowDialog()
    End Sub
 
    Private Sub PrintPageHandler(ByVal sender As Object, _
    ByVal e As System.Drawing.Printing.PrintPageEventArgs)
        Dim canvas As Graphics = e.Graphics
        ' The printer will print the image to whatever bounds are set here (in the next two lines)
        Dim topLeft As Point = New Point(0, 0)
        Dim bottomRight As Point = New Point(e.PageBounds.Width, e.PageBounds.Height)
        ' The rest of the code should not need to be modified
        ' This algorithm makes sure the image scales properly
        Dim pageHeight As Integer = bottomRight.Y - topLeft.Y
        Dim pageWidth As Integer = bottomRight.X - topLeft.X
        Dim scaleHeight As Single = pageHeight / screenshot.Height
        Dim scaleWidth As Single = pageWidth / screenshot.Width
        ' NewHeight and NewWidth determine the drawing area.
        ' Assume scaleHeight < scaleWidth
        Dim newHeight As Integer = scaleHeight * screenshot.Height
        Dim newWidth As Integer = scaleHeight * screenshot.Width
        ' Now check assumption, and correct if wrong
        If scaleWidth < scaleHeight Then
            newHeight = scaleWidth * screenshot.Height
            newWidth = scaleWidth * screenshot.Width
        End If
        canvas.DrawImage(screenshot, topLeft.X, topLeft.Y, newWidth, newHeight)
    End Sub
 
End Module

Resources:
Article on printing in vb.net 2003 (My main resource)
Another such module for printing (Part of the inspiration for this)
Some printing fundamentals from jmcilhinney
Another codeback submission that helps with printing text documents (I didn't use it, but it might be helpful)