Printing with formatting in VB.NET

I have searched all over the web for good printing code and was unable to find it.  I have created a printing class which allows text to be formatted at the character level.  It has taken me about a week to get what I have working correctly and I thought it would be nice to save others the time.

My code is easily modified and shouldn’t be too hard to understand.  It is well commented.  It recognizes the HTML bold tag and a special <ST=> tag which I created to take the place of what tables do in HTML.  Paragraphs are separated using vbCrLf and lines will wrap correctly without chopping off a word.

Here is the block of code to instantiate and use the class:

' Create object, passing in text
Dim MyPrintObject As New TextPrint("<B>this will be bold</B>" + _
vbCrLf + "<ST=400>this will start at 400 pixels")
' Set font, defaults to times new roman, 12 if omitted
MyPrintObject.Font = New Font("Tahoma", 8)
' Issue print command
MyPrintObject.Print()

Here is the actual printing class which does the work:

Public Class TextPrint
' Inherits all the functionality of a PrintDocument
Inherits Printing.PrintDocument
' Private variables to hold default font and text
Private fntPrintFont As Font
Private strText As String
Dim MySplitLine As String()
Dim varStart As Integer = 0
Dim varChar As Integer = 0
' New constructor
Public Sub New(ByVal Text As String)
' Sets the file stream
MyBase.New()
varStart = 0
strText = Text
MySplitLine = strText.Split(vbCrLf)
End Sub
Public Property Text() As String
Get
Return strText
End Get
Set(ByVal Value As String)
strText = Value
MySplitLine = strText.Split(vbCrLf)
End Set
End Property
Protected Overrides Sub OnBeginPrint(ByVal ev As Printing.PrintEventArgs)
' Run base code
MyBase.OnBeginPrint(ev)
' Sets the default font
If fntPrintFont Is Nothing Then
fntPrintFont = New Font("Times New Roman", 12, FontStyle.Regular, GraphicsUnit.Point)
End If
End Sub
Public Property Font() As Font
' Allows the user to override the default font
Get
Return fntPrintFont
End Get
Set(ByVal Value As Font)
fntPrintFont = Value
End Set
End Property

Protected Overrides Sub OnPrintPage(ByVal e As Printing.PrintPageEventArgs)
' Provides the print logic for our document

' Run base code
MyBase.OnPrintPage(e)

' Draw the margins (for debugging).
'e.Graphics.DrawRectangle(Pens.Red, e.MarginBounds)

Dim the_font As Font = fntPrintFont
Dim string_format As New StringFormat

' Draw the text left justified,
' wrap at words, and don't draw partial lines.
string_format.Alignment = StringAlignment.Near
string_format.FormatFlags = StringFormatFlags.LineLimit
string_format.Trimming = StringTrimming.Word

' Draw some text.
Dim ymin As Integer = e.MarginBounds.Top
Dim layout_rect As RectangleF
Dim text_size As SizeF
Dim characters_fitted As Integer
Dim lines_filled As Integer

Static i As Integer
For i = varStart To MySplitLine.GetUpperBound(0)
' get ready for the 1 char printing
Dim smallArray As String(,)
Dim xmin As Integer = e.MarginBounds.Left
Dim varWord As RectangleF()
ReDim varWord(1)
Dim wordCountForLine As Integer = 0
' make sure a space prints if a two vbcrlf's are in a row
If Trim(Len(MySplitLine(i))) = 1 Then
ReDim smallArray(3, 1)
smallArray(0, 0) = ""
smallArray(1, 0) = FontStyle.Regular
smallArray(2, 0) = -1
ymin += CInt(the_font.Height)
Else
'***Special print 1 char at a time for formatting***
smallArray = checkBold(Trim(MySplitLine(i).ToString), fntPrintFont)
'***END print 1 char at a time for formatting***
End If
Dim x As Integer
For x = varChar To smallArray.GetUpperBound(1) - 1
'remove blanks so ascii works
If smallArray(0, x).Length = 0 Then smallArray(0, x) = Chr(0)
' Get the font for measurement.
the_font = New Font(fntPrintFont.Name, fntPrintFont.Size, _
 CInt(smallArray(1, x)), fntPrintFont.Unit)
' Set the text start location if desired
If CInt(smallArray(2, x)) > -1 Then xmin = CInt(smallArray(2, x))
' Get the area available for this text.
layout_rect = New RectangleF(xmin, ymin, e.MarginBounds.Right - xmin, the_font.Height)
' If the layout rectangle's height < 1, make it 1.
If layout_rect.Height < 1 Then layout_rect.Height = 1
' See how big the text will be and
' how many characters will fit.
text_size = e.Graphics.MeasureString(smallArray(0, x).ToString, the_font, _
New SizeF(layout_rect.Width, layout_rect.Height), _
string_format, characters_fitted, lines_filled)

' See if any characters will fit.
If characters_fitted > 0 Then
' start accumulating the print location
varWord(varWord.GetUpperBound(0) - 1) = layout_rect

' ************Draw the word when finished.************
If Asc(smallArray(0, x).Chars(0)) = 32 Or x = smallArray.GetUpperBound(1) - 1 Then
Dim z As Integer
For z = x - (varWord.GetUpperBound(0) - 1) To x
' Get the font for measurement.
the_font = New Font(fntPrintFont.Name, fntPrintFont.Size, _
CInt(smallArray(1, z)), fntPrintFont.Unit)
' actually print the character on the page.
e.Graphics.DrawString(smallArray(0, z), _
the_font, Brushes.Black, _
varWord((z - x) + (varWord.GetUpperBound(0) - 1)), string_format)
Next
xmin += 4
ReDim varWord(0)
wordCountForLine += 1
End If

'' Draw a rectangle around the text (for debugging).
'e.Graphics.DrawRectangle(Pens.Green, _
' layout_rect.Left, _
' layout_rect.Top, _
' text_size.Width, _
' text_size.Height)

' Increase the location where we can start.
xmin += CInt(text_size.Width) - 4
ReDim Preserve varWord(varWord.GetUpperBound(0) + 1)
ElseIf Asc(smallArray(0, x).Chars(0)) < 30 Then
' make sure to dispose of odd char's in the array
Else ' See if some of the paragraph didn't fit
' ********Draw the word if longer than one line.**********
If wordCountForLine = 0 Then
varWord(varWord.GetUpperBound(0) - 1) = layout_rect
Dim z As Integer
For z = x - (varWord.GetUpperBound(0) - 1) To x
e.Graphics.DrawString(smallArray(0, z), _
the_font, Brushes.Black, _
varWord((z - x) + (varWord.GetUpperBound(0) - 1)), string_format)
Next
ReDim varWord(0)
End If

'*******reset the variables*********
wordCountForLine = 0
x -= varWord.GetUpperBound(0)
ReDim varWord(1)
xmin = e.MarginBounds.Left
ymin += CInt(the_font.Height) ' move to the next line
'see if there are more lines available
If (e.MarginBounds.Bottom - ymin) < the_font.Height Then
Exit For ' exit for loop so page can print
End If
End If
Next
ymin += CInt(the_font.Height) ' move to the next line
If (e.MarginBounds.Bottom - ymin) < the_font.Height Then
varChar = x 'save character location
varStart = i 'save line location
e.HasMorePages = True 'after printing page, run sub again
Exit For ' exit for loop so page can print
Else
varChar = 0
e.HasMorePages = False
End If
Next
End Sub
Private Function checkBold(ByVal varString As String, ByVal startFont As Font) As String(,)
Dim aryString As String(,)
ReDim aryString(3, 1)
Dim printStyle As FontStyle = FontStyle.Regular
Dim varStartPlace As Integer = -1

aryString(0, 0) = "" 'initialize the array to avoid errors
aryString(1, 0) = printStyle
aryString(2, 0) = varStartPlace

Dim varPlace As Integer = 0
For varPlace = 1 To varString.Length
If Mid(varString, varPlace, 3) = "<B>" Then
printStyle = FontStyle.Bold
varPlace += 2
ElseIf Mid(varString, varPlace, 4) = "</B>" Then
printStyle = FontStyle.Regular
varPlace += 3
ElseIf Mid(varString, varPlace, 4) = "<ST=" Then
varStartPlace = CInt(Mid(varString, varPlace + 4, _
InStr(varPlace + 4, varString, ">") - (varPlace + 4)))
varPlace += 4 + varStartPlace.ToString.Length
Else
ReDim Preserve (aryString(3, aryString.GetUpperBound(1) + 1))
aryString(0, aryString.GetUpperBound(1) - 1) = Mid(varString, varPlace, 1)
aryString(1, aryString.GetUpperBound(1) - 1) = printStyle
aryString(2, aryString.GetUpperBound(1) - 1) = varStartPlace
varStartPlace = -1
End If
Next
checkBold = aryString

End Function

End Class

Obviously there are many enhancements which can be done to it; however it should be a great start for most programmers.

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Comments

Jereme Guenther

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