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Barcode 3 of 9 generator


Create a 3 of 9 bar code without using a TTF, DLL or OCX.

Original Author: Fernando Sola

Inputs

A String (sToCode) with the data you want to use for the bar code.
'A PictureBox (pPaintInto) object where the code will draw the bar code.
'A Label (pLabelInto) object where the code will put the human readable data.

Assumptions

You should have a Label control and a PictureBox control in your Form before running this code. This controls will be passed as parameters to the Sub.
'Example: Code3of9 "123-ABC", Picture1, Label1
'I see bar codes as a binary graphic since each "bar coded" character has a 16 pixels fixed width. Actually the standard says that the codes have 9 positions from which 3 of them are wide. Each position is either a bar or a space and between each character there is a narrow space. I added the space as part of the character.
'The sValidCodes string has all the valid characters bar codes coded into decimal numbers so every character uses 5 digits from the string. For example, the "*" character uses the last 5 digits from the string (35770) which would be:
'1000101110111010 in a binary way. Whenever there is a one, this code will draw a line in the propper position of the PictureBox control.
'I created this code to print the bar code that a friend uses in his frequent customer cards. He used to print them with several True Type Fonts and he was having a lot of trouble reading them with a (very) cheap bar code scanner. I developped this code originally for Excel but it has been changed to work perfectly in Visual Basic.
'If any one of you can test it in earlier versions of VB (4 or earlier) I would really appreciate your comments about how it works (if it works of course).
'And at the end but not less important please let me know what you think about it with your comments and/or score. I really appreciate that to know how I am doing with my development skills/knowledge.

Returns

Nothing

Code

Public Sub Code3of9(sToCode As String, pPaintInto As PictureBox, pLabelInto As Label)

Dim sValidChars As String
Dim sValidCodes As String
Dim lElevate As Integer
Dim lCounter As Long
Dim lWkValue As Long
Dim PosX As Long
Dim PosY1 As Long
Dim PosY2 As Long
Dim TPX As Long

pPaintInto.Cls

TPX = Screen.TwipsPerPixelX

sValidChars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ-. $/+%*"
sValidCodes = "41914595664727860970419025962647338417105957" + _
"84729059950476626106644590602984801043246599" + _
"62476744460260046477586109044686603224803443" + _
"91860130478424477058030365265828235758580903" + _
"65863556658042365383495434978353624150635770"

sToCode = UCase(IIf(Left(sToCode, 1) = "*", "", "*") + sToCode + IIf(Right(sToCode, 1) = "*", "", "*"))
PosX = ((((pPaintInto.Width / TPX) - (Len(sToCode) * 16)) / 2) * TPX) - 1
PosY1 = pPaintInto.Height * 0.2
PosY2 = pPaintInto.Height * 0.8

If PosX < 0 Then
MsgBox "The length of the code exceeds control limits.", vbExclamation, "Large string"
GoTo End_Code
End If

On Error Resume Next

For lCounter = 1 To Len(sToCode)
'Here is where the number is fetched from the sValidCodes string. It will get only 5 digits.
lWkValue = Val(Mid(sValidCodes, ((InStr(1, sValidChars, Mid(sToCode, lCounter, 1)) - 1) * 5) + 1, 5))
lWkValue = IIf(lWkValue = 0, 36538, lWkValue)
For lElevate = 15 To 0 Step -1
'It evaluates the binary number to see if it has to draw a line.
If lWkValue >= 2 ^ lElevate Then
pPaintInto.Line (PosX, PosY1)-(PosX, PosY2)
lWkValue = lWkValue - (2 ^ lElevate)
End If
PosX = PosX + TPX
Next
Next
pLabelInto.Caption = Mid(sToCode, 2, Len(sToCode) - 2)
End_Code:
End Sub

About this post

Posted: 2002-06-01
By: ArchiveBot
Viewed: 102 times

Categories

Visual Basic 6

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