Qr Code In Vb6

' Basic QR code generator for simple text
Private Sub GenerateSimpleQRCode(ByVal Text As String, ByVal Scale As Integer)
    Dim QRMatrix(20, 20) As Boolean ' Simple 20x20 grid
    Dim i As Integer, j As Integer
' Fill with position markers (simplified)
For i = 0 To 6
    For j = 0 To 6
        If i = 0 Or i = 6 Or j = 0 Or j = 6 Or _
           (i >= 2 And i <= 4 And j >= 2 And j <= 4) Then
            QRMatrix(i, j) = True
        End If
    Next j
Next i
' Add text data (simplified binary representation)
Dim TextBytes() As Byte
TextBytes = StrConv(Text, vbFromUnicode)
Dim bitPos As Integer
bitPos = 0
For i = 8 To 20
    For j = 8 To 20
        If bitPos < UBound(TextBytes) * 8 Then
            ' Set bit based on byte data
            QRMatrix(i, j) = (TextBytes(bitPos \ 8) And (2 ^ (7 - (bitPos Mod 8)))) <> 0
            bitPos = bitPos + 1
        End If
    Next j
Next i
' Draw QR code
DrawQRMatrix QRMatrix, Scale

End Sub
Private Sub DrawQRMatrix(ByRef Matrix() As Boolean, ByVal Scale As Integer)
Dim x As Integer, y As Integer
Dim width As Integer, height As Integer
width = UBound(Matrix, 1) + 1
height = UBound(Matrix, 2) + 1
' Create picture box with appropriate size
Picture1.Width = (width * Scale) * 15 ' Convert to twips
Picture1.Height = (height * Scale) * 15
Picture1.ScaleMode = vbPixels
Picture1.Width = width * Scale
Picture1.Height = height * Scale
' Draw QR code
For x = 0 To width - 1
    For y = 0 To height - 1
        If Matrix(x, y) Then
            Picture1.Line (x * Scale, y * Scale)-Step(Scale, Scale), vbBlack, BF
        Else
            Picture1.Line (x * Scale, y * Scale)-Step(Scale, Scale), vbWhite, BF
        End If
    Next y
Next x

End Sub

Imagine a VB6 inventory app that prints QR labels for bins.

Private Sub PrintQRLabel(ByVal partNumber As String, ByVal location As String)
    Dim qrText As String
    Dim qrImage As StdPicture
    qrText = "PN:" & partNumber & "|LOC:" & location
' Generate QR via DLL
Dim qrGen As New QRCodeGen.QuickResponse
Set qrImage = qrGen.CreateQR(qrText, 200) ' 200px
' Print using VB6 Printer object
Printer.ScaleMode = vbTwips
Printer.PaintPicture qrImage, 500, 500, 4000, 4000
Printer.CurrentX = 500
Printer.CurrentY = 4500
Printer.Print "Part: " & partNumber
Printer.Print "Loc: " & location
Printer.EndDoc

End Sub

That night, Martin faced the abyss. He opened his trusty VB6 IDE. The project loaded with the familiar splash of icons. He stared at the TextBox where, for two decades, a barcode scanner had simply typed a 12-digit number and pressed [ENTER]. qr code in vb6

Now, the new scanner was a USB device that emulated a keyboard. When Martin scanned a test QR code—a tiny sticker from a shipping crate—the text box filled with a string that looked like nonsense:

DT=20231115,CTNR=MSCU9876543,SEAL=AB123,WG=25400

It wasn’t a number. It was a sentence. A comma-separated list of keys and values. The entire backend of Invntrak was built on the assumption that a container ID was exactly 11 alphanumeric characters. Anything else caused an overflow error.

Martin tried the simplest thing. He hooked the Text_Change event.

Private Sub txtScan_Change()
    Dim raw As String
    raw = txtScan.Text
' The old way
If Len(raw) = 11 Then
    Call FindContainer(raw)
Else
    ' The new reality
    MsgBox "Invalid barcode format.", vbCritical
    txtScan.Text = ""
End If

End Sub

Every scan triggered the error. The crane operators would riot. Martin’s perfect, deterministic world had cracked. ' Basic QR code generator for simple text

At minimum, you can create a simple 21x21 QR code (Version 1) by hardcoding a matrix or using a lookup table. A full implementation is beyond one article, but here is a skeleton for drawing a bitmap from an array:

Private Sub DrawQRMatrix(matrix() As Integer, ByVal size As Integer)
    Dim bmp As New Bitmap(size * 10, size * 10) ' Assuming you have a reference to GDI+
    Dim g As Graphics = Graphics.FromImage(bmp)
    Dim cellSize As Integer = 10
For x As Integer = 0 To size - 1
    For y As Integer = 0 To size - 1
        If matrix(x, y) = 1 Then
            g.FillRectangle(Brushes.Black, x * cellSize, y * cellSize, cellSize, cellSize)
        Else
            g.FillRectangle(Brushes.White, x * cellSize, y * cellSize, cellSize, cellSize)
        End If
    Next
Next
' Save or display bmp

End Sub

Note: True VB6 GDI operations are slow and error-prone. For production, avoid this method.

Private Sub GenerateQRCode_API(ByVal Text As String, ByVal Size As Integer)
    Dim URL As String
    Dim XMLHttp As Object
    Dim ByteData() As Byte
' Google Charts API URL
URL = "https://chart.googleapis.com/chart?chs=" & Size & "x" & Size & _
      "&cht=qr&chl=" & URLEncode(Text) & "&choe=UTF-8"
' Download image
Set XMLHttp = CreateObject("MSXML2.XMLHTTP")
XMLHttp.Open "GET", URL, False
XMLHttp.Send
If XMLHttp.Status = 200 Then
    ByteData = XMLHttp.responseBody
    SaveByteArrayToFile ByteData, "C:\qrcode.png"
    Picture1.Picture = LoadPicture("C:\qrcode.png")
End If

End Sub
Private Function URLEncode(ByVal Text As String) As String
Dim i As Integer
Dim ch As String
URLEncode = ""
For i = 1 To Len(Text)
    ch = Mid(Text, i, 1)
    If (ch Like "[A-Za-z0-9]") Or (ch = ".") Or (ch = "-") Or (ch = "_") Then
        URLEncode = URLEncode & ch
    ElseIf ch = " " Then
        URLEncode = URLEncode & "+"
    Else
        URLEncode = URLEncode & "%" & Hex(Asc(ch))
    End If
Next i

End Function
Private Sub SaveByteArrayToFile(ByRef Data() As Byte, ByVal FilePath As String)
Dim FileNum As Integer
FileNum = FreeFile
Open FilePath For Binary As FileNum
Put #FileNum, , Data
Close FileNum
End Sub

Visual Basic 6.0 (VB6), despite being released over two decades ago, remains a workhorse in corporate environments. Many legacy systems—inventory trackers, point-of-sale (POS) software, warehouse management tools, and manufacturing execution systems—still run flawlessly on VB6.

With the explosion of smartphone-based scanning and digital labeling, the need to integrate QR codes into these legacy applications has become critical. QR codes can encode product IDs, URLs, serial numbers, or even entire JSON payloads.

However, VB6 does not natively support QR code generation or decoding. This article will walk you through every method available—from third-party libraries to API calls and pure VB6 implementations.

To bridge this gap, we have three primary strategies: