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Published: Friday, August 25, 2000

Dynamically Generating I25 Bar Codes, Part 2

By Daniel Goncalves


  • Read Part 1

  • In Part 1 we looked at creating the I25Encode() function. We now need to write our ASP code that will take the results of this function and display the correct bar codes!

    - continued -

    Creating An Apropriated Graphics Set
    Now we must create a simple graphics (GIF) set. One for the narrow bar (black, 2 pixels wide), one for the narrow space (white, 2 pixels wide), one for the wide bar (black, 4 pixels wide) and one for the wide space (white 4 pixels wide), all these graphics can have 39 pixels height or more. I have included a ZIP file containing these graphics. The file names are:

    File NameDescriptionImage
    nb.gifNarrow barnb.gif
    ns.gifNarrow spacens.gif
    wb.gifWide barwb.gif
    ws.gifWide spacews.gif
    These graphics will be used to generate the resulting HTTP that will mount the full barcode through <IMG ...> tags.

    Writing The Final Code
    Now we'll write the final code. This code will read the string returned by I25Encode() function and generate the resulting HTTP using our gifs. (While I don't show the I25Encode() function in the script below, it must be included (either cut and pasted into the file or via a server-side include.)

    <HTML>
    <HEAD><TITLE>Interleaved 2-of-5 Example</TITLE></HEAD>
    <%
       ' Ensure that the I25Encode function is in this file...
       ' (For this example it has been removed for brevity
    %>
    
    <BODY BGCOLOR='#FFFFFF'>
    <P><FONT FACE='Verdana, Arial' SIZE='1'>
    Enter the number to be encoded as Interleaved 2-of-5 Specification.
    </FONT></P>
    
    <FORM NAME='I25' ACTION='i25.asp' METHOD='post'>
       <INPUT TYPE='text' NAME='txtNUM'>
       <INPUT TYPE='hidden' NAME='hidFORM' VALUE='fromFORM'>
       <INPUT TYPE='submit'>
    </FORM>
    <P> </P>
    <P><FONT FACE='Verdana, Arial' SIZE='1'>
    <%
       If Request("hidFORM") = "fromFORM" Then
          sMyI25 = I25Encode(Request("txtNUM"))
          If (sMyI25 = "") Then
             Response.Write """" & Request("txtNUM") & _
                            """ is invalid. Try another number."
          Else
             Dim iPos, sGIF, bBAR
             bBAR = True
    
             For iPos = 1 To Len(sMyI25)
                 If (bBar) Then 
                    'Bar
                    sGIF = Mid(sMyI25, iPos, 1) & "b.gif"
                 Else
                    'Space
                    sGIF = Mid(sMyI25, iPos, 1) & "s.gif"
                 End If
    
                 Response.Write "<IMG SRC='" & sGIF & "'>"
    
                 bBar = Not bBar
             Next
          End if
       End If
    %>
    </FONT></P>
    </BODY>
    </HTML>
    

    (If you are interested in seeing the results, go ahead and give the live demo a whirl!) Well done and Happy Programming!

  • By Daniel Goncalves


    Attachments:

  • Try the live demo!
  • View the source for the I25Encode function in text format
  • Download the Bar graphics in ZIP format
  • Read Generating Dynamic Bar Code on a Web Page (using Code 39 barcodes)


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