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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!

    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)


  • Article Information
    Article Title: Dynamically Generating I25 Bar Codes, Part 2
    Article Author: Daniel Goncalves
    Published Date: Friday, August 25, 2000
    Article URL: http://www.4GuysFromRolla.com/webtech/082500-1.2.shtml


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