The code behind Barcode.asp
<%
@ LANGUAGE = VBScript %>
<% Option Explicit %>
<html>
<head>
<title>ActiveX Asp Test</title>
</head>
<body>
<div align="center">
<table width="500" border="0">
<tr>
<td>
<h1 align="center"><font size="5" color="#000099">TAL
Bar Code ActiveX Plus <br>
- Active Server Page Example</font></h1>
</td>
</tr>
<tr>
<td>
<h2><font face="Arial" size="3" color="#009999">The
sample application below
was designed to demonstrate how to use the TAL Bar Code ActiveX control
(Plus version) with an Active Server Page.</font></h2>
</td>
</tr>
</table></div>
<%
'If the form
has not yet been submitted the content lenth will be 0 and this code will
be skipped over to display the form, otherwise it will try to generate
the barcode
If Request.ServerVariables("Content_Length")
<> 0 then
'Visitors to
the page will use the HTML form to record information about the barcode
they wish to generate, for example the message to be encoded, the symbology,
and the height of the bars. This ASP Page will look at the form data,
set the Properties of the ActiveX control to those specified on the form,
then generate a barcode image .PNG or .GIF (depending on the Browser since
not all browsers suport .PNG files). This Barcode Image must be saved
on the Server, so we shall specify a folder in which to save it. The filename
has to be different for every visitor or one visitor's barcode will be
overwritten by the next. To this end we shall use an incrementing filename:
"1.png", "2.png", etc. In order for the Server to
"remember" the last filename it created, we must store it somewhere
on the server, so we shall create a text file to store the latest file
number used and then read the last number from the text file and add one
to it when generating the next barcode.
'Create a Constant representing the Maximum number of image files to store
on server. This should exceed expected number of concurrent users or one
user could be overwriting another's image. We shall use this number when
incrementing the filename: If the last filename (number) is the same as
our maximum number of files, then reset the numbering to 1, otherwise
increment the number.
'Note: Since the ActiveX supports several image file types you should
multiply the maximum by the number of file types you offer in your code.
Here we are offering 2 types (.png and .gif). If one user creates 1.png
and then the next time through a user creates 1.gif then the original
#1 file will not be replaced, so eventually you could end up with twice
as many files as you expected. Of course, you can easily add more code
to delete all #1 files before generating a new one.
Const maxFiles = 10
Const nTwipsPerInch = 1440
Const lngPixelsPerInch = 96 'Windows always assumes
there are 96 Pixels per inch regardless of screen resolution
'Folder to store
barcode images
Const ImgDir = "c:\webshare\wwwroot\"
'File to store
current file number info
Const txtFileNum = "c:\webshare\wwwroot\fnum.txt"
Const ForReading = 1, ForWriting=2,
ForAppending = 8 'Input/Output constants
Const TriStateUseDefault = -2 'opens the file using
the system default
Const TriStateTrue = -1 'Opens the file as Unicode
Const TristateFalse = 0 'Opens the file as Ascii
'declare variables (The "Option Explicit"
Statement at the top expects all variable names to be declared, this is
useful because if you mistype a variable name your code will not run,
and tell you why, otherwise it would run but you may get unexpected results
and spend a long time trying to find out why its not working.
dim myBarcode
dim dTime
dim strMessage, strComment, lngSymbology,lngBarHeight,
strFileType
Dim filenum
Dim pxlWidth, pxlHeight
Dim objFS, objTextS
'The following
function is required because we intend to insert a Raster style image
into the resulting web page. The dimensions of a Raster image are dependent
upon the dot resolution of the device used to display it. For example
a graphic that is 300 pixels wide and has 300 rows of pixels displayed
on a printer that has a dot resolution of 300 dots per inch will be one
inch square. But if you display the same image on a computer screen that
has a dot resolution of approx 100 dots per inch, you end up with an image
that is three inches square. When we Query the ActiveX control to find
out it's height and Width the returning information is in "Twips".
In order to Set the Height and Width Properties of the <IMG> tag,
we need this information to be converted into Pixels.
Function
ConvertTwipsToPixels(lngTwips)
ConvertTwipsToPixels = (lngTwips
* lngPixelsPerInch)/ nTwipsPerInch
End Function
'The Following
functions allow reading and writing to a text file on the server
Function
GetFileNum()
Set objFS = Server.CreateObject("Scripting.FileSystemObject")
'open and read file number from file
Set objTextS = objFS.OpenTextFile(txtFileNum,
ForReading, TriStateFalse)
Filenum = objTextS.Readline
objTextS.Close
'Since the filenumber is stored as a string we must
convert it to an integer, otherwise when we try to add "1" to
the number the ASP interpreter will assume we are mistaken because text
cannot be treated as a number and will ignore our request.
Getfilenum = cInt(filenum) 'cInt is a built in function
'destroy objects
Set objFS = nothing
Set objTextS = nothing
End Function
Function
SetFileNum(newFileNumber)
Set objFS = Server.CreateObject("Scripting.FileSystemObject")
'Write the new file number to the text file
Set objTextS = objFS.OpenTextFile(txtFileNum,
ForWriting, TriStateFalse)
objTextS.WriteLine newFileNumber
objTextS.Close
SetFileNum = 1
Set objFS = nothing
Set objTextS = nothing
End Function
'Read last file
number from the file by calling the GetFileNum function above.
filenum = GetFileNum
'if last file
number was less than maximum number of files, increment the number, otherwise
reset it to overwrite file #1
If filenum < maxFiles then
filenum = filenum + 1
Else
filenum = 1
End If
'Write the new
file number to the text file ready for the next pass
SetFileNum filenum
'Get the form
information from the server
strMessage = Trim(Request.Form("txtMessage"))
strComment = Trim(Request.Form("txtComment"))
lngSymbology = Trim(Request.Form("symbology"))
strFileType = Trim(Request.Form("cboImageFormat"))
'get the current
Server time
dTime = Time
'Create an "instance"
of TAL Active X control
Set myBarcode = Server.CreateObject("TALBarCd.TALBarCd.1")
'set some barcode
properties with data from the form
myBarcode.Message = strMessage
myBarcode.Comment = strComment
myBarcode.Symbology = lngSymbology
'set other properties by "hard coding"
the values if you wish
myBarcode.BarHeight = 1000
myBarcode.NarrowBarWidth = 13
myBarcode.ForeColor = "0"
myBarcode.BackColor = "16777215"
'Note: Properties
that you do not set will use their default values
'save barcode
in chosen directory in a format suitable for the browser (The form uses
JavaScript to evaluate the browser, then writes the most suitable filetype
to a "hidden" field in the form called "Imagetype".
When we requested the form information from the server "Imagetype"
was saved into a new variable called "strFileType". Below we
concatenate 3 variables together in order to save the barcode:
myBarcode.SaveBarCode ImgDir & filenum & "." & strFileType
'Since our ImgDir
is stored in a constant above as "c:\webshare\wwwroot\", filenum
will be a number between 1 and 10 (since 10 is the maximum number of files
we wish to store on the server) and strFileType will be either "PNG"
or "GIF". The "&" character simply joins the three
variables together in order to create a single string, for example ""c:\webshare\wwwroot\6.png"
'Get height and
width for display in Browser
'(these properties only exist on the plus version of the TAL active X
control)
pxlWidth = ConvertTwipsToPixels(myBarcode.Width)
pxlHeight = ConvertTwipsToPixels(myBarcode.Height)
'reset objects
to free memory resources on the server
set myBarcode = nothing
%>
<div align="center"><!--
Print Server time -->
This server's time is:
<%= dTime %><br>
<!-- Display
barocode image -->
<img src='<%=
filenum & "." & strFileType & "' Height="
& pxlHeight & " Width=" & pxlWidth %>'></div>
<% Else %>
<!-- Display HTML Form --><form method="Post" name="BarCodeForm"
Action="Barcode.asp">
<div align="center">
<table width="500" border=0 bgcolor="#efefe7">
<tbody>
<tr>
<td align=right width="50%" bgcolor=#efefe7><small>Bar
code message:</small></td>
<td width="50%" bgcolor=#efefe7>
<input tabindex=1 size=12
value=12345678901 name="txtMessage">
</td>
</tr>
<tr>
<td align=right width="50%"><small>Comment:</small></td>
<td width="50%">
<input tabindex=2 size=12 name="txtComment">
</td>
</tr>
<tr>
<td align=right width="50%" bgcolor=#efefe7><small>Comment
Alignment:</small></td>
<td width="50%" bgcolor=#efefe7>
<select tabindex=3 size=1
name="commentalignment">
<option value=0 selected>Left Align</option>
<option value=1>Center Align</option>
<option
value=2>Right Align</option>
</select>
</td>
</tr>
<tr>
<td align=right width="50%"><small>Bar Height (mils):</small></td>
<td width="50%">
<input tabindex=4 size=12 value=1000 name="barheight">
</td>
</tr>
<tr>
<td align=right width="50%" bgcolor=#efefe7><small>Narrow
Bar Width (mils):</small></td>
<td width="50%" bgcolor=#efefe7>
<input tabindex=5 size=12 value=13
name="narrowbarwidth">
</td>
</tr>
<tr>
<td align=right width="50%"><small>Bar Code Symbology:</small></td>
<td width="50%">
<select tabindex=6 size=1 name="symbology">
<option
value=0 selected>Code 39</option>
<option value=1>Full ASCII 39</option>
<option value=2>Code 39 HIBC</option>
<option
value=3>Codabar</option>
<option value=4>Code 93</option>
<option
value=5>Code 128</option>
<option value=6>UCC/EAN 128</option>
<option value=7>Interleaved 2 of 5</option>
<option
value=8>PostNET</option>
<option value=9>UPC - A</option>
<option
value=10>UPC - E</option>
<option value=11>EAN - 8</option>
<option value=12>EAN - 13</option>
<option
value=13>Bookland</option>
<option value=14>MSI/Plessey</option>
<option value=15>PDF417</option>
<option value=16>Aztec Code</option>
<option value=17>Data Matrix</option>
<option
value=18>MaxiCode</option>
</select>
</td>
</tr>
<tr>
<td align=right width="50%"
bgcolor=#efefe7><small>Rotation:</small></td>
<td width="50%" bgcolor=#efefe7>
<select tabindex=7 size=1
name="rotation">
<option value=0 selected>0 degrees</option>
<option
value=1>90 degrees</option>
<option value=2>180 degrees</option>
<option value=3>270 degrees</option>
</select>
</td>
</tr>
<tr>
<td align=right width="50%"><small>Foreground Color:</small></td>
<td width="50%">
<select tabindex=8 size=1 name="forecolor">
<option
value=0 selected>Black</option>
<option value=255>Red</option>
<option value=65280>Green</option>
<option
value=16711680>Blue</option>
</select>
</td>
</tr>
<tr>
<td align=right width="50%" bgcolor=#efefe7><small>Background
Color:</small></td>
<td width="50%" bgcolor=#efefe7>
<select tabindex=9 size=1
name="backcolor">
<option value=16777215 selected>White</option>
<option value=255>Red</option>
<option value=65280>Green</option>
<option value=16711680>Blue</option>
</select>
</td>
</tr>
<tr>
<td align=right width="50%" bgcolor=#efefe7>Image Format:</td>
<td width="50%" bgcolor=#efefe7>
<select name="cboImageFormat">
<option value=".png">PNG</option>
<option value=".gif" selected>GIF</option>
</select>
</td>
</tr>
<tr>
<td valign=top align=right width="50%" height=44>
<div align="right">
<input tabindex=10 type="checkbox" CHECKED value=ON
name="quietzones">
<small>Include Quiet Zones</small></div>
</td>
<td valign=top width="50%" height=44>
<input language=JavaScript
tabindex=11 type="checkbox" value=ON name="bearerbars">
<small>Include Bearer Bars</small></td>
</tr>
<tr>
<td valign=top align=right colspan="2" height=44>
<div align="center">
<input type=hidden name=scrHeight>
<input type=hidden
name=scrWidth>
<input type=hidden name="Browser">
<input type=hidden
name="Version">
<input tabindex=12 type="submit" value="Submit"
name="Submit">
</div>
</td>
</tr>
</tbody>
</table></div>
</FORM>
<% End If %></BODY></HTML>
Related Links
Introduction to Active Server Pages
Printing From Active Server Pages
Using TAL Bar Code ActiveX Plus with PERL CGI
Scripts
Using the TAL Bar Code ActiveX Plus with
Active Server Pages
See the fully working ASP example of the TAL Bar Code ActiveX in action
at www.freebarcodes.com!
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