This is what I called a revolutionary for the web based application to handle RAW printing. Somehow, I found this Java applet named
jZebra & it worked successfully as same as 16-bit console printing operation - the objective is prohibiting paper to rolled up one sheet full. Different with other extension “add-on” (eg:
php_printer module on PHP) which is executed on server, jZebra operated on client side – since it Java based applet, you know it’ll depends on existing JRE package in each client. But - nevertheless - printing in a small paper (eg: receipt or bill) from web based application is not a problem anymore.
A couple years ago, I was thinking about to create a small win32 application purposed to take job RAW printing on LAN on
here and
there (with AssignPrn function available on Delphi), it’s done to print locally but unfortunately failed to handle network printing session – especially on non Windows machine (Linux ~ with
CrossOver “limitation” capabilities). Anyway, you can read the online documentation of jZebra or try the sample directly provided over Google code page where it
published for free.
On current article, I’d like to share about my experiment on exploring jZebra, including a short review and a bit modification of HTML page so that jZebra will have more flexible to use. Before continue reading this & decide to use it, I suggest you to read first of jZebra manual whether it suitable to your need or not.
At first, I try to create an HTML page, embed the applet – minor modification from the example - & store it on local Apache web server. The picture below explains what I’ve done above:
Image above shows jZebra initialization process. Once the applet executed, each & every browser will need a confirmation window to run Java applet. It signed by small loading logo rolling where the embed applet placed on a page.
When printer doesn’t exist, the applet will return fail code says that the printer is not yet ready. I switch back to Printer & Fax Control Panel & found that there’s no printer configured, while I still use FinePrint screen printing application as my default printer on
my netbook.
Any printing process regarding to unsuccessful printer communication will raise failed information just like below picture.
For the experiment, I then rename the “
FinePrint” printer name to “
zebra”
And … voila, the applet status says it ready.
Press print button & below picture display what’s happened on Windows printer status. You can see that the document name is “
Java Printing”.
The printer on my experiment particularly used is LX-300 with USB plug cable. At the same time I press the Print button, the print will printing on paper directly & it stop to the end of string. It has exact behavior like DOS printing as I told before.
The above experiment I created from small modification of jZebra example. Note that information status as seen on above picture is based on AJAX, I decide to modified the source & use AJAX rather than manual common button (Detect Printer) for ease-of-use & compact source only. Below source define small part of
index.html where I attach JavaScript main function:
...
<script type="text/javascript" src="js/jzebra.js"></script>
<body onLoad="detectPrinter()">
…
<table width="75%" border="0" align="center" cellpadding="0" cellspacing="0">
<tr> <td colspan="2" bgcolor="#000000"><span id="printerStatusBar">Loading...</span></td></tr>
<tr> <td width="47%"><form name="form1" method="post" >
String untuk dicetak<br>
<textarea name="struk" cols="50" rows="7" id="struk"></textarea>
<br><input name="button" type=button onClick="printStruk(form1.struk.value)" value="Test Cetak">
<input name="button2" type=button onClick="print64()" value="Test Cetak (Base64)">
<input type="reset" name="Reset" value="Reset"></form></td>
<td width="53%">
<applet name="jZebra" code="jzebra.RawPrintApplet.class" archive="js/jzebra.jar" width="100" height="100">
<param name="printer" value="zebra">
<param name="sleep" value="200"></applet></td></tr></table>
…
While here below is the core of JavaScript function:
function detectPrinter()
{
var applet = document.jZebra;
if (applet != null)
{
applet.findPrinter("zebra");
while (!applet.isDoneFinding())
{
// Wait
}
var ps = applet.getPrintService();
if (ps == null) var info="Printer belum siap";
else var info="Printer \"" + ps.getName() + "\" siap";
}
else
var info="Java Runtime belum siap!";
document.getElementById("printerStatusBar").innerHTML=info;
window.setTimeout('detectPrinter()',5000);
}
function printStruk(str)
{
var applet = document.jZebra;
if (applet != null)
{
// Plain Text
str=returnEnter(str);
applet.append(str);
// Send to the printer
applet.print();
while (!applet.isDonePrinting())
{
// Wait
}
var e = applet.getException();
if (e == null) var info="Printed Successfully";
else var info="Error: " + e.getLocalizedMessage();
}
else
{
var info="Printer belum siap";
}
document.getElementById("printerStatusBar").innerHTML=info;
}
function returnEnter(dataStr)
{
return dataStr.replace(/(\r\n|\r|\n)/g, "\n");
}
From the above picture, the example page now contains a textarea input. This purposed for user to print what they enter on it. So that this prototype will more flexible to use, since each of HTML page only embedding the JavaScript core function when custom specified page need the RAW printing function. Have a good try & share your comment below.
Labels: AJAX, JavaScript, PHP, Printing, Programming, Web Programming
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