Print Preview: Hook up the print button to initiate printing without displaying a print dialog.

chrome/browser/resources/print_preview.js

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 var localStrings = new LocalStrings();
 var hasPDFPlugin = true;
 
 /**
  * Window onload handler, sets up the page.
  */
 function load() {
+  $('print-button').addEventListener('click', printFile);
+
   $('cancel-button').addEventListener('click', function(e) {
     window.close();
   });
 
   chrome.send('getPrinters');
 };
 
 /**
+ * Parse page range text.
+ * Eg: If page range is specified as "1-3,7-9,8". Create an array with three
+ * elements. Each array element contains the range information.
+ * [{from:1, to:3}, {from:7, to:9}, {from:8, to:8}]
+ * TODO (kmadhusu): Check for invalid characters.
+ */
+function pageRange() {
+  var pageRangeParams;
+  var pageRangesInfo = new Array();
+  var pageRangeText = $('pages').value;
+  var pageRangeList = pageRangeText.split(",");

[arv (Not doing code reviews), 2011/02/16 23:54:41]

Use single quotes

[kmadhusu, 2011/02/17 19:20:31]

Done.

+  for (var i = 0; i < pageRangeList.length; i++) {
+    var temp_range = pageRangeList[i].split("-");

[James Hawkins, 2011/02/16 22:58:21]

What if the page range text is malformed?

[arv (Not doing code reviews), 2011/02/16 23:54:41]

no underscores in js

[kmadhusu, 2011/02/17 19:20:31]

Done.

[kmadhusu, 2011/02/17 19:20:31]

Added isValidPageRange() function to validate the page range information.

+    if (temp_range.length > 1) {
+      pageRangeParams = JSON.stringify({"from" : parseInt(temp_range[0]),

[arv (Not doing code reviews), 2011/02/16 23:54:41]

parseInt(n, 10) please

[kmadhusu, 2011/02/17 19:20:31]

Done.

+                                        "to" : parseInt(temp_range[1])});
+    } else {
+      pageRangeParams = JSON.stringify({"from" : parseInt(temp_range[0]),

[arv (Not doing code reviews), 2011/02/16 23:54:41]

It seems like you can do the from to assignment outside the if to reduce code
duplication.

[kmadhusu, 2011/02/17 19:20:31]

Done.

+                                        "to" : parseInt(temp_range[0])});
+    }
+    pageRangesInfo.push(pageRangeParams);

[arv (Not doing code reviews), 2011/02/16 23:54:41]

Why are we using strings in here?

[kmadhusu, 2011/02/17 19:20:31]

Rather than creating json strings, I modified the code to create an array of
Objects.

+  }
+  return pageRangesInfo;
+}
+
+function printFile() {
+  var selected_printer = $('printer-list').selectedIndex;
+  var printer_name = $('printer-list').options[selected_printer].textContent;
+  var page_range = pageRange();
+  var print_all = $('all-pages').checked;
+  var two_sided = $('two-sided').checked;
+  var copies = $('copies').value;
+  var collate = $('collate').checked;
+  var layout = $('layout').options[$('layout').selectedIndex].value;
+  var color = $('color').options[$('color').selectedIndex].value;
+
+  var job_settings = JSON.stringify({"printerName" : printer_name,

[arv (Not doing code reviews), 2011/02/16 23:54:41]

no ws before :

[kmadhusu, 2011/02/17 19:20:31]

Done.

+                                     "pageRange" : page_range,

[arv (Not doing code reviews), 2011/02/16 23:54:41]

Won't this lead to double json encoding?

[kmadhusu, 2011/02/17 19:20:31]

Fixed. |pageRange| is now an array of objects. JSON encoding is done only once. 

+                                     "printAll" : print_all,
+                                     "twoSided" : two_sided,
+                                     "copies" : copies,
+                                     "collate" : collate,
+                                     "layout" : layout,
+                                     "color" : color});
+  chrome.send('print', [job_settings]);
+}
+
+/**
  * Fill the printer list drop down.
  */
 function setPrinters(printers) {
   if (printers.length > 0) {
     for (var i = 0; i < printers.length; ++i) {
       var option = document.createElement('option');
       option.textContent = printers[i];
       $('printer-list').add(option);
     }
   } else {
@@ skipping 34 matching lines @@
   if (!pdfPlugin.onload) {
     hasPDFPlugin = false;
     mainView.removeChild(pdfPlugin);
     $('no-plugin').classList.remove('hidden');
     return;
   }
   pdfPlugin.onload('onPDFLoad()');
 }
 
 window.addEventListener('DOMContentLoaded', load);