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

chrome/browser/resources/print_preview.js

Index: chrome/browser/resources/print_preview.js
diff --git a/chrome/browser/resources/print_preview.js b/chrome/browser/resources/print_preview.js
index 6c3aee2931c4f0e13ab02b4fbc390e98a67eb779..94e802626399a19d8e9042cd02a41d15ab5fa216 100644
--- a/chrome/browser/resources/print_preview.js
+++ b/chrome/browser/resources/print_preview.js
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -9,9 +9,8 @@ var hasPDFPlugin = true;
  * Window onload handler, sets up the page.
  */
 function load() {
-  $('print-button').addEventListener('click', function(e) {
-    chrome.send('print');
-  });
+  $('print-button').addEventListener('click', printFile);
+
   $('cancel-button').addEventListener('click', function(e) {
     window.close();
   });
@@ -20,6 +19,78 @@ function load() {
 };
 
 /**
+ * Page range text validation.
+ * Returns true if |printFromText| and |printToText| are valid page numbers.
+ * TODO (kmadhusu): Get the expected page count and validate the page range
+ * with total number of pages.
+ */
+function isValidPageRange(printFromText, printToText) {
+  var numericExp = /^[0-9]+$/;
+  if (printFromText.match(numericExp) && printToText.match(numericExp)) {

[arv (Not doing code reviews), 2011/02/21 02:00:05]

match is useful to get the matched groups. If all you care about is if it
matched test seems cleaner.

if (numerucExp.test(printFromText) ... ) 

[kmadhusu, 2011/02/22 02:56:34]

Done.

+    var printFrom = parseInt(printFromText, 10);

[arv (Not doing code reviews), 2011/02/21 02:00:05]

or just Number(printFromText) since you only allow [0-9]+ anyway.

[kmadhusu, 2011/02/22 02:56:34]

Done.

+    var printTo = parseInt(printToText, 10);
+    if ((printFrom > 0) && (printTo > 0) && (printFrom <= printTo))

[arv (Not doing code reviews), 2011/02/21 02:00:05]

Too many parentheses

[arv (Not doing code reviews), 2011/02/21 02:00:05]

How can printFrom be less than 0 when the regexp only allows [0-9]?

parseInt returns NaN when it cannot parse an int.

[kmadhusu, 2011/02/22 02:56:34]

Fixed.

[kmadhusu, 2011/02/22 02:56:34]

Fixed.

+      return true;
+  }
+  return false;
+}
+
+/**
+ * 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): Handle invalid characters.
+ */
+function getPageRanges() {
+  var pageRangesInfo = new Array();

[arv (Not doing code reviews), 2011/02/21 02:00:05]

Use []

[kmadhusu, 2011/02/22 02:56:34]

Done.

+  var pageRangeText = $('pages').value;
+  var pageRangeList = pageRangeText.split(',');
+  for (var i = 0; i < pageRangeList.length; i++) {
+    var tempRange = pageRangeList[i].split('-');
+    var printFrom;
+    var printTo;
+    if (tempRange.length > 1) {
+      printFrom = tempRange[0];
+      printTo = tempRange[1];
+    } else {
+      printFrom = tempRange[0];
+      printTo = tempRange[0];
+    }
+    // Validate the page range information.
+    if (isValidPageRange(printFrom, printTo)) {
+      var pageRangeParams = new Object();

[arv (Not doing code reviews), 2011/02/21 02:00:05]

Use an object literal

pageRangesInfo.push({
  from: parseInt(printFrom, 10),
  ...
});

[kmadhusu, 2011/02/22 02:56:34]

Done.

+      pageRangeParams.from = parseInt(printFrom, 10);
+      pageRangeParams.to = parseInt(printTo, 10);
+      pageRangesInfo.push(pageRangeParams);
+    }
+  }
+  return pageRangesInfo;
+}
+
+function printFile() {
+  var selectedPrinter = $('printer-list').selectedIndex;
+  var printerName = $('printer-list').options[selectedPrinter].textContent;
+  var pageRanges = getPageRanges();
+  var printAll = $('all-pages').checked;
+  var twoSided = $('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 jobSettings = JSON.stringify({"printerName": printerName,

[arv (Not doing code reviews), 2011/02/21 02:00:05]

use single quotes

[kmadhusu, 2011/02/22 02:56:34]

Done.

+                                    "pageRange": pageRanges,
+                                    "printAll": printAll,
+                                    "twoSided": twoSided,
+                                    "copies": copies,
+                                    "collate": collate,
+                                    "layout": layout,
+                                    "color": color});
+  chrome.send('print', [jobSettings]);
+}
+
+/**
  * Fill the printer list drop down.
  */
 function setPrinters(printers) {