PrintPreview: Added code to identify the printer default duplex value.

chrome/browser/resources/print_preview/copies_settings.js

 // 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.
 
 cr.define('print_preview', function() {
   'use strict';
 
   /**
    * Creates a CopiesSettings object.
    * @constructor
    */
   function CopiesSettings() {
     this.copiesOption_ = $('copies-option');
     this.textfield_ = $('copies');
     this.incrementButton_ = $('increment');
     this.decrementButton_ = $('decrement');
     // Minimum allowed value for number of copies.
     this.minValue_ = 1;
     // Maximum allowed value for number of copies.
     this.maxValue_ = 999;
     this.collateOption_ = $('collate-option');
     this.collateCheckbox_ = $('collate');
     this.hint_ = $('copies-hint');
     this.twoSidedCheckbox_ = $('two-sided');
+
+    // Constant values matches printing::DuplexMode enum. Not using const
+    // keyword because it is not allowed by JS strict mode.
+    this.SIMPLEX = 0;
+    this.LONG_EDGE = 1;
+    this.SHORT_EDGE = 2;
+    this.UNKNOWN = -1;
+    // Store the default duplex setting value which we got from the printer.
+    this.printerDefaultDuplexValue_ = this.UNKNOWN;
   }
 
   cr.addSingletonGetter(CopiesSettings);
 
   CopiesSettings.prototype = {
     /**
      * The number of copies represented by the contents of |this.textfield_|.
      * If the text is not valid returns |this.minValue_|.
      * @type {number}
      */
@@ skipping 14 matching lines @@
 
     /**
      * Getter method for |twoSidedCheckbox_|.
      * @type {HTMLInputElement}
      */
     get twoSidedCheckbox() {
       return this.twoSidedCheckbox_;
     },
 
     /**
-     * Gets the duplex mode for printing.
+     * Gets the duplex mode information for printing.
      * @return {number} duplex mode.
      */
-     get duplexMode() {
-      // Constant values matches printing::DuplexMode enum. Not using const
-      // keyword because it is not allowed by JS strict mode.
-      var SIMPLEX = 0;
-      var LONG_EDGE = 1;
-      return !this.twoSidedCheckbox_.checked ? SIMPLEX : LONG_EDGE;
+    get duplexMode() {
+      // On Windows, some printer doesn't specify their duplex values in the
+      // printer schema. If the printer duplex value is UNKNOWN, it is better
+      // to assign either "0" or "1" in DEVMODE structure according to user
+      // selected duplex value.
+      // Ref bug: http://code.google.com/p/chromium/issues/detail?id=89204

[vandebo (ex-Chrome), 2011/09/03 00:58:26]

http://crbug.com/89204

[kmadhusu, 2011/09/03 02:44:53]

Done.

+      return !this.twoSidedCheckbox_.checked ?

[vandebo (ex-Chrome), 2011/09/03 00:58:27]

Double trinary is pretty ugly... how about if, else if, else

[kmadhusu, 2011/09/03 02:44:53]

Done.

+             this.SIMPLEX :
+             (this.printerDefaultDuplexValue == this.UNKNOWN ?
+                 this.SHORT_EDGE : this.LONG_EDGE);

[vandebo (ex-Chrome), 2011/09/03 00:58:27]

I wonder if it would be clearer to define this.DUPLEX = 1, and use that here.

[kmadhusu, 2011/09/03 02:44:53]

Yeah it will be consistent with the comment. Done.

     },
 
     /**
      * @return {boolean} true if |this.textfield_| is empty, or represents a
      *     positive integer value.
      */
     isValid: function() {
       return !this.textfield_.value || isPositiveInteger(this.textfield_.value);
     },
 
@@ skipping 73 matching lines @@
      * @private
      */
     onPrinterCapabilitiesUpdated_: function(e) {
       if (e.printerCapabilities.disableCopiesOption) {
         fadeOutElement(this.copiesOption_);
         $('hr-before-copies').classList.remove('invisible');
       } else {
         fadeInElement(this.copiesOption_);
         $('hr-before-copies').classList.add('invisible');
       }
-      this.twoSidedCheckbox_.checked = e.printerCapabilities.setDuplexAsDefault;
+      this.printerDefaultDuplexValue =
+          e.printerCapabilities.printerDefaultDuplexValue;
+      if (this.printerDefaultDuplexValue >= 0)

[vandebo (ex-Chrome), 2011/09/03 00:58:27]

!= UNKNOWN ?

[kmadhusu, 2011/09/03 02:44:53]

Done.

+        this.twoSidedCheckbox_.checked = this.printerDefaultDuplexValue;
     },
 
     /**
      * Listener triggered when |incrementButton_| is clicked.
      * @private
      */
     onIncrementButtonClicked_: function() {
       this.onButtonClicked_(1);
     },
 
@@ skipping 36 matching lines @@
         fadeOutElement(this.hint_);
       }
       this.hint_.setAttribute('aria-hidden', this.isValid());
     }
   };
 
   return {
     CopiesSettings: CopiesSettings,
   };
 });