Print Preview: Refactoring layout mode related logic to LayoutSettings class.

chrome/browser/resources/print_preview/layout_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 LayoutSettings object. This object encapsulates all settings and
+   * logic related to layout mode (portrait/landscape).
+   * @constructor
+   */
+  function LayoutSettings() {
+    this.layoutOption_ = $('layout-option');
+    this.portraitRadioButton_ = $('portrait');
+    this.landscapeRadioButton_ = $('landscape');
+  }
+
+  cr.addSingletonGetter(LayoutSettings);
+
+  LayoutSettings.prototype = {
+    /**
+     * The div containing all layout related options.
+     * @type {HTMLDivElement}
+     */
+    get layoutOption() {
+      return this.layoutOption_;
+    },
+
+    /**
+     * The radio button corresponding to the portrait option.
+     * @type {HTMLInputElement}
+     */
+    get portraitRadioButton() {
+      return this.portraitRadioButton_;
+    },
+
+    /**
+     * The radio button corresponding to the landscape option.
+     * @type {HTMLInputElement}
+     */
+    get landscapeRadioButton() {
+      return this.landscapeRadioButton_;
+    },
+
+    /**
+     * @return {boolean} true if |this.landscapeRadioButton_| is checked, false
+     *     if not.
+     */
+    isLandscape: function() {
+      return this.landscapeRadioButton_.checked;
+    },
+
+    /**
+     * Adding listeners to all layout related controls. The listeners take care
+     * of altering their behavior depending on |hasPendingPreviewRequest|.
+     */
+    addEventListeners: function() {
+      this.landscapeRadioButton_.onclick = function() {
+        if (!hasPendingPreviewRequest)
+          this.onLayoutButtonClick();
+      }.bind(this);
+      this.portraitRadioButton_.onclick = function() {
+        if (!hasPendingPreviewRequest)
+          this.onLayoutButtonClick();
+      }.bind(this);
+    },
+
+    /**
+     * Listener executing when |this.landscapeRadioButton_| or
+     * |this.portraitRadioButton_| is clicked.
+     */
+    onLayoutButtonClick: function() {
+      // If the chosen layout is same as before, nothing needs to be done.
+      if (printSettings.isLandscape == this.isLandscape())
+        return;
+      setDefaultValuesAndRegeneratePreview();
+    }
+  };
+
+  return {
+    LayoutSettings: LayoutSettings,
+  };
+});