Print Preview: Adding UI for margin settings.

chrome/browser/resources/print_preview/preview_area.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() {
+  'strict';
+
+  /**
+   * Creates a PreviewArea object.

[Evan Stade, 2011/10/05 03:05:23]

explain what PreviewArea is

[dpapad, 2011/10/05 16:39:49]

Done.

+   * @constructor
+   */
+  function PreviewArea() {
+    // The embedded pdf plugin object.
+    this.pdfPlugin_ = null;
+
+    // True if the pdf document is loaded in the preview area.
+    this.pdfLoaded_ = false;
+
+    // Contains the zoom level just before a new preview is requested so the
+    // same zoom level can be restored.
+    this.zoomLevel_ = null;
+    // Contains the page offset values just before a new preview is requested so
+    // the same scroll amount can be maintained.
+    this.pageOffset_ = null;
+  }
+
+  cr.addSingletonGetter(PreviewArea);
+
+  PreviewArea.prototype = {
+    /**
+     * The width of the plugin area excluding any visible scrollbars in pixels.
+     * @type {number}
+     */
+    get width() {
+      return this.widthPercent * this.pdfPlugin_.offsetWidth;
+    },
+
+    /**
+     * The height of the plugin area excluding any visible scrollbars in pixels.
+     * @type {number}
+     */
+    get height() {
+      return this.heightPercent * this.pdfPlugin_.offsetHeight;
+    },
+
+    /**
+     * The width of the plugin area excluding any visible scrollbars in percent.
+     * @type {number}
+     */
+    get widthPercent() {
+      var width = this.pdfPlugin_.getWidth();
+      var scrollbarWidth = this.pdfPlugin_.getVerticalScrollbarThickness();
+      return (width - scrollbarWidth) / width;
+    },
+
+    /**
+     * The height of the plugin area excluding any visible scrollbars in
+     *   percent.
+     * @type {number}
+     */
+    get heightPercent() {
+      var height = this.pdfPlugin_.getHeight();
+      var scrollbarHeight = this.pdfPlugin_.getHorizontalScrollbarThickness();
+      return (height - scrollbarHeight) / height;
+    },
+
+    get pdfLoaded() {
+      return this.pdfLoaded_;
+    },
+
+    set pdfLoaded(pdfLoaded) {
+      this.pdfLoaded_ = pdfLoaded;
+    },
+
+    /**
+     * @return {print_preview.Rect} A rectangle describing the postion of the
+     *   most visible page normalized with respect to the total height and width
+     *   of the plugin.
+     */
+    getPageLocationNormalized: function() {
+      var pluginLocation =
+          this.pdfPlugin_.getPageLocationNormalized().split(';');
+      return new print_preview.Rect(parseFloat(pluginLocation[0]),
+                                    parseFloat(pluginLocation[1]),
+                                    parseFloat(pluginLocation[2]),
+                                    parseFloat(pluginLocation[3]));
+    },
+
+    /**
+     * Resets the state variables of |this|.
+     */
+    resetState: function() {
+      if (this.pdfPlugin_) {
+        this.zoomLevel_ = this.pdfPlugin_.getZoomLevel();
+        this.pageOffset_ = new print_preview.Point(
+            this.pdfPlugin_.pageXOffset(),
+            this.pdfPlugin_.pageYOffset());
+      }
+      this.pdfLoaded_ = false;
+    },
+
+    /**
+     * Adds event listeners for various events.
+     * @private
+     */
+    addEventListeners: function() {
+      document.addEventListener('PDFLoaded',
+                                this.onPDFLoaded_.bind(this));
+    },
+
+    /**
+     * Listener executing when a PDFLoaded event occurs.
+     * @private
+     */
+    onPDFLoaded_: function() {
+      this.pdfPlugin_ = $('pdf-viewer');
+      this.pdfLoaded_ = true;
+      if (this.zoomLevel_ != null && this.pageOffset_ != null) {
+        this.pdfPlugin_.setZoomLevel(this.zoomLevel_);
+        this.pdfPlugin_.setPageXOffset(this.pageOffset_.x);
+        this.pdfPlugin_.setPageYOffset(this.pageOffset_.y);
+      } else {
+        this.pdfPlugin_.fitToHeight();
+      }
+    }
+  };
+
+  return {
+    PreviewArea: PreviewArea,
+  };
+});