OOP PDF - Add support for "zoom" open pdf parameter

chrome/browser/resources/pdf/pdf.js

 // Copyright 2013 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.
 
 'use strict';
 
 <include src="../../../../ui/webui/resources/js/util.js">
 <include src="pdf_scripting_api.js">
 <include src="viewport.js">
 
@@ skipping 246 matching lines @@
    * @private
    * Notify the plugin to print.
    */
   print_: function() {
     this.plugin_.postMessage({
       type: 'print',
     });
   },
 
   /**
+   * Handle zoom parameter of open PDF parameters. If this
+   * parameter is passed while opening PDF then PDF should be opened
+   * at the specified zoom level.
+   * @param {number} zoom value.
+   */
+  handleZoomParam_: function(paramValue) {
+    var paramValueSplit = paramValue.split(',');
+    if ((paramValueSplit.length != 1) && (paramValueSplit.length != 3))
+      return;
+
+    // User scale of 100 means zoom value of 100% i.e. zoom factor of 1.0.
+    var zoomFactor = parseFloat(paramValueSplit[0]) / 100;
+
+    // Handle #zoom=scale.
+    if (paramValueSplit.length == 1) {
+      this.viewport_.setZoom(zoomFactor);

[Nikhil, 2014/08/19 15:09:42]

setZoom() isn't working as intended. Is this not the correct way to use this?

[raymes, 2014/08/20 00:14:21]

This looks correct. What is it that isn't working? You might need to do some
debugging. Something may be changing the zoom after this call.

[Nikhil, 2014/08/20 04:46:55]

It didn't work as intended since zoom didn't change to what was passed in the
parameter. But if I just attach debugger, pause, and continue execution then it
works fine. Maybe some sort of timing issue?

I wasn't sure if I was calling setZoom() correctly. I'll try to debug this more.

[Nikhil, 2014/08/21 11:36:50]

It wasn't working because chrome.tabs.onZoomChange() listener was changing the
zoom back to 1. I've made a change for this. PTAL.

+      return;
+    }
+
+    // Handle #zoom=scale,left,top.
+    var position = {x: parseFloat(paramValueSplit[1]),

[Lei Zhang, 2014/08/20 00:37:07]

The Adobe open parameters document is rather vague on what units left/top are.
Do we need to do any unit conversion here?

[Nikhil, 2014/08/20 04:46:54]

Yep, it's a bit vague on units. Unlike page which can only take integer values,
the Adobe document says scale, left, and top can be passed as integer or float
values. So I used parseFloat().

Also, do we need NaN check here to make it robust?

+                    y: parseFloat(paramValueSplit[2])};
+    this.viewport_.position = position;
+    this.viewport_.setZoom(zoomFactor);
+  },
+
+  /**
    * @private
    * Handle open PDF parameters. These parameters are mentioned in the URL
    * and specify actions to be performed when opening PDF files.
    * See http://crbug.com/64309 for details.

[raymes, 2014/08/20 00:14:21]

nit: we don't need the crbug link,but a link to a spec document for Open PDF
params would be useful :)

[Nikhil, 2014/08/21 11:36:50]

Done.

    */
   handleOpenPDFParams_: function() {
     var originalUrl = this.streamDetails.originalUrl;
     var paramIndex = originalUrl.search('#');
     if (paramIndex == -1)
       return;
 
     var paramTokens = originalUrl.substring(paramIndex + 1).split('&');
     var paramsDictionary = {};
     for (var i = 0; i < paramTokens.length; ++i) {
       var keyValueSplit = paramTokens[i].split('=');
       if (keyValueSplit.length != 2)
         continue;
       paramsDictionary[keyValueSplit[0]] = keyValueSplit[1];
     }
 
     // Order is important as later actions can override the effects
     // of previous actions.
     if ('page' in paramsDictionary) {
       // value is 1-based.
       this.viewport_.goToPage(paramsDictionary['page'] - 1);
     }
+    if ('zoom' in paramsDictionary)

[Lei Zhang, 2014/08/20 00:37:07]

I think order might also matter between page and zoom? Best to test with Acrobat
and see how it behaves.

One possible interpretation is:

(A) ?zoom=150,100,200&page=2 -> zoom to 150%, go to (100, 200), then go to page
2 -> ends up at top of page 2

vs

(B) ?page=2&zoom=150,100,200 -> go to page 2, zoom to 150%, go to (100, 200) ->
ends up in the middle of page 2

Other possible interpretations are we always do (A) or we always do (B).

[Nikhil, 2014/08/20 04:46:55]

As I understand, page should always be handled before zoom. Both
#zoom=150,100,200&page=2 and #page=2&zoom=150,100,200 should first go to page 2
and then zoom.

Please see "Specifying parameters in a URL" section of Adobe document.

+      this.handleZoomParam_(paramsDictionary['zoom']);
   },
 
   /**
    * @private
    * Update the loading progress of the document in response to a progress
    * message being received from the plugin.
    * @param {number} progress the progress as a percentage.
    */
   updateProgress_: function(progress) {
     this.progressBar_.progress = progress;
     if (progress == -1) {
       // Document load failed.
       this.errorScreen_.style.visibility = 'visible';
       this.sizer_.style.display = 'none';
       this.toolbar_.style.visibility = 'hidden';
       if (this.passwordScreen_.active) {
         this.passwordScreen_.deny();
         this.passwordScreen_.active = false;
       }
     } else if (progress == 100) {
       // Document load complete.
       this.handleOpenPDFParams_();
       this.loaded = true;
       var loadEvent = new Event('pdfload');
       window.dispatchEvent(loadEvent);
       this.sendScriptingMessage_({
         type: 'documentLoaded'
       });
       if (this.lastViewportPosition_)
         this.viewport_.position = this.lastViewportPosition_;

[raymes, 2014/08/20 00:14:21]

It shouldn't make a difference at present but I think this line should be moved
up above handleOpenPDFParams.

[Nikhil, 2014/08/21 11:36:50]

Done.

     }
   },
 
   /**
    * @private
    * An event handler for handling password-submitted events. These are fired
    * when an event is entered into the password screen.
    * @param {Object} event a password-submitted event.
    */
   onPasswordSubmitted_: function(event) {
@@ skipping 236 matching lines @@
 
   /**
    * @type {Viewport} the viewport of the PDF viewer.
    */
   get viewport() {
     return this.viewport_;
   }
 };
 
 var viewer = new PDFViewer();