From 03f5dd2cf2f448ae372a8cc5a7fe3ca3d09d4034 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Mon, 17 Feb 2020 14:04:55 +0100
Subject: [PATCH] Add a `ignoreDestinationZoom` option/preference to allow
 users to preserve the current zoom level when navigating to internal
 destinations (issue 5064, 11606)

---
 extensions/chromium/preferences_schema.json |  6 ++++++
 web/app.js                                  |  1 +
 web/app_options.js                          |  5 +++++
 web/base_viewer.js                          | 13 +++++++++----
 web/pdf_link_service.js                     |  7 +++++++
 5 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/extensions/chromium/preferences_schema.json b/extensions/chromium/preferences_schema.json
index 1f2926a22..5b428bc6e 100644
--- a/extensions/chromium/preferences_schema.json
+++ b/extensions/chromium/preferences_schema.json
@@ -159,6 +159,12 @@
       "type": "boolean",
       "default": false
     },
+    "ignoreDestinationZoom": {
+      "title": "Ignore the zoom argument in destinations",
+      "description": "When enabled it will maintain the currently active zoom level, rather than letting the PDF document modify it, when navigating to internal destinations.",
+      "type": "boolean",
+      "default": false
+    },
     "enablePrintAutoRotate": {
       "title": "Automatically rotate printed pages",
       "description": "When enabled, pages whose orientation differ from the first page are rotated when printed.",
diff --git a/web/app.js b/web/app.js
index 1610f6249..ea8fa810c 100644
--- a/web/app.js
+++ b/web/app.js
@@ -354,6 +354,7 @@ const PDFViewerApplication = {
       eventBus,
       externalLinkTarget: AppOptions.get("externalLinkTarget"),
       externalLinkRel: AppOptions.get("externalLinkRel"),
+      ignoreDestinationZoom: AppOptions.get("ignoreDestinationZoom"),
     });
     this.pdfLinkService = pdfLinkService;
 
diff --git a/web/app_options.js b/web/app_options.js
index 0753178dc..3e4736299 100644
--- a/web/app_options.js
+++ b/web/app_options.js
@@ -86,6 +86,11 @@ const defaultOptions = {
     value: false,
     kind: OptionKind.VIEWER + OptionKind.PREFERENCE,
   },
+  ignoreDestinationZoom: {
+    /** @type {boolean} */
+    value: false,
+    kind: OptionKind.VIEWER + OptionKind.PREFERENCE,
+  },
   imageResourcesPath: {
     /** @type {string} */
     value: "./images/",
diff --git a/web/base_viewer.js b/web/base_viewer.js
index 78ab1fad9..5ee9d1d34 100644
--- a/web/base_viewer.js
+++ b/web/base_viewer.js
@@ -734,6 +734,8 @@ class BaseViewer {
    *   format: <page-ref> </XYZ|/FitXXX> <args..>
    * @property {boolean} [allowNegativeOffset] - Allow negative page offsets.
    *   The default value is `false`.
+   * @property {boolean} [ignoreDestinationZoom] - Ignore the zoom argument in
+   *   the destination array. The default value is `false`.
    */
 
   /**
@@ -744,6 +746,7 @@ class BaseViewer {
     pageNumber,
     destArray = null,
     allowNegativeOffset = false,
+    ignoreDestinationZoom = false,
   }) {
     if (!this.pdfDocument) {
       return;
@@ -834,10 +837,12 @@ class BaseViewer {
         return;
     }
 
-    if (scale && scale !== this._currentScale) {
-      this.currentScaleValue = scale;
-    } else if (this._currentScale === UNKNOWN_SCALE) {
-      this.currentScaleValue = DEFAULT_SCALE_VALUE;
+    if (!ignoreDestinationZoom) {
+      if (scale && scale !== this._currentScale) {
+        this.currentScaleValue = scale;
+      } else if (this._currentScale === UNKNOWN_SCALE) {
+        this.currentScaleValue = DEFAULT_SCALE_VALUE;
+      }
     }
 
     if (scale === "page-fit" && !destArray[4]) {
diff --git a/web/pdf_link_service.js b/web/pdf_link_service.js
index dac4f9618..dc8d95732 100644
--- a/web/pdf_link_service.js
+++ b/web/pdf_link_service.js
@@ -23,6 +23,9 @@ import { getGlobalEventBus, parseQueryString } from "./ui_utils.js";
  *   Defaults to using no target.
  * @property {string} [externalLinkRel] - Specifies the `rel` attribute for
  *   external links. Defaults to stripping the referrer.
+ * @property {boolean} [ignoreDestinationZoom] - Ignores the zoom argument,
+ *   thus preserving the current zoom level in the viewer, when navigating
+ *   to internal destinations. The default value is `false`.
  */
 
 /**
@@ -39,11 +42,13 @@ class PDFLinkService {
     externalLinkTarget = null,
     externalLinkRel = null,
     externalLinkEnabled = true,
+    ignoreDestinationZoom = false,
   } = {}) {
     this.eventBus = eventBus || getGlobalEventBus();
     this.externalLinkTarget = externalLinkTarget;
     this.externalLinkRel = externalLinkRel;
     this.externalLinkEnabled = externalLinkEnabled;
+    this._ignoreDestinationZoom = ignoreDestinationZoom;
 
     this.baseUrl = null;
     this.pdfDocument = null;
@@ -158,6 +163,7 @@ class PDFLinkService {
       this.pdfViewer.scrollPageIntoView({
         pageNumber,
         destArray: explicitDest,
+        ignoreDestinationZoom: this._ignoreDestinationZoom,
       });
     };
 
@@ -468,6 +474,7 @@ class SimpleLinkService {
     this.externalLinkTarget = null;
     this.externalLinkRel = null;
     this.externalLinkEnabled = true;
+    this._ignoreDestinationZoom = false;
   }
 
   /**