From 8391aacb89f49b3ce96874d942dce61f9dbd4184 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Thu, 6 Jul 2017 13:13:22 +0200
Subject: [PATCH 1/2] Remove the scale-not-initialized hack from
 `webViewerResize` (in app.js)

Since we no longer, after PR 8555, allow changing the scale until the document is loaded, that hack is no longer necessary. Furthermore, no part of that event handling function needs to run unless a document is loaded.

The reason that this hack was initially added, is that previously the `ViewHistory` might be updated *before* `PDFViewerApplication.setInitialView` had run (in some cases leading to incorrect inital document scale). Since that is no longer possible, this is now dead code.
---
 web/app.js | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/web/app.js b/web/app.js
index ff7e5d912..784aa1537 100644
--- a/web/app.js
+++ b/web/app.js
@@ -1790,19 +1790,18 @@ function webViewerUpdateViewarea(evt) {
 }
 
 function webViewerResize() {
-  let currentScaleValue = PDFViewerApplication.pdfViewer.currentScaleValue;
+  let { pdfDocument, pdfViewer, } = PDFViewerApplication;
+  if (!pdfDocument) {
+    return;
+  }
+  let currentScaleValue = pdfViewer.currentScaleValue;
   if (currentScaleValue === 'auto' ||
       currentScaleValue === 'page-fit' ||
       currentScaleValue === 'page-width') {
     // Note: the scale is constant for 'page-actual'.
-    PDFViewerApplication.pdfViewer.currentScaleValue = currentScaleValue;
-  } else if (!currentScaleValue) {
-    // Normally this shouldn't happen, but if the scale wasn't initialized
-    // we set it to the default value in order to prevent any issues.
-    // (E.g. the document being rendered with the wrong scale on load.)
-    PDFViewerApplication.pdfViewer.currentScaleValue = DEFAULT_SCALE_VALUE;
+    pdfViewer.currentScaleValue = currentScaleValue;
   }
-  PDFViewerApplication.pdfViewer.update();
+  pdfViewer.update();
 }
 
 function webViewerHashchange(evt) {

From c253ee9ab8acb5729aefee3cd1638802ceea28c3 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Thu, 6 Jul 2017 13:44:01 +0200
Subject: [PATCH 2/2] Ensure that the document is rendered on load, no matter
 what happens, by always calling `PDFViewer.update` *after* the initial
 position has been set

---
 web/app.js | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/web/app.js b/web/app.js
index 784aa1537..8eacd7126 100644
--- a/web/app.js
+++ b/web/app.js
@@ -985,6 +985,12 @@ let PDFViewerApplication = {
 
         pdfViewer.currentScaleValue = pdfViewer.currentScaleValue;
         this.setInitialView(initialParams.hash);
+      }).then(function() {
+        // At this point, rendering of the initial page(s) should always have
+        // started (and may even have completed).
+        // To prevent any future issues, e.g. the document being completely
+        // blank on load, always trigger rendering here.
+        pdfViewer.update();
       });
     });