From f78b348cff5108229a544d686f5dbc0c149f9e09 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Mon, 7 Sep 2020 10:27:32 +0200
Subject: [PATCH] Support broken /FitH destinations that are missing the "top"
 value (bug 1663390)

See https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/PDF32000_2008.pdf#G11.2095870
---
 web/base_viewer.js | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/web/base_viewer.js b/web/base_viewer.js
index 4ed2ba4b0..9d7ac1d71 100644
--- a/web/base_viewer.js
+++ b/web/base_viewer.js
@@ -852,6 +852,10 @@ class BaseViewer {
         if (y === null && this._location) {
           x = this._location.left;
           y = this._location.top;
+        } else if (typeof y !== "number") {
+          // The "top" value isn't optional, according to the spec, however some
+          // bad PDF generators will pretend that it is (fixes bug 1663390).
+          y = pageHeight;
         }
         break;
       case "FitV":