From 35775d50626c7d5d3f3c5db43179b690aa1b3738 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alberto=20Garci=CC=81a=20Hierro?= <alberto@garciahierro.com>
Date: Mon, 18 Jun 2018 18:03:49 +0100
Subject: [PATCH] Improve handling of OSD elements outside the viewport

- Don't crash when showing the preview for an item which is turned
on but non-visible due to its position.
- Move items outside of the viewport inside it when switching them
from hidden to visible.
---
 tabs/osd.js | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/tabs/osd.js b/tabs/osd.js
index e9603380..27d08c1e 100644
--- a/tabs/osd.js
+++ b/tabs/osd.js
@@ -1415,6 +1415,12 @@ OSD.GUI.updateFields = function() {
                         itemData.isVisible = !itemData.isVisible;
 
                         if (itemData.isVisible) {
+                            // Ensure the element is inside the viewport, at least partially.
+                            // In that case move it to the very first row/col, otherwise there's
+                            // no way to reposition items that are outside the viewport.
+                            if (itemData.position >= OSD.data.preview.length) {
+                                itemData.position = 0;
+                            }
                             $position.show();
                         } else {
                             $position.hide();
@@ -1515,12 +1521,18 @@ OSD.GUI.updatePreviews = function() {
                 y++;
                 continue;
             }
+            var previewPos = j + x + (y * OSD.data.display_size.x);
+            if (previewPos >= OSD.data.preview.length) {
+                // Character is outside the viewport
+                x++;
+                continue;
+            }
             // test if this position already has a character placed
-            if (OSD.data.preview[j+x+(y*OSD.data.display_size.x)][0] !== null) {
+            if (OSD.data.preview[previewPos][0] !== null) {
                 // if so set background color to red to show user double usage of position
-                OSD.data.preview[j+x+(y*OSD.data.display_size.x)] = [item, charCode, 'red'];
+                OSD.data.preview[previewPos] = [item, charCode, 'red'];
             } else {
-                OSD.data.preview[j+x+(y*OSD.data.display_size.x)] = [item, charCode];
+                OSD.data.preview[previewPos] = [item, charCode];
             }
             // draw the preview
             var img = new Image();