From 5c94900026437ed108f29eb54cfe31f2ce0deba6 Mon Sep 17 00:00:00 2001
From: Klaus Schmidinger <vdr@tvdr.de>
Date: Tue, 7 Nov 2017 15:42:47 +0100
Subject: OSD menus now try to keep the offset of the list cursor at a constant
 position on the screen, even if the list is modified while being displayed

---
 HISTORY   | 4 +++-
 osdbase.c | 9 +++++++--
 osdbase.h | 3 ++-
 3 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/HISTORY b/HISTORY
index 0f62427d..ed782f3a 100644
--- a/HISTORY
+++ b/HISTORY
@@ -9162,7 +9162,7 @@ Video Disk Recorder Revision History
   a subdirectory.
 - SVDRP peering can now be limited to the default SVDRP host (see MANUAL for details).
 
-2017-11-02: Version 2.3.9
+2017-11-07: Version 2.3.9
 
 - Updated the Italian OSD texts (thanks to Diego Pierotto).
 - Updated the Finnish OSD texts (thanks to Rolf Ahrenberg).
@@ -9188,3 +9188,5 @@ Video Disk Recorder Revision History
   instead.
 - The timeout for the channel display is now reset whenever the channel or EPG data
   changes.
+- OSD menus now try to keep the offset of the list cursor at a constant position on
+  the screen, even if the list is modified while being displayed.
diff --git a/osdbase.c b/osdbase.c
index ac8026ff..dea1d995 100644
--- a/osdbase.c
+++ b/osdbase.c
@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: osdbase.c 4.2 2017/04/03 12:30:52 kls Exp $
+ * $Id: osdbase.c 4.3 2017/11/07 15:42:47 kls Exp $
  */
 
 #include "osdbase.h"
@@ -92,6 +92,7 @@ cOsdMenu::cOsdMenu(const char *Title, int c0, int c1, int c2, int c3, int c4)
   SetTitle(Title);
   SetCols(c0, c1, c2, c3, c4);
   first = 0;
+  lastOffset = 0;
   current = marked = -1;
   subMenu = NULL;
   helpRed = helpGreen = helpYellow = helpBlue = NULL;
@@ -253,7 +254,7 @@ void cOsdMenu::Display(void)
          }
      if (current < 0)
         current = 0; // just for safety - there HAS to be a current item!
-     first = min(first, max(0, count - displayMenuItems)); // in case the menu size has changed
+     first = max(0, min(first, max(0, count - displayMenuItems))); // in case the menu size has changed
      if (current - first >= displayMenuItems || current < first) {
         first = current - displayMenuItems / 2;
         if (first + displayMenuItems > count)
@@ -281,6 +282,9 @@ void cOsdMenu::Display(void)
 void cOsdMenu::SetCurrent(cOsdItem *Item)
 {
   current = Item ? Item->Index() : -1;
+  if (current >= 0 && lastOffset > 0)
+     first = max(0, current - lastOffset);
+  lastOffset = 0;
 }
 
 void cOsdMenu::RefreshCurrent(void)
@@ -326,6 +330,7 @@ void cOsdMenu::Clear(void)
 {
   if (marked >= 0)
      SetStatus(NULL);
+  lastOffset = (current > first) ? current - first : 0;
   first = 0;
   current = marked = -1;
   cList<cOsdItem>::Clear();
diff --git a/osdbase.h b/osdbase.h
index 91b795d5..8e2a77ad 100644
--- a/osdbase.h
+++ b/osdbase.h
@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: osdbase.h 4.2 2017/04/03 12:02:16 kls Exp $
+ * $Id: osdbase.h 4.3 2017/11/07 15:31:24 kls Exp $
  */
 
 #ifndef __OSDBASE_H
@@ -92,6 +92,7 @@ private:
   char *title;
   int cols[cSkinDisplayMenu::MaxTabs];
   int first, current, marked;
+  int lastOffset;;
   eMenuCategory menuCategory;
   eMenuSortMode menuSortMode;
   eMenuOrientation menuOrientation;
-- 
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