4 files changed, 18 insertions, 2 deletions
diff --git a/common/rfb/SDesktop.h b/common/rfb/SDesktop.h
index 560ee7ff..94e4b028 100644
--- a/common/rfb/SDesktop.h
+++ b/common/rfb/SDesktop.h
@@ -87,6 +87,10 @@ namespace rfb {
       return resultProhibited;
     }
 
+    // frameTick() is called whenever a frame update has been processed,
+    // signalling that a good time to render new data
+    virtual void frameTick(uint64_t msc) { (void)msc; }
+
     // InputHandler interface
     // pointerEvent(), keyEvent() and clientCutText() are called in response to
     // the relevant RFB protocol messages from clients.
diff --git a/common/rfb/VNCServer.h b/common/rfb/VNCServer.h
index 3f97634b..314367eb 100644
--- a/common/rfb/VNCServer.h
+++ b/common/rfb/VNCServer.h
@@ -42,6 +42,8 @@ namespace rfb {
     virtual void blockUpdates() = 0;
     virtual void unblockUpdates() = 0;
 
+    virtual uint64_t getMsc() = 0;
+
     // setPixelBuffer() tells the server to use the given pixel buffer (and
     // optionally a modified screen layout).  If this differs in size from
     // the previous pixel buffer, this may result in protocol messages being
diff --git a/common/rfb/VNCServerST.cxx b/common/rfb/VNCServerST.cxx
index 8d8dbfd7..bea32abe 100644
--- a/common/rfb/VNCServerST.cxx
+++ b/common/rfb/VNCServerST.cxx
@@ -1,5 +1,5 @@
 /* Copyright (C) 2002-2005 RealVNC Ltd.  All Rights Reserved.
- * Copyright 2009-2019 Pierre Ossman for Cendio AB
+ * Copyright 2009-2024 Pierre Ossman for Cendio AB
  * 
  * This is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -88,7 +88,7 @@ VNCServerST::VNCServerST(const char* name_, SDesktop* desktop_)
     renderedCursorInvalid(false),
     keyRemapper(&KeyRemapper::defInstance),
     idleTimer(this), disconnectTimer(this), connectTimer(this),
-    frameTimer(this)
+    msc(0), frameTimer(this)
 {
   slog.debug("creating single-threaded server %s", name.c_str());
 
@@ -257,6 +257,11 @@ void VNCServerST::unblockUpdates()
   }
 }
 
+uint64_t VNCServerST::getMsc()
+{
+  return msc;
+}
+
 void VNCServerST::setPixelBuffer(PixelBuffer* pb_, const ScreenSet& layout)
 {
   if (comparer)
@@ -634,6 +639,9 @@ void VNCServerST::handleTimeout(Timer* t)
 
     writeUpdate();
 
+    msc++;
+    desktop->frameTick(msc);
+
     // If this is the first iteration then we need to adjust the timeout
     frameTimer.repeat(1000/rfb::Server::frameRate);
   } else if (t == &idleTimer) {
diff --git a/common/rfb/VNCServerST.h b/common/rfb/VNCServerST.h
index 55d0c889..719b3f36 100644
--- a/common/rfb/VNCServerST.h
+++ b/common/rfb/VNCServerST.h
@@ -81,6 +81,7 @@ namespace rfb {
 
     virtual void blockUpdates();
     virtual void unblockUpdates();
+    virtual uint64_t getMsc();
     virtual void setPixelBuffer(PixelBuffer* pb, const ScreenSet& layout);
     virtual void setPixelBuffer(PixelBuffer* pb);
     virtual void setScreenLayout(const ScreenSet& layout);
@@ -206,6 +207,7 @@ namespace rfb {
     Timer disconnectTimer;
     Timer connectTimer;
 
+    uint64_t msc;
     Timer frameTimer;
   };