Make the comparing update tracker a bit more flexible. It can now be in an

"auto" state where it will be enabled until we deem that the client is better
of without it (currently triggered by explicitly stating a low compression
level).


git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@4809 3789f03b-4d11-0410-bbf8-ca57d06f2519

1 files changed, 37 insertions, 12 deletions

diff --git a/common/rfb/ComparingUpdateTracker.cxx b/common/rfb/ComparingUpdateTracker.cxx
index 42a9e192..43287e07 100644
--- a/common/rfb/ComparingUpdateTracker.cxx
+++ b/common/rfb/ComparingUpdateTracker.cxx
@@ -25,7 +25,7 @@
 using namespace rfb;
 
 ComparingUpdateTracker::ComparingUpdateTracker(PixelBuffer* buffer)
-  : fb(buffer), oldFb(fb->getPF(), 0, 0), firstCompare(true)
+  : fb(buffer), oldFb(fb->getPF(), 0, 0), firstCompare(true), enabled(true)
 {
     changed.assign_union(fb->getRect());
 }
@@ -37,35 +37,60 @@ ComparingUpdateTracker::~ComparingUpdateTracker()
 
 #define BLOCK_SIZE 16
 
-void ComparingUpdateTracker::compare()
+bool ComparingUpdateTracker::compare()
 {
   std::vector<Rect> rects;
   std::vector<Rect>::iterator i;
 
+  if (!enabled)
+    return false;
+
   if (firstCompare) {
     // NB: We leave the change region untouched on this iteration,
     // since in effect the entire framebuffer has changed.
     oldFb.setSize(fb->width(), fb->height());
+
     for (int y=0; y<fb->height(); y+=BLOCK_SIZE) {
       Rect pos(0, y, fb->width(), __rfbmin(fb->height(), y+BLOCK_SIZE));
       int srcStride;
       const rdr::U8* srcData = fb->getPixelsR(pos, &srcStride);
       oldFb.imageRect(pos, srcData, srcStride);
     }
+
     firstCompare = false;
-  } else {
-    copied.get_rects(&rects, copy_delta.x<=0, copy_delta.y<=0);
-    for (i = rects.begin(); i != rects.end(); i++)
-      oldFb.copyRect(*i, copy_delta);
 
-    changed.get_rects(&rects);
+    return false;
+  }
+
+  copied.get_rects(&rects, copy_delta.x<=0, copy_delta.y<=0);
+  for (i = rects.begin(); i != rects.end(); i++)
+    oldFb.copyRect(*i, copy_delta);
 
-    Region newChanged;
-    for (i = rects.begin(); i != rects.end(); i++)
-      compareRect(*i, &newChanged);
+  changed.get_rects(&rects);
 
-    changed = newChanged;
-  }
+  Region newChanged;
+  for (i = rects.begin(); i != rects.end(); i++)
+    compareRect(*i, &newChanged);
+
+  if (changed.equals(newChanged))
+    return false;
+
+  changed = newChanged;
+
+  return true;
+}
+
+void ComparingUpdateTracker::enable()
+{
+  enabled = true;
+}
+
+void ComparingUpdateTracker::disable()
+{
+  enabled = false;
+
+  // Make sure we update the framebuffer next time we get enabled
+  firstCompare = true;
 }
 
 void ComparingUpdateTracker::compareRect(const Rect& r, Region* newChanged)